SAT Biology Vocabulary Flashcards
(850 cards)
1
Q
Structures in grasshoppers for removal of the nitrogenous waste uric acid.
A
malpighian tubule
2
Q
mitosis
A
Type of cell division for growth and repair that produces two genetically identical daughter cells with the same chromosome number as the parent cell. Consists of four phases: prophase, metaphase, anaphase, and telophase.
3
Q
dehydration synthesis
A
Also known as synthesis. Process by which molecules are bonded together to form a larger molecule with the removal of water.
4
Q
Specialized region in the root of a plant for storage.
A
pith
5
Q
glyceraldehyde-3-phosphate
A
(Also G3P or PGAL.) First sugar produced by photosynthesis.
6
Q
introns
A
Intervening, noncoding sequences of DNA located between genes.
7
Q
parallel evolution
A
Two related species that have made similar evolutionary adaptations after their divergence form a common ancestor.
8
Q
Process by which ATP is produced as a special enzyme moves a phosphate from one molecule to ADP. How energy is produced during glycolysis and the Krebs cycle.
A
substrate level phosphorylation
9
Q
Myofilaments that make up the thick filaments in skeletal muscle.
A
myosin
10
Q
The outermost layer of an embryo, which develops into skin and nervous system.
A
ectoderm
11
Q
acoelomate
A
An animal that has no true coelom. Flatworms are an example.
12
Q
anther
A
Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament.
13
Q
Part of the testes where sperm become mobile.
A
epididymis
14
Q
electron transport chain
A
(Also ETC.) Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation.
15
Q
phenotype
A
The traits an organism expresses.
16
Q
glycerol
A
Combines with fatty acids to make lipids.
17
Q
Plant whose seed does not break into two parts. An example is corn.
A
monocotyledon
18
Q
spermatogenesis
A
Formation of sperm by meiotic cell division.
19
Q
Process by which cells continue to differentiate, producing organs from the three embryonic germ layers.
A
organogenesis
20
Q
Pressure exerted when a plant cell sweats.
A
turgor pressure
21
Q
An inherited disease characterized by the inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet, otherwise serious mental retardation will result.
A
Phenylketonuria
22
Q
Type of cell division in sexually reproducing organisms that produces haploid (n) gametes.
A
meiosis
23
Q
pathogen
A
Organism that causes disease.
24
Q
Characteristic of proteins; a change in shape that stops the protein from functioning.
A
denature
25
vegetative propagation
Asexual reproduction in a plant where a piece of the root, stem, or leaf produces an entirely new plant genetically identical to the parent plant. Examples are grafting, cuttings, bulbs, and runners.
26
active transport
Movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy.
27
Expressed sequences of DNA. DNA that codes for particular polypeptides.
exons
28
meristem tissue
Plant tissue that is always dividing. An example is cambium tissue.
29
Noncoding regions of DNA. Most of the human genome consists of noncoding regions.
junk
30
Incorporation of carbon dioxide into a sugar. It occurs during the cyclical process called the Calvin cycle.
carbon fixation
31
multiple alleles
When there are more than two allelic forms of a gene. For example in humans, there are more than 2 alleles for blood type. There are A, B, and O.
32
A degenerative inherited disease of the nervous system resulting in certain and early death. The gene that causes it is dominant.
Huntington's disease
33
Cellular process of engulfing food and encapsulating it in a vacuole.
phagocytosis
34
An error that sometimes happens during meiosis in which homologous chromosomes fail to separate as they should.
nondisjunction
35
An organism's genetic material.
genome
36
parasitism
Symbiotic relationship (+/-) where one organism, the parasite, benefits while the host is harmed.
37
A fragment of a chromosome becomes attached to a non homologous chromosome.
translocation
38
spliceosomes
Special molecules that assist in the editing of mRNA during RNA processing.
39
Extra embryonic membrane in bird's egg. It exchanges respiratory gases to and from the embryo.
allantois
40
Symbiotic bacterium that lives in the nodules on roots of specific legumes and that fixes nitrogen gas from the air into a form of nitrogen the plant requires.
rhizobium
41
Sinuses. Cavities in the body of insects, like grasshoppers, for exchange of nutrients and wastes.
hemocoels
42
This type of natural selection eliminates the extremes and favors the more common intermediate forms.
stabilizing selection
43
adenosine triphosphate
(Also called ATP.) Special high-energy molecule that stores energy for immediate use in the cell.
44
Levels of organization in our system of classification: domain, kingdom, phylum, class, order, family, genus, and species. Domain or kingdom includes the most different organism, while species includes the most similar organisms.
Taxon (Taxa, plural)
45
A small population, which is not representative of the larger population, breaks away from the larger one to colonize a new area. Rare alleles may be under- or overrepresented.
founder effect
46
Combines with fatty acids to make lipids.
glycerol
47
Anything that triggers an antibody response.
antigens
48
A normal process in which homologous chromatids exchange genetic material.
crossing-over
49
Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
messenger RNA or mRNA
50
Symbiotic structures consisting of the plant's roots intermingled with the hyphae (filaments) of a fungus, which greatly increase the quantity of nutrients that a plant can absorb.
mycorrhizae
51
Solutions containing equal concentrations of solute.
isotonic
52
ovule
The structure within the ovary of a flower where the ova (female gametophyte) are produced.
53
excited state
When an atom absorbs energy, its electrons move to a higher energy level.
54
Structure in birds, insects, and earthworms where mechanical digestion of food occurs.
gizzard
55
Cessation of the menstrual cycle.
menopause
56
The way in which DNA replicates itself.
semiconservative replication (The new DNA molecule consists of one old strand and one new strand.)
57
hydrophilic
Soluble in water. Hydrophilic substances are either polar or ionic.
58
Modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.
C-4 photosynthesis
59
population
Group of individuals of one species living in one area that have the ability of interbreeding and interacting with each other.
60
homeotherm
Endotherm. Animals that maintain a consistent body temperature. Examples are birds, mammals, and some reptiles.
61
synapsis
The process in which homologous chromosomes pair up. This occurs during prophase I.
62
agonistic behavior
Aggressive behavior.
63
hermaphrodites
Organisms that contain both female and male sex organs.
64
anion
A Negative ION.
65
erythrocytes
Red blood cells.
66
translation
The process in which the DNA code is translated into an amino acid sequence and a polypeptide is formed. Occurs at the ribosome.
67
golgi apparatus
Cell organelle that packages and secretes substances for the cell.
68
polymerase chain reaction
A cell-free, automated technique by which a piece of DNA can be rapidly copied or amplified. Useful in genetic engineering.
69
bacterial transformation
The ability of bacteria alter their genetic makeup by up taking foreign DNA from another bacterial cell and incorporating it into their own. Discovered by the scientist named Griffith.
70
NAD
(Also nicotinamide adenine dinucleotide.) Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
71
Animals that normally eat both meat and vegetables in their diet.
omnivores
72
secretin
Digestive hormone that stimulates the pancreas to release bicarbonate to neutralize acid in the duodenum.
73
A property of plant cells, swollen.
turgid
74
Intake and distribution of substances in cells or tissue.
transport
75
gel electrophoresis
Process that separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field.
76
Anthophyta or flowering plants.
angiosperms
77
sclerenchyma cells
Plant cells that have very thick primary and secondary cell walls fortified with lignin. Their function is purely support.
78
Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
flavin adenine dinucleotide or FAD
79
An error in the DNA in which the entire reading frame is altered. This can be caused by an insertion or deletion.
frameshift
80
Diffusion of water across a membrane.
osmosis
81
The sum total of all the life functions.
metabolism
82
grana
Membranes within chloroplasts that consist of thylakoid membranes and are the sites of the light-dependent reactions of photosynthesis.
83
Swollen part of pistil of a flower that contains the ovule, where one or more ova are produced.
ovary
84
microtubules
Thick hollow tubes that make up the cilia, flagella, and spindle fibers.
85
cystic fibrosis
The most common lethal genetic disease in the United States, 1 out of 25 Caucasians is a carrier. Characterized by build-up of extracellular fluid in the lungs and digestive tract.
86
chemiosmosis
This is how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthetase channels and transfer energy to molecules of ATP.
87
messenger RNA
(Also mRNA.) Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
88
triploblastic
An animal consisting of three cell layers. This includes every animal more sophisticated than flatworms.
89
Extracted from bacteria; they cut DNA at specific recognition sequences or sites, such as GAATTC.
restriction enzymes
90
Lateral growth of a plant.
secondary growth
91
Chemicals that resist a change in pH.
buffers
92
hemocoels
Sinuses. Cavities in the body of insects, like grasshoppers, for exchange of nutrients and wastes.
93
convergent evolution
Type of evolution where unrelated species occupying the same environment and subjected to similar selective pressures show similar adaptations. The classic example is the whale (a mammal) and the fish.
94
peptidases
Enzymes that break down proteins into amino acids.
95
Family tree that indicates the phenotype of one trait being studied for every member of a family.
pedigree
96
mitochondrion
Cell organelle that produces ATP. Present in both plants and animals.
97
Special sites where replication begins in eukaryotic cells.
origins of replication
98
Millions of fingerlike projections that line the small intestine and absorb all nutrients that were previously released from digested food.
villus (villi, plural)
99
dipeptide
A molecule consisting of two amino acids.
100
The specific sites on DNA that restriction enzymes cut.
recognition sequences or recognition sites
101
Special high-energy molecule that stores energy for immediate use in the cell.
adenosine triphosphate or ATP
102
commensalism
Symbiotic relationship in which one organism benefits and one is not affected by the other organism (+/o).
103
Outermost circle of leaves around a flower that are green and closely resemble ordinary leaves.
sepals
104
Consists of all the organisms living in one area.
community
105
net primary productivity
Gross primary productivity minus the energy used by the primary producers for respiration.
