Midterm: Topics 1 - 6 Flashcards
1
Q
A suggested explanation for a problem that can be tested such as a microorganism was causing significant fish kills in a lake would be called a
A
Hypothesis
2
Q
What is the smallest, basic unit of life?
A
Cell
3
Q
Homeostasis provides what kind of environment?
A
Constant
4
Q
Organizing known species of organisms according to their evolutionary relatedness is known as
A
Taxonomy
5
Q
What is a form of logical thinking that uses related observations to come to a general conclusion?
A
Inductive reasoning
6
Q
A collection of tissues involved in a common function are known as
A
Organs
7
Q
The study of the structure and function of single-celled organisms is known as
A
Microbiology
8
Q
The type of science that is done in order to understand living things without regard to an ability to directly use that knowledge is known as
A
Basic science
9
Q
Which is a group of the same species living in a geographical area?
A
Population
10
Q
The idea that organisms are able to “fit” their environment due to their characteristics is known as
A
Adaptation
11
Q
Which is the smallest portion of a substance that retains the properties of an element?
A
Atom
12
Q
The negative subatomic particles that orbit the nucleus are
A
Electrons
13
Q
Water is an example of a(n)
a. atom
b. ion
c. compound
d. mixture
e. element
A
Compound
14
Q
How do hydrophobic molecules react with water?
A
Repelled by
15
Q
Starch is
a. a polypeptide
b. a polysaccharide
c. a lipid
d. a nucleic acid
A
b. a polysaccharide
16
Q
Carbon usually forms how many bonds with other atoms?
A
4
17
Q
Which are NOT macromolecules (also known as polymers)?
a. proteins
b. cellulose
c. amino acids
d. nucleic acids
A
c. amino acids
18
Q
Which of the following includes all the others?
a. sucrose
b. glucose
c. cellulose
d. starch
e. carbohydrate
A
e. carbohydrate
19
Q
What kind of bond exists between two amino acids in a protein?
A
peptide
20
Q
A chemical buffer
a. makes things shiny
b. equalizes ions
c. provides hydrogen ions or removes them to maintain pH
d. puts up a sphere of hydration between ions
A
c. provides hydrogen ions or removes them to maintain pH
21
Q
The idea that mitochondria and chloroplasts likely came from a larger prokaryotic cell engulfing and enslaving a smaller prokaryotic cell is known as the _____ theory.
A
Endosymbiotic
22
Q
Which of the following has a cell wall made up of peptidoglycan?
a. bacteria
b. plants
c. animals
d. archaea
e. all of these
A
bacteria
23
Q
________ is responsible for making lipids (and membrane vesicles).
A
Smooth ER
24
Q
________ are specialized storage structures in plants (can hold water for rigidity).
A
Central vacuole
25
_________ is (are) primarily responsible for moving things from one part of the cell to another.
Vesicles
26
_______ is the “powerhouse” of the cell, known for making ATP.
Mitochondria
27
_______ is the “post office” of the cell, known for sorting and sending proteins and lipids to their final destination.
Golgi
28
Prokaryotes do NOT have _____.
Membrane bound nuclei
29
_____ is a cell part responsible for maintaining cell shape, internal organization, and cell movement.
Cytoskeleton
30
Which type of junctions allows small molecules to pass between cells?
Gap
31
All of the following are associated with endocytosis EXCEPT
a. secretion of cell products
b. endocytic vesicles
c. phagocytosis
d. plasma membrane going in
e. bulk-phase uptake of materials
a. secretion of cell products
32
To be able to invade host cells, viruses need something to attach to, usually a cell membrane
Receptor
33
The concentration of glucose inside of a cell is higher than the concentration outside of that cell, yet glucose continues to enter the cell. This is an example of
Active transport
34
A charge difference across a membrane, like what happens with K+ and Na+, is known as the
Electrochemical gradient
35
Which of the following accounts for the cell membrane keeping out polar substances from the cell?
a. the hydrophilic phospholipid heads
b. the integral membrane proteins
c. the hydrophobic fatty acid tails of the phospholipids
d. the cytoskeleton
C. The hydrophobic fatty acid tails of the phospholipids
36
The carrier molecules (transporters) used in active transport are
Proteins
37
A single-celled freshwater organism is transferred to salt water. Which of the following is likely to happen?
a. the cell bursts
b. salt is pumped out of the cell
c. shrinking
d. enzymes flow out of the cell
e. all of these
c. shrinking
38
Which of the following is NOT likely to diffuse through a membrane?
a. glucose
b. oxygen
c. water
d. carbon dioxide
a. glucose
39
Which statement is NOT true?
a. membranes are often perforated by proteins that extend through both sides of the membrane.
b. some membranes have proteins with channels or pores that allow for the passage of hydrophilic molecules.
c. polar substances have an easier time passing directly through membranes than nonpolar substances do.
d. the current concept of a membrane can be best summarized by the fluid mosaic model.
E)
The lipid bilayer serves as a hydrophobic barrier between two fluid regions.
c. polar substances have an easier time passing directly through membranes than nonpolar substances do.
40
Which of the following would not affect diffusion?
a. molecular weight
b. concentration
c. color
d. temperature
c. color
41
In an enzyme-catalyzed reaction such as X + Y = Z, Z is the
Product
42
Intermediates are associated with which of the following?
a. antioxidants
b. dead cells
c. free energy
d. metabolic pathways
d. metabolic pathways
43
_______ reactions use energy to build complex molecules.
Anabolic
44
Which of the following binds to an allosteric site in order to change the shape of enzyme so that the substrate won't bind to the active site?
a. cofactor
b. suppressor
c. activator
d. inhibitor
d. inhibitor
45
Typically, what molecule is causing feedback inhibition in a metabolic pathway?
The end product of the pathway
46
Enzymes increase the rate of reaction by lowering what kind of energy?
Activation
47
Essentially, the first law of thermodynamics says that
energy can neither be created nor destroyed
48
The second law of thermodynamics states that
energy tends to become increasingly disorganized
49
A reaction that releases free energy is known as a(n) _____ reaction.
exergonic
50
When a substrate binds to the active site of an enzyme, it changes the shape of the enzyme to help the reaction proceed. What is this model called?
induced fit
51
Plants need which of the following to directly carry out photosynthesis?
a. H2O
b. CO2
c. O2
d. lipid
e. both H2O AND CO2
e. both H2O and CO2
52
The final electron acceptor in aerobic respiration is
O2
53
Pyruvate is regarded as the end product of
glycolysis
54
Glycolysis typically takes place in the
cytoplasm
55
The oxygen released in photosynthesis comes from
water
56
Which of the following conditions is NOT required for Calvin Cycle?
a. carbon dioxide is present
b. the plant is exposed to light
c. RuBP is present
d. enough ATP
e. enough NADPH
b. the plant is exposed to light
57
The correct sequence of the three processes listed below is:
I – glycolysis II – oxidative phosphorylation III – citric acid cycle
I – III – II or glycolysis - citric acid cycle - oxidative phosphorylation
58
An organism that can produce its own food is called a(n)
autotroph
59
The citric acid cycle takes place in the
mitochondria
60
Four of the five answers listed below are catabolic processes for carbon compounds. Select the EXCEPTION.
a. Calvin cycle
b. citric acid cycle
c. fermentation
d. cellular respiration
e. glycolysis
Calvin cycle
61
Define biology
the study of life
62
Properties of life (8 characteristics that define life)
order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing.
63
Order
consists of one or more cells
64
Positive response to stimuli
movement towards a stimulus
65
Negative response to stimuli
movement away from a stimulus
66
Reproduction in single-celled organisms
duplicate DNA and divide it equally, divides to form two new cells
67
Reproduction in multi-cellular organisms
produce specialized reproductive cells that form new individuals,genes containing DNA are passed to offspring
68
What is adaptation?
"fit" to the environment, consequence of evolution by natural selection
69
What do adaptations enhance of individuals exhibiting them?
reproductive potential
70
Are adaptations constant or do they vary?
adaptations vary
71
What do gene instructions direct?
cellular growth and development
72
Why do offspring exhibits characteristics of their parents?
From the DNA or genes that get passed on during reproduction
73
What is regulation as a property of life?
complex organisms requiring multiple regulatory mechanisms to coordinate internal functions
Example: circulatory system carries oxygen throughout the body, delivers nutrients to cells
74
What is homeostasis?
the ability of an organism to maintain constant internal conditions
75
What is energy processing as a property of life?