106
Chemical produced in the liver and released from the gallbladder that emulsifies fats. It is NOT an enzyme.
bile
107
reproduction
Ability to generate offspring.
108
Relaxation of the ventricles of the heart. Normal diastolic pressure is 120 mm Hg.
diastole
109
biological magnification
Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies that those at lower trophic levels.
110
denature
Characteristic of proteins; a change in shape that stops the protein from functioning.
111
Organisms that obtain food from decaying organic matter.
saprobes
112
The branch of science that uses recombinant DNA techniques for practical purposes.
biotechnology or genetic engineering
113
CAM
(Also crassulacean acid metabolism.) A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
114
Where components of ribosomes are synthesized. This is a prominent region within the nucleus of a cell that is not dividing.
nucleolus
115
Openings in leaves to exchange photosynthetic gases; water vapor, carbon dioxide, and oxygen.
stomates
116
auxins
Growth hormones in plants that are responsible for phototropism and apical dominance, the preferential growth of a plant upward (toward the sun) rather than laterally.
117
System of taxonomy that we use today, developed by Carl von Linne. In this system, every organism has a two-part name, like Homo sapiens.
binomial nomenclature
118
In primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.
gametangia
119
turgor pressure
Pressure exerted when a plant cell sweats.
120
Organisms that thrive in environments with high salt concentrations like Utah's Great Salt Lake.
halophiles
121
ovary
Swollen part of pistil of a flower that contains the ovule, where one or more ova are produced.
122
digestion
Enzymatic breakdown, hydrolysis, of food so it is small enough to be assimilated into the body.
123
adventitious roots
Roots that arise above ground; examples are aerial roots and prop roots.
124
angiosperms
Anthophyta or flowering plants.
125
One type of organic molecule. It consists of one glycerol plus three fatty acids.
lipid
126
leucoplast
Type of plastid that stores starch.
127
Modified epithelium containing chloroplasts that control the opening and closing of the stomates by a change in shape.
guard cells
128
carrying capacity (K)
A limit to the number of individuals that can occupy one area at a particular time.
129
testes (testis, singular)
Male gonads; the site of sperm formation.
130
oogenesis
Formation of ova by meiotic cell division.
131
organogenesis
Process by which cells continue to differentiate, producing organs from the three embryonic germ layers.
132
sister chromatids
A replicated chromosome consists of two fo these, where one is an exact copy of the other.
133
crassulacean acid metabolism
(Also CAM.) A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
134
visible spectrum
Wavelengths of light that humans can see: 380 nm to 750 nm.
135
uterus
Where the blastula stage of the embryo implants and develops during the nine-month gestation if fertilization occurs.
136
Enzymes that break down proteins into amino acids.
peptidases
137
Amount of energy converted to chemical energy by photosynthesis per unit in an ecosystem.
gross primary productivity
138
Where the blastula stage of the embryo implants and develops during the nine-month gestation if fertilization occurs.
uterus
139
hemophilia
An inherited disease caused by the absence of one or more proteins necessary for normal blood clotting.
140
autonomic nervous system
Part of the nervous system that controls automatic functions, such as heart and breathing rate.
141
regulation
Ability to maintain internal stability, homeostasis.
142
symplast
System of transport within a plant consisting of openings in cell walls called plasmodesmata.
143
A phenomenon in bacteria. They have the ability to transform themselves by transferring genetic factors from one bacteria cell to another.
transformation
144
Sign stimuli exchanged between members of the same species.
releaser
145
Made of microtubules, these assist in cell division.
spindle fibers
146
Vertical growth of a plant.
primary growth
147
Structures located on the tips of a gametophyte plant that produces eggs.
archegonia
148
final transcript
The strand of mRNA that is sent to the ribosome after processing. The final transcript is much shorter than the initial transcript.
149
initial transcript
Strand of mRNA before it is processed. The initial transcript is much longer than the final transcript.
150
Procedure that analyzes the size, shape, and number of chromosomes.
karyotype
151
Rapid mitotic cell division of the zygote that begins immediately after fertilization.
cleavage
152
Published a treatise on population growth, disease, and famine in 1798 that influenced Darwin in the development on his theory of natural selection. Malthus stated that populations tend to grow exponentially, to overpopulate, and to exceed their resources.
Malthus
153
reabsorption
In the nephron of the kidneys, a process by which most of the water and solutes (glucose, amino acids, and vitamins) that initially entered the tubule during filtration are transported back into the capillaries and, thus, back to the body.
154
Condition of an electron when it is not excited. It is in its lowest energy level.
ground state
155
Specialized membranes that make up the grana in chloroplasts, the site of the light-dependent reactions.
thylakoids
156
Microscopic air sacs in the lung where diffusion of the respiratory gases, oxygen and carbon dioxide, occurs.
alveolus (alveoli, plural)
157
trichomes
Tiny, spikelike projections on some leaves for protection.
158
Cavities in the body for exchange of fluid. Called hemocoel in grasshoppers.
sinuses
159
thylakoids
Specialized membranes that make up the grana in chloroplasts, the site of the light-dependent reactions.
160
The structure within the ovary of a flower where the ova (female gametophyte) are produced.
ovule
161
cotyledon
Food for the growing embryo in a dicot seed. The cells that make up the cotyledon are triploid (3n).
162
Intervening, noncoding sequences of DNA located between genes.
introns
163
The heritable material, passed from parent to offspring.
deoxyribonucleic acid or DNA
164
A negative ion.
anion
165
Vascular cylinder in a plant root.
stele
166
photosynthetic pigments
Chemicals that absorb light energy and use it to carry out photosynthesis. Examples are chlorophyll a, chlorophyll b, carotenoids, and phycobilins.
167
DNA in the nucleus that is wrapped with special proteins called histones into a visible network.
chromatin network
168
leukocyte
White blood cells.
169
accurate
Correct; not in error
170
Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.
cytochromes
171
Membrane that encloses the yolk of an egg; food for the growing embryo.
yolk sac
172
photolysis
The process that occurs during the light-dependent reactions in which water is ripped apart to provide electrons to replace those lost by chlorophyll a. Oxygen is released.
173
prions
Misfolded proteins that cause mad cow disease.
174
gastrin
Digestive hormone that stimulates sustained secretion of gastric juice from the stomach.
175
Taxon (Taxa, plural)
Levels of organization in our system of classification: domain, kingdom, phylum, class, order, family, genus, and species. Domain or kingdom includes the most different organism, while species includes the most similar organisms.
176
Ability to generate offspring.
reproduction
177
villus (villi, plural)
Millions of fingerlike projections that line the small intestine and absorb all nutrients that were previously released from digested food.
178
molecule
The name given to two or more atoms joined by a covalent bond.
179
Male part of flower where sperm (pollen) is produced by meiosis. Sits atop the filament.
anther
180
Any change in a gene or chromosome.
mutation
181
Semiliquid portion of the cytoplasm.
cytosol
182
macroevolution
Refers to speciation, the formation of an entirely new species.
183
Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
NAD or nicotinamide adenine dinucleotide
184
diffusion
The flow of molecules from a higher concentration to a lower concentration. There are two types: simple and facilitated.
185
An animal with a false coelom.
pseudocoelomate (An example is a roundworm.)
186
Also known as the citric acid cycle; the first stage of the aerobic phase of cellular respiration. It occurs in the inner matrix of mitochondria.
Krebs cycle
187
Structure in birds, insects, and earthworms, among others, for temporary storage of food.
crop
188
Cell organelle that packages and secretes substances for the cell.
golgi apparatus
189
Food for the growing embryo in a dicot seed. The cells that make up the cotyledon are triploid (3n).
cotyledon
190
chitin
A polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.
191
The middle layer of an embryo that develops into blood, bones, and muscle.
mesoderm
192
Duct that carries sperm during ejaculation from the testes to the penis.
vas deferens
193
A Y-shaped region where the new strands of DNA are elongating during DNA replication.
replication fork
194
gametangia
In primitive plants, a protective jacket of cells in which gametes and zygotes develop and which prevents drying out.
195
Hormone released by the pancreas that lowers blood sugar.
insulin
196
polarized
The condition of an axon of a nerve when it is at rest, also known as resting potential. Sodium and potassium are pumped to opposite sides of the membrane.
197
epididymis
Part of the testes where sperm become mobile.
198
saprobes
Organisms that obtain food from decaying organic matter.
199
An intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.
hydrogen bonding
200
reduction
Gain of electrons.
201
lysosome
Cell organelle that consists of digestive (hydrolytic) enzymes and is the principal site of intracellular digestion in the cell.
202
Any abnormal condition of the chromosomes.
aneuploidy
203
Organisms that play a vital role in the ecosystem and that recycle dead organic mater. Examples are bacteria and fungi.
decomposer
204
Movement of cytoplasm around the cell.
cyclosis
205
territory
Area an organism defends and from which other members of the community are excluded.
206
polymers
Molecules that are chains of repeating units; proteins and DNA are examples.
207
genetic drift
Change in the gene pool due chance. Two examples are the bottleneck effect and the founder effect.
208
When an atom absorbs energy, its electrons move to a higher energy level.
excited state
209
sex-influenced trait
Inheritance is influenced by the sex of the individual carrying the trait.
210
Moving from place to place.
locomotion
211
The ability of bacteria alter their genetic makeup by up taking foreign DNA from another bacterial cell and incorporating it into their own. Discovered by the scientist named Griffith.
bacterial transformation
212
An animal that has a true coelom, or body cavity. All chordates are coelomates.
coelomate
213
redox
A combination of reduction and oxidation reactions.
214
endoplasmic reticulum
System of transport channels within the cytoplasm of a eukaryotic cell.
215
polyploid
An organism with extra sets of chromosomes (3n, 4n, etc.) Commonly occurs in plants.