All organisms use a source of energy for their metabolic activities.
Example: plants capturing light energy from the Sung and converting it into chemical energy in food
76
What is the smallest and most fundamental unit of matter?
atom
77
What is an atom?
nucleus surrounded by electrons
78
What do atoms combine to form?
a molecule
79
What is a molecule?
chemical structure consisting of at least two atoms held together by a chemical bond
80
What are macromolecules?
large molecules formed by combining monomers, biologically important
Example: DNA
81
What are monomers?
molecules, smaller units
82
What are organelles?
small structures in cells that perform specialized functions
83
What is the smallest fundamental unit of structure and function in living organisms?
cell
84
Why aren't viruses considered living?
they are not made of cells; they have to invade and hijack a living cell
85
What are prokaryotic cells?
single-celled organisms lacking organelles surrounded by a membrane and do not have nuclei surrounded by nuclear membranes
86
What are eukaryotes?
organisms with membrane-bound organelles and nuclei
87
What are organs?
collections of tissues grouped together based on a common function
88
Are organs found in:
a. plants only
b. plants and animals
c. animals only
b. plants and animals
89
What is an organ system?
functionally related organs
90
What are organisms?
individual living entities
91
What are microorganisms?
single-celled prokaryotes and single-celled eukaryotes
92
What is a basic unit of matter consisting of a dense central nucleus surrounded by a loud of negatively charged electrons?
atom
93
What is a molecule?
a phospholipid, composed of many atoms
94
What is an organelle?
structures that perform functions within a cell
95
Differentiate between organisms, populations, and communities
in a park, each person is an organism. together all the people make up a population. all the plant and animal species in the park compromise a community
96
Describe the levels of organization from smallest to largest
atom - molecule - organelles - cells - tissues - organs - organ systems - organisms - populations - communities - ecosystem - biosphere
97
Which of the following statements is false?
a. tissues exist within organs which exist within organ systems
b. communities exist within populations which exist within ecosystems
c. organelles exist within cells which exist within tissues
d. communities exist within ecosystems which exist in the biosphere
b. communities exist within populations which exist within ecosystems
98
What is applied science?
a form of science that solves real-world problems
99
what is basic science?
science that seeks to expand knowledge regardless of the short-term application of that knowledge
100
What is a control?
a part of an experiment that does not change during the experiment
101
What is deductive reasoning?
a form of logical thinking that uses a general statement to forecast specific results
102
What is descriptive science?
A form of science that aims to observe, explore and find things out
103
Define falsifiable
able to be disproven by experimental results
104
What is a population?
collectively, all the individuals of a species living within a specific area
105
What is a community?
set of populations inhabiting a particular area
106
What is an ecosystem?
all the living things in a particular area together with abiotic, or non-living, parts of that environment
107
What is the biosphere?
collection of all ecosystems, represents zones of life on earth include land, water and portions of he atmosphere
108
What is evolution?
the process of gradual change during with new species arise from older species
109
How many levels are in the current taxonomic system?
8 levels
110
What are the 8 levels of the current taxonomic system?
species, genus, family, order, class, phylum, kingdom, domain
111
What are the 3 domains of life?
Eukarya, Archae, and the Bacteria
112
What organisms are in the domain eukarya?
fungi, plants, animals, and protists
113
What are archae?
single-celled organisms without nuclei, includes many extremophiles living in harsh environments
114
What are bacteria?
single-celled organisms without nuclei
115
Are classifications permanent?