216
tRNA
(Also transfer RNA.) Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
217
fragmentation
A single parent organism breaks into parts that regenerate into new individuals. Reproduction in sponges, planaria, and sea stars.
218
endoderm
The innermost layer of an embryo, which develops into the viscera or the digestive system.
219
A single parent organism breaks into parts that regenerate into new individuals. Reproduction in sponges, planaria, and sea stars.
fragmentation
220
phagocytosis
Cellular process of engulfing food and encapsulating it in a vacuole.
221
cleavage
Rapid mitotic cell division of the zygote that begins immediately after fertilization.
222
ionic bonds
Bonds between atoms that form by transferring electrons.
223
tracheids
Cells that, along with vessel elements, make up xylem.
224
The release of substances from a cell.
exocytosis
225
Correct; not in error
accurate
226
directional selection
Changing environmental conditions give rise to the type of natural selection. One phenotype replaces another in the gene pool.
227
The anaerobic phase of aerobic respiration. One molecule of glucose breaks apart into two molecules of pyruvate.
glycolysis
228
Radioactive substance that can be used to track a substance as it moves through an organism or through a metabolic pathway. They can be used research or as a diagnostic tool in medicine.
tracer
229
exocytosis
The release of substances from a cell.
230
nematocysts
Stingers found in cnidocytes of cnidarians.
231
Band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.
cardiac sphincter
232
geographic isolation
Separation by mountain ranges, canyons, rivers, lakes, or glaciers, may cause significant isolation.
233
cytokinesis
Division of the cytoplasm. In animal cells, a cleavage furrow forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each other. In plant cells, a cell plate from down the middle of the cell.
234
Specialized region in a plant root or stem for storage and support.
cortex
235
Structures within the villi that line the small intestine and that absorb fatty acids and glycerol into the lymphatic system.
lacteal
236
sieve tube elements
Make up phloem, along with companion cells.
237
Combining of small molecules or substances into larger, more complex ones.
synthesis
238
Refers to speciation, the formation of an entirely new species.
macroevolution
239
Includes all the organisms with which an organism might react in an ecosystem.
biotic factor
240
In the newest system of classification, all organisms are classified in one of three domains, which are further divided into kingdom, phylum, class, order, family, genus, and species.
domain
241
centrioles
Responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle.
242
Plant whose seed easily breaks in two.
dicotyledon
243
Having two different alleles. Example: B/b.
heterozygous hybrid
244
gymnosperms
Confers or cone-bearing trees.
245
A molecule consisting of two amino acids.
dipeptide
246
lacteal
Structures within the villi that line the small intestine and that absorb fatty acids and glycerol into the lymphatic system.
247
One of the simplest forms of learning in which an animal comes to ignore a persistent stimulus so it can go about its business.
habituation
248
FAD
(Also flavin adenine dinucleotide.) Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
249
serum
Plasma without the clotting factors.
250
Organelles found only in plant cells; chloroplast is one example.
plastids
251
Throat.
pharynx
252
Traits carried on the X chromosome.
sex-linked
253
Amount of heat that must be absorbed in order for 1 gram of a substance to change its temperature by 1 degree Celsius.
specific heat
254
somatic cells
Body cells.
255
puberty
Onset of the menstrual cycle in girls and sperm production in boys.
256
Internal stability.
homeostasis
257
Also known as synthesis. Process by which molecules are bonded together to form a larger molecule with the removal of water.
dehydration synthesis
258
sign stimuli
Initiate a fixed action pattern.
259
heterozygous hybrid
Having two different alleles. Example: B/b.
260
Krebs cycle
Also known as the citric acid cycle; the first stage of the aerobic phase of cellular respiration. It occurs in the inner matrix of mitochondria.
261
Flap of cartilage in the back of the throat that directs food to the esophagus.
epiglottis
262
cyclosis
Movement of cytoplasm around the cell.
263
Loss of electrons.
oxidation
264
Make up phloem, along with companion cells.
sieve tube elements
265
Body cells.
somatic cells
266
hypothalamus
Major gland in the brain that is the bridge between the endocrine and nervous system.
267
Huntington's disease
A degenerative inherited disease of the nervous system resulting in certain and early death. The gene that causes it is dominant.
268
Traditional-looking plant cell. Have a primary cell wall that is thin and flexible but lack a secondary cell wall.
parenchyma cells
269
semiconservative replication
The way in which DNA replicates itself. The new DNA molecule consists of one old strand and one new strand.
270
genome
An organism's genetic material. The human genome consists of 3 billion base pairs of DNA and about 30,000 genes.
271
taxonomy
System by which we name and classify all organisms, living and extinct.
272
stabilizing selection
This type of natural selection eliminates the extremes and favors the more common intermediate forms.
273
incomplete dominance
An inheritance pattern characterized by blending of traits. An example is crossing an animal with black fur with one with white fur, producing offspring with gray fur.
274
Major gland in the brain that is the bridge between the endocrine and nervous system.
hypothalamus
275
Organisms that must take in all their nutrients.
heterotrophs
276
Initiate a fixed action pattern.
sign stimuli
277
flavin adenine dinucleotide
(Also FAD.) Coenzyme that shuttles protons and electrons from glycolysis and the Krebs cycle to the electron transport chain.
278
insertion
A mutation where one nucleotide inserts itself into an existing strand. This mutation can cause a frameshift.
279
A polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi.
chitin
280
Long, usually thin stalk of the pistil of a flower.
style
281
medusa
Upside-down bowl-shaped body type.
282
Area an organism defends and from which other members of the community are excluded.
territory
283
Class of nucleotides, includes thymine and cytosine.
pyrimidines
284
Special molecules that assist in the editing of mRNA during RNA processing.
spliceosomes
285
xylem
Vessels in plants that carry water and nutrients from the soil to the rest of the plant.
286
polysaccharides
Molecules that consist of many monosaccharides joined together. Starch and chitin are examples.
287
A measure of clarity of an image seen under a microscope.
resolution
288
budding
Splitting off of new individuals from existing ones. How reproduction occurs in hydra.
289
Ability to maintain internal stability, homeostasis.
regulation
290
chromatin network
DNA in the nucleus that is wrapped with special proteins called histones into a visible network.
291
founder effect
A small population, which is not representative of the larger population, breaks away from the larger one to colonize a new area. Rare alleles may be under- or overrepresented.
292
Part of the chloroplasts that holds the grana.
stroma
293
imprinting
Learning that occurs during a sensitive or critical period in the early life of an individual and is irreversible for the length of that period.
294
Increase in average temperature of Earth. It is due to the greenhouse effect.
global warming
295
genotype
The kind of genes an organism has.
296
cortex
Specialized region in a plant root or stem for storage and support.
297
The strand of mRNA that is sent to the ribosome after processing.
final transcript
298
ATP
(Also called adenosine triphosphate.) Special high-energy molecule that stores energy for immediate use in the cell.
299
Cell shrinking, occurs when a cell is in a hypertonic environment.
plasmolysis
300
sinoatrial (SA) node
Pacemaker of the heart.
301
Type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers.
chromoplasts
302
The process in which the DNA code is translated into an amino acid sequence and a polypeptide is formed. Occurs at the ribosome.
translation
303
alcohol fermentation
The process by which certain cells convert pyretic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen.
304
The theory that organisms descended from a common ancestor gradually, over a long period of time, in a linear of branching fashion.
gradualism
305
stamen
Male part of the flower, consists of anther and filament.
306
antheridia
Structures located on the tips of a gametophyte plant and that produce sperm.
307
Elaborate molecule that sits within neuron membranes and pumps sodium and potassium ions across the membrane.
sodium-potassium pump
308
Amount of time it takes for a radioactive isotope to decay to half its mass.
half-life
309
classical conditioning
Type of associative learning. Pavlov trained dogs to associate the sound of a bell with food. The result of this conditioning was that dogs would salivate upon merely hearing the sound of the bell even though no food was present.
310
nephridia
Structure in earthworms for excretion of the nitrogen waste urea.
311
tropic hormones
Hormones that stimulate other glands to release their hormones.
312
greenhouse effect
Carbon dioxide and water vapor in the air absorb much of the infrared radiation reflecting off Earth, causing the average temperature on Earth to rise.
313
plasma
Liquid portion of the blood.
314
Eohippus
A transition fossil that demonstrates that the ancient horse is an ancestor of the modern horse, Equus.
315
Structures that are remnants of an earlier active structure, such as the appendix. They are evidence that animals have evolved.
vestigial structures
316
vessel elements
Structures that, along with tracheas, make up xylem.
317
Platelets.
thrombocytes
318
isotonic
Solutions containing equal concentrations of solute.
319
gradualism
The theory that organisms descended from a common ancestor gradually, over a long period of time, in a linear of branching fashion.
320
Special proteins that wrap around DNA, forming chromatin network.
histones
321
osmosis
Diffusion of water across a membrane.
322
Plant hormones that promote stem and leaf elongation.
gibberellins
323
Insoluble in water.
hydrophobic (Hydrophobic substances are non polar.)
324
conjugation
A primitive form of sexual reproduction where individuals exchange genetic material.
325
thermophiles
Organisms that thrive in very high temperatures, like in the hot springs in Yellowstone Park or in deep-sea hydrothermal vents.
326
companion cells
Make up phloem vessels, along with sieve tube elements.
327
cytosol
Semiliquid portion of the cytoplasm.
328
The diploid (2n) generation of a plant.
sporophyte
329
buffers
Chemicals that resist a change in pH.
330
A mutation where one nucleotide is substituted for a correct one in the DNA strand.
base-pair substitution
331
biotic potential
The maximum rate at which a population could increase under ideal conditions.
332
An inheritance pattern characterized by blending of traits. An example is crossing an animal with black fur with one with white fur, producing offspring with gray fur.
incomplete dominance
333
Single, large root.
taproot (Like a carrot.)