No, they will change when new information becomes available
116
What are bionomial names?
consists of genus name (capitalized) and the species name (lowercase)
117
What is a phylogenetic tree?
diagram showing evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both
118
What do the internal nodes of the phylogenetic tree represent?
represent ancestors and points of evolution when an ancestor diverged to form two new species
119
What does the length of the branch on a phylogenetic tree represent?
estimate of relative time
120
define neurobiology
study of the nervous system
121
define paleontology
study of life's history by fossils
122
define zoology
study of animals
123
define botany
study of plants
124
define ecologist
specialist studying the interactions of organisms in their environments
125
define physiologists
specialist studying the workings of cells, tissues, and organs
126
define science
knowledge about the natural world
127
What is the scientific method?
method of research with defined steps that include experiments and careful observation
128
What is a hypothesis?
suggested explanation for an event, which can be tested
129
What is a scientific theory?
generally accepted, thoroughly tested and confirmed explanation for a set of observations or phenomena
130
What are scientific laws?
describe how elements of nature will behave under certain specific conditions
131
What are natural sciences?
fields of science related to the physical world and its phenomena and processes
132
What are life sciences?
study living things
133
What are physical sciences?
study non-living matter
134
What is inductive reasoning?
form of logical thinking that uses related observations to arrive at a general conclusion
135
What is qualitative data?
descriptive
136
What is quantitative data?
consisting of numbers
137
What is deductive reasoning?
form of logical thinking that uses a general principle or law to forecast specific results
138
What does descriptive science aim to do?
to observe, explore, and discover
139
Hypothesis-based science
begins with a specific question or problem and a potential answer or solution to be tested
140
What are the steps of the scientific methods?
make an observation, ask a question, form a hypothesis , make a prediction, do an experiment, analyze results, determine if data supports hypothesis, report results or try again
141
What is a variable?
any part of the experiment that can vary or change during the experiment
142
What is a control?
part of the experiment that does not change
143
Define soluble
dissolves in water
144
Define insoluble
does not dissolve in water
145
key building blocks of the chemicals found in living things
carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus
146
Matter
occupies space and has mass
147
What are elements?
substances that cannot be broken down or transformed chemically into other substances
148
Smallest component of an element that retains all of the chemical properties of that element
atom
149
All atoms contain protons, electrons, and neutrons except:
Hydrogen which only has one proton and one electron
150
What is a proton?
positively charged particle that resides in the nucleus
151
What is the nucleus?
the core of an atom
152
What is the mass and charge of a proton?
mass of 1 charge of +1
153
What is an electron?
negatively charged particle that travels in the space around the nucleus
154
What is the mass and charge of an electron?
no mass, charge of -1
155
What is a neutron?
reside in the nucleus on atom
156
What is the mass and charge of a neutron?
mass of 1, no charge
157
What is the mass of an atom equal to?
the number of protons and neutrons of that atom
158
What is the atomic number of an element?
equal to the number of protons that the element contains
159
What is the mass number?
number of protons plus the number of neutrons in that element
160
What is the periodic table of elements?
chart of elements including atomic number and relative atomic mass of each element
161
What are isotopes?
different forms of the same element with the same number of protons but different number of neutrons
162
What elements have naturally occurring elements
carbon, potassium and uranium
163
Most common isotope of carbon
Carbon-12
164
What are radioactive isotopes?
an isotope that spontaneously emits particles or energy to form a more stable element
165
What is the half-life of an isotope?
the time it takes for half of the original concentration of an isotope to decay to its more stable form
166
How many electrons can be hold in the closest shell
2 electrons
167
What shell is filled first with electrons?
the closest shell to the nucleus
168
How many electrons can the second shell hold?
8 electrons
169
How many electrons can the third shell hold?
8 electrons
170
How are electrons arranged in the 2nd and 3rd shells?
arranged in four pairs
171
How are electron shells filled?
one position in each pair is filled with an electron before any pairs are completed
172
What do the rows of the periodic table represent?
rows correspond to the number of shells that the elements within that row have
173
What do the columns of the periodic table represent?
Increasing numbers of electrons from left to right
174
When is an atom most stable?
When its outermost shell is full
175
What are chemical bonds?
interactions between two or more of the same or different elements that result in the formation of molecules
176
What is the octet rule?
states that the outermost shell of an element with a low atomic number can hold eight electrons
177
What can an element do to satisfy the octet rule?
donate, accept, or share electrons
178
what is an ion?
an atom or compound that does not contain equal number of protons and electrons, and therefore has a net charge
179
What are cations?
positive ions that are formed by losing electrons
180
What are anions?
negative ions that are formed by gaining electrons
181
What is an electron transfer?
movement of electrons from one element to another
182
Name 4 types of bonds
ionic, covalent, hydrogen bonds, and van der Waals interations.