334
Symbiotic relationship where both organisms benefit (+/+). An example is the bacteria that live in the human intestine and that produce vitamins.
mutualism
335
Band of muscle at the bottom of the stomach that keeps food in the stomach long enough to be digested.
pyloric sphincter
336
G3P
(Also glyceraldehyde-3-phosphate or PGAL.) First sugar produced by photosynthesis.
337
vacuoles
Organelles in cells whose function is storage.
338
A chromosomal fragment breaks off and reattaches to its original chromosome but in the reverse orientation.
inversion
339
sinuses
Cavities in the body for exchange of fluid. Called hemocoel in grasshoppers.
340
Phenylketonuria
An inherited disease characterized by the inability to break down the amino acid phenylalanine. Requires elimination of phenylalanine from diet, otherwise serious mental retardation will result.
341
ground state
Condition of an electron when it is not excited. It is in its lowest energy level.
342
Structures, such as a bat's wing and a fly's wing, that have the same function but not the same underlying structure. The similarity is merely superficial and reflects adaption to a similar environment. Analogous structures are NOT evidence of a common origin or common ancestry.
analogous structures
343
punctuated equilibrium
Theory that proposes that new species appear suddenly after long periods of stasis. Replaced gradualism theory in popularity.
344
A population whose members have the potential to interbreed in nature and produce viable, fertile offspring.
species
345
urethra
Tube that carries semen and urine in males. In females it carries only urine.
346
coelomate
An animal that has a true coelom, or body cavity. All chordates are coelomates.
347
amylase
Enzyme that digests starch.
348
pioneer organisms
The first to colonize a barren environment in primary ecological succession.
349
Red blood cells.
erythrocytes
350
gibberellins
Plant hormones that promote stem and leaf elongation.
351
Part of the nervous system that controls voluntary muscles.
somatic system
352
apoptosis
Programmed cell death.
353
Chromosomes other than the sex chromosomes. Humans normally have 44 in each body cell.
autosomes
354
Alternate forms of a gene. For example, there are two alleles for height in pea plants, tall and dwarf.
alleles
355
An animal consisting of three cell layers. This includes every animal more sophisticated than flatworms.
triploblastic
356
Innate, highly stereotypical behavior, which once begun is continued to completion, no matter how useless or silly looking.
fixed action pattern
357
histamine
An important chemical in the immune system that triggers vasodilation (enlargement of blood vessels), which increases blood supply to an area. Histamine is also responsible for the symptoms of the common cold.
358
The mutual evolutionary set of adaptations of two interacting species.
coevolution
359
A mutation where a piece of a gene, or chromosome, is lost.
deletion
360
Having less concentration of solute than another solution.
hypotonic
361
Organisms that thrive in very high temperatures, like in the hot springs in Yellowstone Park or in deep-sea hydrothermal vents.
thermophiles
362
theory of endosymbiosis
This theory states that cell organelles, like mitochondria, were once tiny, free-living prokaryotic organisms that took up permanent residence inside larger prokaryotic organisms.
363
Structures located on the tips of a gametophyte plant and that produce sperm.
antheridia
364
Cells that contain internal membranes. The opposite of prokaryotic cells.
eukaryotes
365
carpel
Female part of the flower, produce the female gametophytes, ova. Each carpel consists of an ovary, stigma, and style. Also called the pistil.
366
Plant tissue that is always dividing. An example is cambium tissue.
meristem tissue
367
Vessels in plants that carry water and nutrients from the soil to the rest of the plant.
xylem
368
The three-nucleotide sequence associated with tRNA.
anticodon
369
Misfolded proteins that cause mad cow disease.
prions
370
purines
The nucleotides adenine and guanine.
371
sex-linked
Traits carried on the X chromosome.
372
Theory that the first cells on Earth were anaerobic, heterotrophic prokaryotes.
heterotroph hypothesis
373
food chain
Pathway along which food is transferred from one trophic or feeding level to another.
374
Digestive hormone that stimulates the pancreas to release bicarbonate to neutralize acid in the duodenum.
secretin
375
Substance that does the dissolving.
solvent
376
carbon fixation
Incorporation of carbon dioxide into a sugar. It occurs during the cyclical process called the Calvin cycle.
377
law of independent assortment
Best demonstrated by the dihybrid cross. A cross that is carried out between two individuals hybrid for two or more traits that are not on the same chromosome -- the resulting phenotype ratio is 9:3:3:1.
378
karyotype
Procedure that analyzes the size, shape, and number of chromosomes.
379
heat of vaporization
The amount of energy required to change a specified amount of liquid into a gas. Water has a high heat of vaporization.
380
Type of evolution where unrelated species occupying the same environment and subjected to similar selective pressures show similar adaptations. The classic example is the whale (a mammal) and the fish.
convergent evolution
381
Having a chromosome in triplicate instead of duplicate.
trisomy (Down syndrome is caused by trisomy of the 21st chromosome.)
382
gastrulation
The process by which a blastula develops into a gastrula with the formation of three embryonic layers.
383
antennae
(Also called accessory pigments.) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
384
limiting factors
Those factors that limit population growth. They are divided into two categories, density-dependent and density-independent factors.
385
pseudopods
Means "false feet." This is how amoeba and white blood cells move from place to place.
386
chorion
Membrane that lies under the shell of an egg and allows for diffusion of respiratory gases between the outside environment and the inside of the shell.
387
eukaryotes
Cells that contain internal membranes. The opposite of prokaryotic cells.
388
The maximum rate at which a population could increase under ideal conditions.
biotic potential
389
inversion
A chromosomal fragment breaks off and reattaches to its original chromosome but in the reverse orientation.
390
operant conditioning
Trial and error learning.
391
mRNA
(Also messenger RNA.) Carries messages directly from DNA in the nucleus to the cytoplasm during protein synthesis.
392
Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation.
electron transport chain or ETC
393
nucleolus
Where components of ribosomes are synthesized. This is a prominent region within the nucleus of a cell that is not dividing.
394
coenzymes
Vitamins that assist in the normal functioning of enzymes.
395
law of segregation
During the formation of gametes, the traits carried on homologous chromosomes separate.
396
System by which we name and classify all organisms, living and extinct.
taxonomy
397
Enzymatic breakdown, hydrolysis, of food so it is small enough to be assimilated into the body.
digestion
398
yolk sac
Membrane that encloses the yolk of an egg; food for the growing embryo.
399
ETC
(Also electron transport chain.) Consistes of a series of molecules within the crustal membrane of mitochondria that provides the energy to phosphorylate ADP into ATP during oxidative phosphorylation
400
Made of the protein actin and help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division or the amoeba to move by sending out pseudopods.
microfilaments
401
plasmodesmata
Openings in cell walls of plants for the passage of materials from one cell to another.
402
Programmed cell death.
apoptosis
403
Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies that those at lower trophic levels.
biological magnification
404
Molecules that are chains of repeating units.
polymers (Proteins and DNA are examples.)
405
Single supercontinent on ancient Earth that slowly separated into seven separate continents over the course of 150 million years. This is evidence of the theory of continental drift.
Pangaea
406
Gaseous plant hormone that promotes fruit ripening.
ethylene
407
cofactors
Minerals that assist in the normal functioning of enzymes.
408
metabolism
The sum total of all the life functions.
409
synthesis
Combining of small molecules or substances into larger, more complex ones.
410
The first 10 inches of small intestine. Where all digestion is completed.
duodenum
411
Structure in earthworms for excretion of the nitrogen waste urea.
nephridia
412
An inherited disease with onset early in life that is caused by lack of the enzyme necessary to break down lipids necessary for normal brain function. It is common in Ashkenazi Jews and results in seizures, blindness, and early death.
Tay-Sachs disease
413
cohesion tension
The attraction of like molecules to stick together. Water molecules tend to stick together because they exhibit strong cohesion tension.
414
An inheritance pattern where both traits show at once. In humans, a person who has 2 different genes for blood type, A and B, has type AB blood.
codominance
415
mutualism
Symbiotic relationship where both organisms benefit (+/+). An example is the bacteria that live in the human intestine and that produce vitamins.
416
Structure in the membranes of mitochondria and chloroplasts where ATP is formed.
ATP synthetase
417
Tube that carries semen and urine in males. In females it carries only urine.
urethra
418
Best demonstrated by the dihybrid cross. A cross that is carried out between two individuals hybrid for two or more traits that are not on the same chromosome -- the resulting phenotype ratio is 9:3:3:1.
law of independent assortment
419
Plant cells that have very thick primary and secondary cell walls fortified with lignin.
sclerenchyma cells (Their function is purely support.)
420
Cyclical process that produces sugar. It occurs during the light-independent reactions.
Calvin cycle
421
gastrovascular cavity
Gastrocoel, primitive digestive cavity in hydra.
422
Includes all the organisms in a given area as well as the abiotic (nonliving) factors with which they interact.
ecosystem
423
Type of plastid that carries out photosynthesis.
chloroplasts
424
amnion
Membrane that encloses the embryo in protective amniotic fluid.
425
anticodon
The three-nucleotide sequence associated with tRNA.
426
Structure found in freshwater protista, like paramecia and amoeba, that pumps out excess water that diffuses inward because the organisms live in an environment that is hypotonic.
contractile vacuole
427
objective lens
The sense on a light microscope that is closest to the stage.
428
telomeres
Special nonsense nucleotide sequences (TTAGGG) located at the ends of chromosomes that repeat thousands of times. These ends protect the DNA during cell division.
429
gross primary productivity
Amount of energy converted to chemical energy by photosynthesis per unit in an ecosystem.
430
System of transport channels within the cytoplasm of a eukaryotic cell.
endoplasmic reticulum
431
Division of the cytoplasm. In animal cells, a cleavage furrow forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each other. In plant cells, a cell plate from down the middle of the cell.
cytokinesis
432
cation
A positive ion.
433
centromere
Specialized region of a chromosome that holds two sister chromatids together.
434
Organisms that contain both female and male sex organs.
hermaphrodites
435
Make up phloem vessels, along with sieve tube elements.
companion cells
436
contractile vacuole
Structure found in freshwater protista, like paramecia and amoeba, that pumps out excess water that diffuses inward because the organisms live in an environment that is hypotonic.
437
insulin
Hormone released by the pancreas that lowers blood sugar.
438
exons
Expressed sequences of DNA. DNA that codes for particular polypeptides.
439
Liquid portion of the blood.
plasma
440
DNA
The heritable material, passed from parent to offspring.
441
Vase-shaped body.
polyp
442
Trial and error learning.
operant conditioning
443
Cell organelle that consists of digestive (hydrolytic) enzymes and is the principal site of intracellular digestion in the cell.
lysosome
444
nondisjunction
An error that sometimes happens during meiosis in which homologous chromosomes fail to separate as they should.
445
chloroplasts
Type of plastid that carries out photosynthesis.
446
Pangaea
Single supercontinent on ancient Earth that slowly separated into seven separate continents over the course of 150 million years. This is evidence of the theory of continental drift.
447
pyrimidines
Class of nucleotides, includes thymine and cytosine.
448
pedigree
Family tree that indicates the phenotype of one trait being studied for every member of a family.
449
Stingers found in cnidocytes of cnidarians.
nematocysts
450
Primitive digestive cavity in hydra.
gastrovascular cavity or gastrocoel
451
The development of an egg without fertilization. The resulting adult is haploid.
partheonogenesis
452
Type of cell division for growth and repair that produces two genetically identical daughter cells with the same chromosome number as the parent cell. Consists of four phases: prophase, metaphase, anaphase, and telophase.
mitosis
453
A machine that spins mashed tissue so quickly that it separates the homogenate into separate pellets of different organelles.
ultracentrifuge
454
Loss of water from a leaf of a plant through stomates.
transpiration
455
The first to colonize a barren environment in primary ecological succession.
pioneer organisms
456
prokaryotes
Cells that have no internal membranes or internal organelles, like nuclei or mitochondria.
457
irritability
Ability to respond to stimuli.
458
cytoplasm
The entire region between the nucleus and plasma membrane.
459
bottleneck effect
Natural disasters such as fire, earthquake, and flood reduce the size of a population non selectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under or overrepresented compared with the original population.
460
Changing environmental conditions give rise to the type of natural selection. One phenotype replaces another in the gene pool.
directional selection
461
Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
ribosomal RNA or rRNA
462
Type of associative learning. Pavlov trained dogs to associate the sound of a bell with food. The result of this conditioning was that dogs would salivate upon merely hearing the sound of the bell even though no food was present.
classical conditioning
463
Immunoglobins. Part of the third line of defense, the specific immune response. Each antibody molecule is a Y-shaped molecule consisting of four polypeptide chains.
antibodies
464
Onset of the menstrual cycle in girls and sperm production in boys.
puberty
465
C-4 photosynthesis
Modification for dry environments. C-4 plants exhibit modified anatomy and biochemical pathways, which enable them to minimize excessive water loss and maximize sugar production.
466
Minerals that assist in the normal functioning of enzymes.
cofactors
467
A transition fossil that demonstrates that the ancient horse is an ancestor of the modern horse, Equus.
Eohippus
468
biosphere
The global ecosystem.
469
Bonds formed between atoms where electrons are shared.
covalent bonds
470
Calvin cycle
Cyclical process that produces sugar. It occurs during the light-independent reactions.
471
covalent bonds
Bonds formed between atoms where electrons are shared.
472
Tay-Sachs disease
An inherited disease with onset early in life that is caused by lack of the enzyme necessary to break down lipids necessary for normal brain function. It is common in Ashkenazi Jews and results in seizures, blindness, and early death.
473
hypertonic
Having greater concentration of solute than another solution.
474
autotrophs
Organisms that make their own food.
475
habituation
One of the simplest forms of learning in which an animal comes to ignore a persistent stimulus so it can go about its business.
476
Changes in one gene pool of a population over generations.
microevolution
477
secondary growth
Lateral growth of a plant.
478
guard cells
Modified epithelium containing chloroplasts that control the opening and closing of the stomates by a change in shape.
479
nicotinamide adenine dinucleotide
(Also NAD.) Coenzyme that shuttles protons or electrons from glycolysis and the Krebs cycle to the electron transport chain.
480
Process by which cells take in specific molecules for which the cell has a specific receptor.
receptor-mediated endocytosis
481
The condition of an axon of a nerve when it is at rest, also known as resting potential. Sodium and potassium are pumped to opposite sides of the membrane.
polarized
482
Intake of nutrients.
ingestion
483
domain
In the newest system of classification, all organisms are classified in one of three domains, which are further divided into kingdom, phylum, class, order, family, genus, and species.
484
ectotherm
An animal, such as fish, amphibian, or reptile, that must use environmental energy or behavioral adaptations to its body temperature, cold-blooded.
485
hypotonic
Having less concentration of solute than another solution.
486
Threadlike structure that holds up the anther in the male part of a flower.
filament
487
epicotyl
Part of the embryo in a seed that becomes the upper part of the stem and leaves.
488
Anaerobic phase of cell respiration.
fermentation
489
wave of depolarization
The condition of an axon when an impulse is passing, also referred to as an action potential.
490
species
A population whose members have the potential to interbreed in nature and produce viable, fertile offspring.
491
System of transport within a plant consisting of openings in cell walls called plasmodesmata.
symplast
492
Attraction between molecules. One example is hydrogen bonding.
intermolecular attraction
493
Mendel's first law that states that when two organisms, each homozygous (pure) for two opposing traits are crossed, the offspring will be hybrid but while exhibit only the dominant trait. The trait that remains hidden is the recessive trait.
law of dominance
494
gametophyte
Haploid (n) generation of a plant.
495
haploid
Having half the chromosome number.
496
deoxyribonucleic acid
(Also DNA.) The heritable material, passed from parent to offspring.
497
Means "false feet." This is how amoeba and white blood cells move from place to place.
pseudopods
498
archegonia
Structures located on the tips of a gametophyte plant that produces eggs.
499
The process by which cells take in various molecules and particles by forming new vesicles made from the plasma membrane.
endocytosis
500
Organisms that obtain energy in a unique way by producing methane from hydrogen.
methanogens
501
crossing-over
A normal process in which homologous chromatids exchange genetic material. Crossover is important because it increases variation in the gametes.
502
Movement of particles against a gradient, from low concentration to high concentration. This always requires the expenditure of energy.
active transport
503
antigens
Anything that triggers an antibody response.
504
Roots that arise above ground; examples are aerial roots and prop roots.
adventitious roots
505
An important chemical in the immune system that triggers vasodilation (enlargement of blood vessels), which increases blood supply to an area. Histamine is also responsible for the symptoms of the common cold.
histamine
506
continental drift
The theory that states that the continents are floating and moving very slowly. Over millions of years, seven separate continents formed from one original continent Pangea.
507
crop
Structure in birds, insects, and earthworms, among others, for temporary storage of food.
508
filament
Threadlike structure that holds up the anther in the male part of a flower.
509
Group of individuals of one species living in one area that have the ability of interbreeding and interacting with each other.
population
510
extremophiles
Organisms that live in extreme environments, like methanogens, halophiles, and thermophiles. These organisms make up the domain Archaea.
511
Plant hormone that inhibits growth.
abscisic acid (ABA)
512
light-independent reactions
Part of photosynthesis that does NOT require light directly, only the products of light-dependent reactions. Sugar (PGAL) is the product.
513
recognition sequences or recognition sites
The specific sites on DNA that restriction enzymes cut.
514
coevolution
The mutual evolutionary set of adaptations of two interacting species.
515
One type of learning in which one stimulus becomes linked to another through experience.
associative learning
516
Tough polymer that is resistant to almost all kinds of environmental damage and that protects plants in a harsh terrestrial environment.
sporopollenin (It is found in the walls of spores and pollen from which it gets its name.)
517
transcription
The process by which DNA makes RNA.
518
Two related species that have made similar evolutionary adaptations after their divergence form a common ancestor.
parallel evolution
519
plastids
Organelles found only in plant cells; chloroplast is one example.
520
During the formation of gametes, the traits carried on homologous chromosomes separate.
law of segregation
521
Layer of tissue between two cell walls of adjacent plant cells.
middle lamella
522
The theory that living things emerge from nonliving or inmate objects.
spontaneous generation
523
The traits an organism expresses.
phenotype
524
Growth hormones in plants that are responsible for phototropism and apical dominance, the preferential growth of a plant upward (toward the sun) rather than laterally.
auxins
525
Gain of electrons.
reduction
526
stomates
Openings in leaves to exchange photosynthetic gases; water vapor, carbon dioxide, and oxygen.
527
Occurs during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles and pyretic acid converts to lactic acid, with builds up in the muscle and causes fatigue and burning.
lactic acid fermentation
528
meiosis
Type of cell division in sexually reproducing organisms that produces haploid (n) gametes.
529
collenchyma cells
Plant cells that have unevenly thickened cell walls but lack secondary cell walls. The strings of celery consist of collenchyma cells.
530
Movement of alleles into or out of a population.
gene flow
531
resolution
A measure of clarity of an image seen under a microscope.
532
primary growth
Vertical growth of a plant.
533
decomposer
Organisms that play a vital role in the ecosystem and that recycle dead organic mater. Examples are bacteria and fungi.
534
Wavelengths of light that humans can see: 380 nm to 750 nm.
visible spectrum
535
substrate level phosphorylation
Process by which ATP is produced as a special enzyme moves a phosphate from one molecule to ADP. How energy is produced during glycolysis and the Krebs cycle.