183
Which bonds have strong interactions?
ionic and covalent bonds
184
What kind of charge will an element have if it accepts an electron?
negative charge
185
What is an ionic bond?
a chemical bond that forms between ions of opposite charges
186
What are covalent bonds?
a type of strong bond between two or more of the same or different elements; forms when electrons are shared between elements
187
Which bond(s) dissociate in water?
a. ionic bonds
b. covalent bonds
c. both
a. ionic bonds
188
What type of bonds are used to form water?
covalent bonds
189
What are the two types of covalent bonds?
polar and non-polar
190
What are non-polar covalent bonds?
bonds formed between two atoms of the same element or between different elements that share the electrons equally
191
What are polar covalent bonds?
a type of covalent bond in which electrons are pulled toward one atom and away from another, resulting in a slightly positive and slightly negative charged regions of the molecule
192
Does oxygen have a slightly positive or negative charge in water?
slightly negative because the electrons spend more time near the oxygen nucleus
193
Does hydrogen have a slightly positive or negative charge in water?
slightly positive charge because electrons spend more time near oxygen than hydrogen nuclei
194
What are two frequently occurring weak bonds?
hydrogen and van der Waals interactions
195
What is a hydrogen bond?
A weak bond between partially positively charged hydrogen atoms and partially negatively charged elements or molecules
196
What are van der Waals interactions?
a weak attraction or interaction between molecules caused by slightly positively charge or slightly negatively charged atoms
197
Where do van der Waals interactions occur?
between polar, covalently bound, atoms in different molecules
198
How does MRI imaging works?
by subjecting hydrogen nuclei to fluctuating magnetic fields which cause them to emit their own magnetic field
199
How much of the body is made up of water?
approx. 60-70%
200
Define hydrophilic
a substance that dissolves in water; water-loving
201
Define hydrophobic
a substance that does not dissolve in water; water-fearing
202
What is temperature?
a measure of the motion (kinetic energy) of molecules
203
Define evaporation
the release of water molecules from liquid water to form water vapor
204
Example of a solvent
water
205
What is a solvent?
a substance capable of dissolving another substance
206
What are spheres of hydration?
charged particles form hydrogen bonds with a surrounding layer of water molecules, also known as hydration shells
207
Why is water an effective solvent
due to its polarity
208
What is cohesion?
the intermolecular fores between water molecules caused by the polar nature of water, creates surface tension
209
What is surface tension?
the cohesive force at the surface of a body of liquid that prevents the molecules from seperating, capacity of a substance to withstand rupture when placed under tension or stress
210
What is adhesion?
the attraction between water molecules and other molecules
211
What is the pH of a solution?
a measure of its acidity or alkalinity
212
What is litmus paper?
paper treated with natural water-soluble dye so it can be used as a pH indicator
213
What does the pH test measure
the amount of hydrogen ions that exists in a given solution
high concentration = low pH
low concentration = high pH
214
What does a change of one unit on the pH scale represent
a change in the concentration of hydrogen ions by a factor of 10
215
What is the pH of pure water
neutral (7)
216
What pH levels are acidic?
anything below 7
217
What pH levels are alkaline?
anything above 7
218
What is the pH of blood?
7.4 slightly alkaline
219
What is the pH of the stomach?
1 - 2 highly acidic
220
What are acids?
substances that provide hydrogen ions (H+) and lower pH
221
What are bases?
substances that provide hydroxide ions (OH-) and raise pH
222
Window of the pH scale of cells in the body
7.2 - 7.6
223
What do buffers readily absorb?
excess H+ or OH-, this allows for the body to maintain pH levels
224
Buffer system of the human body
carbonic acid (H2CO3) and bicarbonate (HCO3-) anion
225
What are large molecules necessary for life that are built from smaller organic molecules?
biological macromolecules
226
What are the 4 major classes of biological macromolecules?
carbohydrates, lipids, proteins and nucleic acids
227
Are biological macromolecules organic or inorganic?
organic because they contain carbon
228
"foundation" element for molecules in living things
carbon
229
how many covalent bonds can carbon form
4
230
natural sources of carbohydrates
grains, fruits, and vegetables
231
what is the formula representing carbohydrates
(CH2O)n, where n = number of carbon atoms in the molecule
232
Define monosaccharides
simple sugars
Example: glucose
233
form of monosaccharides
exist as linear chain or as ring-shaped molecules
234
formula for glucose
C6H12O6
235
glucose, galactose, and fructose are all found in
carbohydrates
236
galactose and fructose are
a. monosaccharides
b. polysaccharides
c. disaccharides
a. monosaccharides
237
What are disaccharides?
form when two monosaccharides undergo a dehydration reaction
238
Lactose maltose and sucrose are
a. monosaccharieds
b. polysaccharides
c. disaccharides
c. disaccharides
239
Most common disaccharide
sucrose
240
What is a polysaccharide
a long chain of monosaccharides linked by covalent bonds
241
starch, glycogen, cellulose, and chitin are
a. monosaccharieds
b. polysaccharides
c. disaccharides
b. polysaccharides
242
What is starch
stored form of sugars in plants made up of amylose and amylopectin
243
What is glycogen?
storage form of glucose in humans and other vertebrates, made up of monomers of glucose
244
What is cellulose?
makes up cell walls of plants, abundant natural biopolymer
245
define dietary fiber
cellulose passing through our digestive system
246
What breaks down cellulose into glucose monomers
cellulase
247
What is chitin?
nitrogenous carbohydrate
248
Are lipids polar or non-polar molecules?
non-polar molecules
249
Where do cells store energy for long-term use
fats
250
What are fats, oils, waxes, phospholipids, and steroids?
Lipids
251
What does a fat molecule consist of?
two main components - glycerol and fatty acids
252
What are fatty acids composed of?
long chain of hydrocarbons to which an acidic carboxyl group is attached
253
How many fatty acids are in a triglyceride?
three
254
What are saturated fatty acids
fatty acids saturated with hydrogen; hydrogen atoms attached to the carbon skeleton is maximized
255
What are unsaturated fatty acids
fatty acids containing a double bond in the hydrocarbon chain
256
What are oils
unsaturated fats at room temperature
257
What is a monounsaturated fat
one double bond in the molecule
258
what is a polyunsaturated fat
more than one double bond in the molecule
259
How are saturated fats packed?
tightly, solid at room temperature
260
Are unsaturated or saturated fats better for you?
unsaturated fats because the improve blood cholesterol while saturated fats contribute to plaque formation in the arteries
261
What type of fats are made through artifical hydrogenation
trans-fats
262
What are essential fatty acids?
fatty acids required but not synthesized by the human body such as omega-3 fatty acids
263
What are omega-3 fatty acids important for in the body?
brain function and normal growth and development
264
What are phospholipids?
a major constituent of the membranes of cells; composed of two fatty acids and a phosphate group attached to the glycerol backbone
265
Which layer of the phospholipid faces the water?
phosphate group
266
which layer of the phospholipid faces away from the water?
the fatty acid side
267
What kind of structure do steroids have?
four, linked carbon rings - several with short tails
268
Are steroids hydrophilic or hydrophobic?
hydrophobic
269
Cholesterol is a
a. protein
b. steroid
c. lipid
d. carbohydrate
b. steroid
270
What is a protein?
a biological macromolecule composed of one or more chains of amino acids
271
How many different types of amino acids are there?
20
272
What are enzymes?
catalysts in biochemical reactions, usually proteins
273
Function of enzymes
to break molecular bonds, to rearrange bonds, or to form new bonds
274
What are hormones?
chemical signaling molecules, usually proteins or steroids, secreted by an endocrine gland or group of endocrine cells that act to control or regulate specific physiolgical processes
275
Define denaturation
the loss of shape in a protein as a result of changes in temperature, pH, or exposure to chemicals
276
What are amino acids
monomers that make up proteins
277
What is the composition of an amino acid
central carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), and a hydrogen atom. + a variable R group
278
What is the difference in structure of different amino acids?