536
chromoplasts
Type of plastid that stores pigments that are responsible for the bright colors in fruit and flowers.
537
heterotroph hypothesis
Theory that the first cells on Earth were anaerobic, heterotrophic prokaryotes.
538
abscisic acid (ABA)
Plant hormone that inhibits growth.
539
oxytocin
Hormone secreted by the posterior pituitary that stimulates the uterus and causes contractions during labor.
540
Sac outside the abdominal cavity that holds the testes. The cooler temperature there enables sperm to survive.
scrotum
541
Consist of two centrioles at right angles to each other. Important during cell division into animal cells.
centrosome
542
Bacteria that causes the most ulcers.
Heliobacter pylori
543
locomotion
Moving from place to place.
544
microfilaments
Made of the protein actin and help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division or the amoeba to move by sending out pseudopods.
545
codon
The three-nucleotide sequence associated with mRNA.
546
homeostasis
Internal stability.
547
vagina
Birth canal.
548
Tiny, spikelike projections on some leaves for protection.
trichomes
549
Formation of sperm by meiotic cell division.
spermatogenesis
550
Radioactive isotopes, those that are decaying as they emit particles from the nucleus.
radioisotopes
551
Pacemaker of the heart.
sinoatrial (SA) node
552
The enzyme that catalyzes the elongation of the new DNA strands during replication.
DNA polymerase
553
replication bubbles
Sections of DNA where the two strands separate in order to enable replication to occur rapidly. There are thousands of these bubbles along the DNA molecule, which speed up the process of replication along the giant human DNA molecule.
554
Part of the embryo in a seed that becomes the lower part of the stem and the roots.
hypocotyl
555
accessory pigments
(Also called antennae.) Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
556
Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species. Homologous structures are evidence of divergent evolution.
divergent evolution
557
In the nephron of the kidneys, a process by which most of the water and solutes (glucose, amino acids, and vitamins) that initially entered the tubule during filtration are transported back into the capillaries and, thus, back to the body.
reabsorption
558
A mutation in one nucleotide on DNA.
point mutation (Sickle cell anemia is caused by a point mutation.)
559
pistils
Female part of the flower. Each pistil consists of an ovary, stigma, and style. Also called carpel.
560
sporopollenin
Tough polymer that is resistant to almost all kinds of environmental damage and that protects plants in a harsh terrestrial environment. It is found in the walls of spores and pollen from which it gets its name.
561
There are more than two allelic forms of a gene.
polygenic (Examples include height or hair color in humans. The trait exhibits a multitude of variation.)
562
Substance that is dissolved in a solvent.
solute
563
Carbon dioxide and water vapor in the air absorb much of the infrared radiation reflecting off Earth, causing the average temperature on Earth to rise.
greenhouse effect
564
halophiles
Organisms that thrive in environments with high salt concentrations like Utah's Great Salt Lake.
565
testcross
Backcross. A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or hybrid (Bb). The organism of unknown genotype is crossed with a recessive individual.
566
aneuploidy
Any abnormal condition of the chromosomes.
567
polygenic
There are more than two allelic forms of a gene. Examples include height or hair color in humans. The trait exhibits a multitude of variation.
568
taproot
Single, large root like a carrot.
569
somatic system
Part of the nervous system that controls voluntary muscles.
570
Exact or detailed.
precision (often expressed as a degree of precision, i.e., to the hundredths.)
571
The process that occurs during the light-dependent reactions in which water is ripped apart to provide electrons to replace those lost by chlorophyll a. Oxygen is released.
photolysis
572
White blood cells.
leukocyte
573
mesoderm
The middle layer of an embryo that develops into blood, bones, and muscle.
574
Removal of metabolic waste.
egestion
575
ribosomal RNA
(Also rRNA.) Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
576
Hormones that stimulate other glands to release their hormones.
tropic hormones
577
The most common lethal genetic disease in the United States, 1 out of 25 Caucasians is a carrier. Characterized by build-up of extracellular fluid in the lungs and digestive tract.
cystic fibrosis
578
endocytosis
The process by which cells take in various molecules and particles by forming new vesicles made from the plasma membrane. There are three examples: pinocytosis, phagocytosis, and receptor-mediated endocytosis.
579
Change in the gene pool due chance. Two examples are the bottleneck effect and the founder effect.
genetic drift
580
frameshift
An error in the DNA in which the entire reading frame is altered. This can be caused by an insertion or deletion.
581
endosperm
Food for the growing embryo in a monocot seed. The cells that make up the endosperm are triploid (3n).
582
parenchyma cells
Traditional-looking plant cell. Have a primary cell wall that is thin and flexible but lack a secondary cell wall.
583
mesoglea
The middle layer of a two-layered animal, like sponges or hydra, which holds the two layers together.
584
restriction enzymes
Extracted from bacteria; they cut DNA at specific recognition sequences or sites, such as GAATTC.
585
solvent
Substance that does the dissolving. In a solution of salt and water, the salt is the solute and the water is the solvent.
586
malpighian tubule
Structures in grasshoppers for removal of the nitrogenous waste uric acid.
587
Separation by mountain ranges, canyons, rivers, lakes, or glaciers, may cause significant isolation.
geographic isolation
588
menopause
Cessation of the menstrual cycle.
589
oxidation
Loss of electrons.
590
hypocotyl
Part of the embryo in a seed that becomes the lower part of the stem and the roots.
591
A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or hybrid (Bb). The organism of unknown genotype is crossed with a recessive individual.
testcross or backcross
592
spindle fibers
Made of microtubules, these assist in cell division.
593
Cellular process by which cells take in large dissolved molecules, referred to as cell drinking.
pinocytosis
594
Photosynthetic antennae pigments. They are orange and yellow.
carotenoids
595
The type of natural selection increases the numbers of extreme types in a population at the expense of intermediate forms.
disruptive selection
596
The amount of energy required to start a reaction.
energy of activation
597
A positive ion.
cation
598
The nucleotides adenine and guanine.
purines
599
Male part of the flower, consists of anther and filament.
stamen
600
disruptive selection
The type of natural selection increases the numbers of extreme types in a population at the expense of intermediate forms.
601
egestion
Removal of metabolic waste.
602
Animals that maintain a consistent body temperature. Examples are birds, mammals, and some reptiles.
homeotherm or endotherm
603
Sophisticated process in which the responses of the organism are modified as a result of experience.
learning
604
Gross primary productivity minus the energy used by the primary producers for respiration.
net primary productivity
605
gene flow
Movement of alleles into or out of a population.
606
Having greater concentration of solute than another solution.
hypertonic
607
endotherm
An animal that uses metabolic energy to maintain constant body temperature; warm-blooded.
608
Enzyme that digests starch.
amylase
609
turgid
A property of plant cells, swollen.
610
rhizobium
Symbiotic bacterium that lives in the nodules on roots of specific legumes and that fixes nitrogen gas from the air into a form of nitrogen the plant requires.
611
ultracentrifuge
A machine that spins mashed tissue so quickly that it separates the homogenate into separate pellets of different organelles.
612
Removal of metabolic waste.
excretion
613
antibodies
Immunoglobins. Part of the third line of defense, the specific immune response. Each antibody molecule is a Y-shaped molecule consisting of four polypeptide chains.
614
Having half the chromosome number.
haploid
615
A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or heterozygous (Bb).
backcross or testcross
616
cytokinins
Plant hormones that stimulate cell division and cytokinesis.
617
Birth canal.
vagina
618
Aggressive behavior.
agonistic behavior
619
gizzard
Structure in birds, insects, and earthworms where mechanical digestion of food occurs.
620
fission
Division of an organism into two new cells. Reproduction in protists.
621
A primitive form of sexual reproduction where individuals exchange genetic material.
conjugation
622
community
Consists of all the organisms living in one area.
623
pith
Specialized region in the root of a plant for storage.
624
Organisms that live in extreme environments, like methanogens, halophiles, and thermophiles. These organisms make up the domain Archaea.
extremophiles
625
Learning that occurs during a sensitive or critical period in the early life of an individual and is irreversible for the length of that period.
imprinting
626
Theory that proposes that new species appear suddenly after long periods of stasis. Replaced gradualism theory in popularity.
punctuated equilibrium
627
Division of an organism into two new cells. Reproduction in protists.
fission
628
Plasma without the clotting factors.
serum
629
oviduct
(Also fallopian tube.) Where fertilization occurs. After ovulation, the egg moves through the oviduct to the uterus.
630
Cells that house the stingers in cnidarians.
cnidocytes
631
alveolus (alveoli, plural)
Microscopic air sacs in the lung where diffusion of the respiratory gases, oxygen and carbon dioxide, occurs.
632
Male gonads; the site of sperm formation.
testes (testis, singular)
633
Membrane that encloses the embryo in protective amniotic fluid.
amnion
634
Part of the nervous system that controls automatic functions, such as heart and breathing rate.
autonomic nervous system
635
An organism with extra sets of chromosomes (3n, 4n, etc.)
polyploid (Commonly occurs in plants.)
636
stroma
Part of the chloroplasts that holds the grana.
637
cutin
Waxy coating ont eh leaves that helps prevent excess water loss from the plant.
638
light-dependent reactions
Part of photosynthesis that requires light, produces ATP, and releases oxygen.
639
Organism that causes disease.
pathogen
640
epiglottis
Flap of cartilage in the back of the throat that directs food to the esophagus.
641
Part of photosynthesis that requires light, produces ATP, and releases oxygen.
light-dependent reactions
642
The modern technique of taking DNA from two sources and combining them into one molecule or cell.
recombinant DNA
643
A mutation where one nucleotide inserts itself into an existing strand. This mutation can cause a frameshift.
insertion
644
intermolecular attraction
Attraction between molecules. One example is hydrogen bonding.
645
Food for the growing embryo in a monocot seed. The cells that make up the endosperm are triploid (3n).
endosperm
646
centrosome
Consist of two centrioles at right angles to each other. Important during cell division into animal cells.
647
Archaeopteryx
An intermediate fossil that shows both reptile and bird characteristics.
648
vestigial structures
Structures that are remnants of an earlier active structure, such as the appendix. They are evidence that animals have evolved.
649
transpiration
Loss of water from a leaf of a plant through stomates.
650
When there are more than two allelic forms of a gene. For example in humans, there are more than 2 alleles for blood type. There are A, B, and O.
multiple alleles
651
dicotyledon
Plant whose seed easily breaks in two.
652
sodium-potassium pump
Elaborate molecule that sits within neuron membranes and pumps sodium and potassium ions across the membrane.
653
A cell-free, automated technique by which a piece of DNA can be rapidly copied or amplified.
polymerase chain reaction (Useful in genetic engineering.)
654
partheonogenesis
The development of an egg without fertilization. The resulting adult is haploid.
655
learning
Sophisticated process in which the responses of the organism are modified as a result of experience.
656
biotic factor
Includes all the organisms with which an organism might react in an ecosystem.
657
plasmolysis
Cell shrinking, occurs when a cell is in a hypertonic environment.
658
Malthus
Published a treatise on population growth, disease, and famine in 1798 that influenced Darwin in the development on his theory of natural selection. Malthus stated that populations tend to grow exponentially, to overpopulate, and to exceed their resources.
659
hydrogen bonding
An intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.
660
Cells that, along with vessel elements, make up xylem.
tracheids
661
Inheritance is influenced by the sex of the individual carrying the trait.
sex-influenced trait
662
Growth of a plant toward or away from a stimulus.
tropism
663
Part of the embryo in a seed that becomes the upper part of the stem and leaves.
epicotyl
664
cnidocytes
Cells that house the stingers in cnidarians.
665
The attraction of like molecules to stick together. Water molecules tend to stick together because they exhibit strong cohesion tension.
cohesion tension
666
Symbiotic relationship in which one organism benefits and one is not affected by the other organism (+/o).
commensalism
667
The sense on a light microscope that is closest to the stage.
objective lens
668
Cells that have no internal membranes or internal organelles, like nuclei or mitochondria.
prokaryotes
669
An animal, such as fish, amphibian, or reptile, that must use environmental energy or behavioral adaptations to its body temperature, cold-blooded.
ectotherm
670
The innermost layer of an embryo, which develops into the viscera or the digestive system.
endoderm
671
The three-nucleotide sequence associated with mRNA.
codon
672
middle lamella
Layer of tissue between two cell walls of adjacent plant cells.
673
Heliobacter pylori
Bacteria that causes the most ulcers.
674
translocation
A fragment of a chromosome becomes attached to a non homologous chromosome.
675
pseudocoelomate
An animal with a false coelom. An example is a roundworm.
676
An animal that has no true coelom. Flatworms are an example.
acoelomate
677
Process that separates large molecules of DNA on the basis of their rate of movement through an agarose gel in an electric field.
gel electrophoresis
678
transformation
A phenomenon in bacteria. They have the ability to transform themselves by transferring genetic factors from one bacteria cell to another.
679
Hormone released by the pancreas that raises blood sugar.
glucagon
680
Part of photosynthesis that does NOT require light directly, only the products of light-dependent reactions. Sugar (PGAL) is the product.
light-independent reactions
681
colon
Another name for the large intestine.
682
heterotrophs
Organisms that must take in all their nutrients.
683
Structures that, along with tracheas, make up xylem.
vessel elements
684
precision
Exact or detailed; often expressed as a degree of precision, i.e., to the hundredths.
685
tropism
Growth of a plant toward or away from a stimulus.
686
biotechnology
The branch of science that uses recombinant DNA techniques for practical purposes, also called genetic engineering.
687
The process by which a blastula develops into a gastrula with the formation of three embryonic layers.
gastrulation
688
The flow of molecules from a higher concentration to a lower concentration. There are two types: simple and facilitated.
diffusion
689
ingestion
Intake of nutrients.
690
Pathway along which food is transferred from one trophic or feeding level to another.
food chain
691
energy of activation
The amount of energy required to start a reaction.
692
junk
Noncoding regions of DNA. Most of the human genome consists of noncoding regions.
693
A limit to the number of individuals that can occupy one area at a particular time.
carrying capacity (K)
694
sporophyte
The diploid (2n) generation of a plant.
695
This theory states that cell organelles, like mitochondria, were once tiny, free-living prokaryotic organisms that took up permanent residence inside larger prokaryotic organisms.
theory of endosymbiosis
696
analogous structures
Structures, such as a bat's wing and a fly's wing, that have the same function but not the same underlying structure. The similarity is merely superficial and reflects adaption to a similar environment. Analogous structures are NOT evidence of a common origin or common ancestry.
697
solute
Substance that is dissolved in a solvent.
698
PGAL
(Also glyceraldehyde-3-phosphate or G3P.) First sugar produced by photosynthesis.
699
The most important buffer in human blood. It is responsible for keeping the pH of the blood at 7.4.
bicarbonate ion
700
phycobilins
A photosynthetic pigment.
701
Plant cells that have unevenly thickened cell walls but lack secondary cell walls. The strings of celery consist of collenchyma cells.
collenchyma cells
702
diastole
Relaxation of the ventricles of the heart. Normal diastolic pressure is 120 mm Hg.
703
The process by which DNA makes RNA.
transcription
704
microevolution
Changes in one gene pool of a population over generations.
705
Nonliving factors in an ecosystem. They include: temperature, water, sunlight, wind, rocks, and soil.
abiotic factors
706
Formation of ova by meiotic cell division.
oogenesis
707
transfer RNA
(Also tRNA.) Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
708
Those factors that limit population growth.
limiting factors (They are divided into two categories, density-dependent and density-independent factors.)
709
ectoderm
The outermost layer of an embryo, which develops into skin and nervous system.
710
bicarbonate ion
The most important buffer in human blood. It is responsible for keeping the pH of the blood at 7.4.
711
Openings in cell walls of plants for the passage of materials from one cell to another.
plasmodesmata
712
sepals
Outermost circle of leaves around a flower that are green and closely resemble ordinary leaves.
713
transport
Intake and distribution of substances in cells or tissue, NOT the same thing as locomotion.
714
Digestive hormone that stimulates sustained secretion of gastric juice from the stomach.
gastrin
715
bile
Chemical produced in the liver and released from the gallbladder that emulsifies fats. It is NOT an enzyme.
716
The name given to two or more atoms joined by a covalent bond.
molecule
717
Soluble in water.
hydrophilic (Hydrophilic substances are either polar or ionic.)
718
Organisms that make their own food.
autotrophs
719
cardiac sphincter
Band of muscle at the top of the stomach that keeps acidified food in the stomach from backing up into the esophagus and burning it.
720
An animal that uses metabolic energy to maintain constant body temperature; warm-blooded.
endotherm
721
Specialized region of a chromosome that holds two sister chromatids together.
centromere
722
Thick hollow tubes that make up the cilia, flagella, and spindle fibers.
microtubules
723
Ability to respond to stimuli.
irritability
724
fermentation
Anaerobic phase of cell respiration.
725
First sugar produced by photosynthesis.
glyceraldehyde-3-phosphate or PGAL or G3P
726
lactic acid fermentation
Occurs during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles and pyretic acid converts to lactic acid, with builds up in the muscle and causes fatigue and burning.
727
vesicles
Small vacuoles.
728
codominance
An inheritance pattern where both traits show at once. In humans, a person who has 2 different genes for blood type, A and B, has type AB blood.
729
An intermediate fossil that shows both reptile and bird characteristics.
Archaeopteryx
730
specific heat
Amount of heat that must be absorbed in order for 1 gram of a substance to change its temperature by 1 degree Celsius.
731
DNA polymerase
The enzyme that catalyzes the elongation of the new DNA strands during replication.
732
receptor-mediated endocytosis
Process by which cells take in specific molecules for which the cell has a specific receptor.
733
Molecules that consist of many monosaccharides joined together.
polysaccharides (Starch and chitin are examples.)
734
A combination of reduction and oxidation reactions.
redox
735
binomial nomenclature
System of taxonomy that we use today, developed by Carl von Linne. In this system, every organism has a two-part name, like Homo sapiens.
736
myosin
Myofilaments that make up the thick filaments in skeletal muscle.
737
The same internal bone structure, although the function of each varies. Examples: the wing of a bat, the lateral fin of a whale, and the human arm. If organisms have homologous structures, they have a common ancestor.
homologous structures
738
style
Long, usually thin stalk of the pistil of a flower.
739
radioisotopes
Radioactive isotopes, those that are decaying as they emit particles from the nucleus.
740
Symbiotic relationship (+/-) where one organism, the parasite, benefits while the host is harmed.
parasitism
741
Metabolic processes that produce energy (adenosine triphosphate or ATP) for all the life processes.
respiration
742
Haploid (n) generation of a plant.
gametophyte
743
glucagon
Hormone released by the pancreas that raises blood sugar.
744
origins of replication
Special sites where replication begins in eukaryotic cells.
745
prostate gland
Large gland that secretes semen directly into the urethra
746
Process that provides most of the energy (ATP) produced during cell respiration.
oxidative phosphorylation
747
Organelles in cells whose function is storage.
vacuoles
748
abiotic factors
Nonliving factors in an ecosystem. They include: temperature, water, sunlight, wind, rocks, and soil.
749
The global ecosystem.
biosphere
750
mycorrhizae
Symbiotic structures consisting of the plant's roots intermingled with the hyphae (filaments) of a fungus, which greatly increase the quantity of nutrients that a plant can absorb.