R group
279
What determines the chemical nature of an amino acid
R group
280
What kind of bonds do amino acids use to bond to one another?
peptide bonds
281
What is a polypeptide?
polymer of amino acids, long chain of amino acids linked by peptide bonds
282
When polypeptide or polypeptides have combined together, have a distinct shape, and have a function we refer to them as:
proteins
283
What are the 4 levels of protein structure
primary, secondary, tertiary and quaternary
284
What is the primary protein structure?
sequence of a chain of amino acids - determined by gene that encodes the protein
285
What is the secondary protein structure?
hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern
286
Most common structures of secondary protein structures
alpha - helix, and beta - pleated
287
describe the structure of the alpha helix
bonds form between every fourth amino acid and cause a twist in the amino acid chain
288
describe the structure of the beta - pleated
pleats are formed by hydrogen bonding and align parallel to each other, and hydrogen bonds form between the same pairs of atoms on each of the aligned amino acids
289
What types of proteins are alpha-helix and beta-pleated commonly found in?
globular and fibrous proteins
290
What is the tertiary protein structure?
three-dimensional folding pattern of a protein due to side chain interactions
291
What is the quaternary protein structure?
protein consisting of more than one amino acid chain
292
What are the 2 main types of nucleic acids?
DNA & RNA
293
What monomers make up DNA and RNA?
nucleotides
294
What is a nucleotide composed of?
nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group
295
What is the structure of DNA
two strands of nucleotides in a double-helical structure
296
Where are the nitrogenous bases of DNA stacked?
in the interior of the structure
297
In DNA, what lies on the outside of each strand?
alternating sugar and phosphate groups
298
What kind of bonds are used in DNA base pairing
hydrogen bonds
299
The smallest unit of a living thing is a
cell
300
Bacteria and archae cells are classified as
prokarytic
301
What cells are classified as eukaryotic
animal, plant, fungal, and protist
302
What is a microscope?
instrument that magnifies an object
303
Microscope part that changes the orientation of the image
Example: specimen that is right-side up and facing right on the microscope will appear upside-down and facing left
optics of the lenses of a light microscope
304
How does a light microscope work?
Visible light passes through and is bent by the lens system allowing the user to see the specimen
305
What is an advantage of using a light microscope?
advantageous for viewing living organisms, however stains must be used to distinguish cell components
306
Define magnification
degree of enlargement of an object
307
What is resolving power?
the ability of a microscope to allow the eye to distinguish two adjacent structures as seperate
308
What microscope has a lower magnification than light microscopes and provides a three-dimensional view of a specimen?
Dissection microscope
309
Dissecting microscopes are designed to give a
magnified and clear view of tissue structure as well as the anatomy of the whole organism
310
Define binocular
two separate lens systems
311
Does the orientation change the view of the specimen in a dissecting microscope?
No, the optics correct the image to appear as if being seen by the naked eye
312
Instead of a beam light, this microscope uses a beam of electrons
electron microscope
313
A disadvantage of an electron microscope is that
living cells cannot be viewed
314
In the electron microscope, the electron beam moves best in a
vacuum
315
In a scanning electron microscope, how does the beam of electrons move?
back and forth across a cell's surface, showing the details of cell surface characteristics by reflection
316
What microscope provides details of a cell's internal structures?
transmission electron microscope
317
What are cytotechnologists?
professionals who study cells through microscopic examinations and other laboratory tests
318
What does the unified cell theory state?
all living things are composed of one or more cells, that the cell is the basic unit of life, and that all new cells arise from existing cells
319
Name the four components all cells share
plasma membrane, cytoplasm, DNA, ribosomes
320
What is the plasma membrane?
outer covering that separates the cell's interior from its surrounding environment
321
What is the cytoplasm?
jelly-like region within the cell where other cellular components are found
322
What is DNA?
genetic material of the cell
323
What are ribosomes?
particles that synthesize proteins
324
What is a prokaryotic cell?
unicellular organism that lacks a nucleus, or any other membrane-bound organelle
325
Where is DNA found in prokaryotic cells?
in the central part of the cell in the nucleoid
326
What is the nucleoid?
A darkened region in the central part of the prokaryotic cell
327
What is the cell wall of bacteria composed of?
peptidodoglycan
328
Why is bacteria different from Archae and eukaryotes?
cell wall made of peptidoglycan, compromised of sugars and amino acids, and many have a polysaccharide capsule
329
Functions of the cell wall
extra layer of protection, helps the cell maintain its shape, and prevents dehydration
330
Function of capsule
enables the cell to attach to surfaces in its environment
331
What is a eukaryotic cell?
a cell that has membrane-bound nucleus and other membrane-bound organelles that have specialized functions
332
What is an organelle?
a compartment or sac in the cell that have specialized functions
333
Are prokaryotic or eukaryotic cells bigger?