751
This is how ATP is produced during oxidative phosphorylation. Protons only flow through the special ATP synthetase channels and transfer energy to molecules of ATP.
chemiosmosis
752
homologous structures
The same internal bone structure, although the function of each varies. Examples: the wing of a bat, the lateral fin of a whale, and the human arm. If organisms have homologous structures, they HAVE a common ancestor.
753
excretion
Removal of metabolic waste.
754
Process that occurs in the nephron where nutrients and wastes diffuse from the glomerulus into Bowman's capsule.
filtration
755
thrombocytes
Platelets.
756
The theory that states that the continents are floating and moving very slowly. Over millions of years, seven separate continents formed from one original continent Pangea.
continental drift
757
notochord
A rod that extends the length of the body and serves as a flexible axis. This is a characteristic of all chordates.
758
A rod that extends the length of the body and serves as a flexible axis. This is a characteristic of all chordates.
notochord
759
duodenum
The first 10 inches of small intestine. Where all digestion is completed.
760
point mutation
A mutation in one nucleotide on DNA. Sickle cell anemia is caused by a point mutation.
761
Sections of DNA where the two strands separate in order to enable replication to occur rapidly. There are thousands of these bubbles along the DNA molecule, which speed up the process of replication along the giant human DNA molecule.
replication bubbles
762
hydrophobic
Insoluble in water. Hydrophobic substances are non polar.
763
Contraction of the ventricles of the heart. Normal systolic pressure is 120 mm Hg.
systole
764
filtration
Process that occurs in the nephron where nutrients and wastes diffuse from the glomerulus into Bowman's capsule.
765
Series of inner membranes in mitochondria where cell respiration occurs.
cristae
766
An inherited disease caused by the absence of one or more proteins necessary for normal blood clotting.
hemophilia
767
glycolysis
The anaerobic phase of aerobic respiration. One molecule of glucose breaks apart into two molecules of pyruvate.
768
systole
Contraction of the ventricles of the heart. Normal systolic pressure is 120 mm Hg.
769
Plant hormones that stimulate cell division and cytokinesis.
cytokinins
770
omnivores
Animals that normally eat both meat and vegetables in their diet.
771
Small vacuoles.
vesicles
772
The process by which certain cells convert pyretic acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen.
alcohol fermentation
773
Strand of mRNA before it is processed
initial transcript
774
Bonds between atoms that form by transferring electrons.
ionic bonds
775
autosomes
Chromosomes other than the sex chromosomes. Humans normally have 44 in each body cell.
776
alleles
Alternate forms of a gene. For example, there are two alleles for height in pea plants, tall and dwarf.
777
The condition of an axon when an impulse is passing, also referred to as an action potential.
wave of depolarization
778
ethylene
Gaseous plant hormone that promotes fruit ripening.
779
trisomy
Having a chromosome in triplicate instead of duplicate. Down syndrome is caused by trisomy of the 21st chromosome.
780
rRNA
(Also ribosomal RNA.) Structural RNA that is synthesized in the nucleolus. Along with proteins, it makes up the ribosome.
781
fixed action pattern
Innate, highly stereotypical behavior, which once begun is continued to completion, no matter how useless or silly looking. FAP's are initiated by external stimuli called sign stimuli.
782
vas deferens
Duct that carries sperm during ejaculation from the testes to the penis.
783
The kind of genes an organism has.
genotype
784
Large gland that secretes semen directly into the urethra
prostate gland
785
The entire region between the nucleus and plasma membrane.
cytoplasm
786
Cell organelle that produces ATP. Present in both plants and animals.
mitochondrion
787
Confers or cone-bearing trees.
gymnosperms
788
Where fertilization occurs. After ovulation, the egg moves through to the uterus.
fallopian tube or oviduct
789
respiration
Metabolic processes that produce energy (adenosine triphosphate or ATP) for all the life processes.
790
Natural disasters such as fire, earthquake, and flood reduce the size of a population non selectively, resulting in a loss of genetic variation. The resulting population is much smaller and not representative of the original one. Certain alleles may be under or overrepresented compared with the original population.
bottleneck effect
791
Another name for meiosis I, the division where homologous pairs separate.
reduction division
792
cytochromes
Proteins that play a key role in electron transport chains in mitochondria and chloroplasts.
793
Membranes within chloroplasts that consist of thylakoid membranes and are the sites of the light-dependent reactions of photosynthesis.
grana
794
Molecules that assist in photosynthesis by capturing and passing on photons of light to chlorophyll a and expanding the range of light that can be used to produce sugar. Examples are chlorophyll b and the carotenoids.
antennae or accessory pigments
795
Another name for the large intestine.
colon
796
Hormone secreted by the posterior pituitary that stimulates the uterus and causes contractions during labor.
oxytocin
797
global warming
Increase in average temperature of Earth. It is due to the greenhouse effect.
798
stele
Vascular cylinder in a plant root.
799
The middle layer of a two-layered animal, like sponges or hydra, which holds the two layers together.
mesoglea
800
law of dominance
Mendel's first law that states that when two organisms, each homozygous (pure) for two opposing traits are crossed, the offspring will be hybrid but while exhibit only the dominant trait. The trait that remains hidden is the recessive trait.
801
The process in which homologous chromosomes pair up. This occurs during prophase I.
synapsis
802
Waxy coating ont eh leaves that helps prevent excess water loss from the plant.
cutin
803
recombinant DNA
The modern technique of taking DNA from two sources and combining them into one molecule or cell.
804
carotenoids
Photosynthetic antennae pigments. They are orange and yellow.
805
mutation
Any change in a gene or chromosome.
806
lipid
One type of organic molecule. It consists of one glycerol plus three fatty acids.
807
Special nonsense nucleotide sequences (TTAGGG) located at the ends of chromosomes that repeat thousands of times. These ends protect the DNA during cell division.
telomeres
808
Type of plastid that stores starch.
leucoplast
809
The amount of energy required to change a specified amount of liquid into a gas. Water has a high heat of vaporization.
heat of vaporization
810
half-life
Amount of time it takes for a radioactive isotope to decay to half its mass.
811
A replicated chromosome consists of two fo these, where one is an exact copy of the other.
sister chromatids
812
A photosynthetic pigment.
phycobilins
813
scrotum
Sac outside the abdominal cavity that holds the testes. The cooler temperature there enables sperm to survive.
814
monocotyledon
Plant whose seed does not break into two parts. An example is corn.
815
pharynx
Throat.
816
methanogens
Organisms that obtain energy in a unique way by producing methane from hydrogen.
817
spontaneous generation
The theory that living things emerge from nonliving or inmate objects.
818
Female part of the flower, produce the female gametophytes, ova. Each one consists of an ovary, stigma, and style.
carpel or pistil
819
deletion
A mutation where a piece of a gene, or chromosome, is lost.
820
Chemicals that absorb light energy and use it to carry out photosynthesis. Examples are chlorophyll a, chlorophyll b, carotenoids, and phycobilins.
photosynthetic pigments
821
tracer
Radioactive substance that can be used to track a substance as it moves through an organism or through a metabolic pathway. They can be used research or as a diagnostic tool in medicine.
822
sessile
Nonmoving.
823
oxidative phosphorylation
Process that provides most of the energy (ATP) produced during cell respiration.
824
Splitting off of new individuals from existing ones. How reproduction occurs in hydra.
budding
825
pyloric sphincter
Band of muscle at the bottom of the stomach that keeps food in the stomach long enough to be digested.
826
Responsible for division of the cytoplasm in animal cells; they are not present in plant cells. They consist of 9 triplets of microtubules arranged in a circle.
centrioles
827
histones
Special proteins that wrap around DNA, forming chromatin network.
828
Nonmoving.
sessile
829
actin
Protein that makes up the thin myofilaments in skeletal muscle.
830
Upside-down bowl-shaped body type.
medusa
831
base-pair substitution
A mutation where one nucleotide is substituted for a correct one in the DNA strand.
832
replication fork
A Y-shaped region where the new strands of DNA are elongating during DNA replication.
833
ATP synthetase
Structure in the membranes of mitochondria and chloroplasts where ATP is formed.
834
divergent evolution
Occurs when a population becomes isolated (for any reason) from the rest of the species and becomes exposed to new selective pressures, causing it to evolve into a new species. Homologous structures are evidence of divergent evolution.
835
reduction division
Another name for meiosis I, the division where homologous pairs separate.
836
Protein that makes up the thin myofilaments in skeletal muscle.
actin
837
releaser
Sign stimuli exchanged between members of the same species.
838
backcross
Testcross. A technique to determine whether an individual plant or animal showing the dominant trait is homozygous dominant (BB) or heterozygous (Bb).
839
Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome as proteins are synthesized.
transfer RNA or tRNA
840
allantois
Extra embryonic membrane in bird's egg. It exchanges respiratory gases to and from the embryo.
841
fallopian tube
(Also oviduct.) Where fertilization occurs. After ovulation, the egg moves through the oviduct to the uterus.
842
Asexual reproduction in a plant where a piece of the root, stem, or leaf produces an entirely new plant genetically identical to the parent plant.
vegetative propagation (Examples are grafting, cuttings, bulbs, and runners.)
843
pinocytosis
Cellular process by which cells take in large dissolved molecules, referred to as cell drinking.
844
associative learning
One type of learning in which one stimulus becomes linked to another through experience.
845
Vitamins that assist in the normal functioning of enzymes.
coenzymes
846
cristae
Series of inner membranes in mitochondria where cell respiration occurs.
847
polyp
Vase-shaped body.
848
A form of photosynthesis that is an adaptation for dry conditions. These plants keep their stomates closed during the day and open at night, the reverse of how most plants behave.
crassulacean acid metabolism or CAM
849
Membrane that lies under the shell of an egg and allows for diffusion of respiratory gases between the outside environment and the inside of the shell.
chorion
850
ecosystem
Includes all the organisms in a given area as well as the abiotic (nonliving) factors with which they interact.