Eukaryotic cells are significantly bigger
334
As the cell becomes ________, it becomes more difficult for the cell to aquire sufficient materials to support the processes inside the cell.
larger
335
A plasma membrane is composed of
a phospholipid bilayer with embedded proteins that separate internal contents of the cell from its surrounding environment
336
What are microvilli?
tiny hair-like folds in the plasma membrane
337
What increases surface area of plasma membrane?
microvilli
338
Where are microvilli typically found in the human body?
lining the small intestine
339
Describe celiac disease
immune response to gluten that damages microvilli - afflicted individuals cannot absorb nutrients leads to malnutrition cramping diarrhea
340
the consistency of cytoplasm
semi-solid
341
What is cytosol
the gel-like material of the cytoplasm in which cell structures are suspended
342
What is the cystoskeleton of a cell
the network of protein fibers
343
Function of the cytoskeleton
maintains cell shape, secures organelles in specific positions, allows movement within the cell and enables unicellular organisms to move
344
Name the 3 types of fibers within the cytoskeleton:
microfilaments (actin filaments), intermediate filaments, and microtubules
345
Microfilaments are often found in
muscle cells
346
Keratin is an example of a(n)
intermediate filament
347
Are microfilaments thick or thin?
thin
348
Are microtubules thick or thin?
thick
349
Function of microtubules
guide organelle movement
350
What do microtubules do during cell division
pull chromosomes to their poles
351
What are the structural components of flagella and cilia?
microtubules
352
What functions as a microtubule-organizing center?
the centrosome
353
What role do centrioles play in cell division?
they pull duplicated chromosomes to opposite ends of the dividing cell
354
What is the flagella?
long, hair-like structures that extend from the plasma membrane
355
Function of flagella
move the entire cell
356
When present where are cilia located?
they extend along the entire surface of the plasma membrane
357
What are cilia?
short, hair-like structures that are used to move entire cells or move substances alon gthe outer surface of the cell
358
What is the endomembrane system composed of?
nuclear envelope, lysosomes, and vesicles, the endoplasmic reticulum and Golgi apparatus, and the plasma membrane (although it isn't in the cell) because it interacts with these organelles
359
The nucleus houses the cell's DNA in the form of
chromatin
360
What does the DNA do in the cell?
Directs the synthesis of ribosomes and proteins
361
What is the nuclear envelope?
a double-membrane structure that constitutes the outermost portion of the nucleus
362
What are the inner and outer membranes of the nuclear envelope composed of?
phospholipid bilayers
363
What is the purpose of the pores punctuated in the nuclear envelope?
controls the passage of ions, molecules, and RNA between the nucleoplasm and the cytoplasm
364
What are chromosomes composed of?
chromatin
365
What does DNA and proteins form
chromatin
366
How many chromosomes are in the human body?
46
367
What is the nucleolus?
the darkly staining body within the nucleus that is responsible for assembling ribosomal subunits
368
Function of the nucleolus
aggregates the ribosomal RNA with associated proteins in order to assemble the ribosomal subunits that are then transported through the nuclear pores into the cytoplasm
369
What is the endoplasmic reticulum (ER)?
series of interconnected membranous tubules
370
Function of ER
modifies proteins and synthesizes lipids
371
What is the lumen or cisternal space?
the hollow portion of the ER tubules
372
What is on the surface of the RER?
ribosomes
373
What does the RER do?
makes phospholipids for cell membranes, modifies proteins
374
RER is abundant in cells that secrete:
proteins, such as the liver
375
Function of smooth endoplasmic reticulum
synthesis of carbohydrates, lipids, and steroid hormones; detoxification of medications and poisons; alcohol metabolism; and storage of calcium ions
376
Function of the golgi apparatus
sorts, packages, tags, and distributes lipids or proteins
377
What is the golgi apparatus?
a series of flattened membranous sacs
378
What do transport vesicles do with lipids or proteins?
deposit their contents into other parts of the cell where they will be used
379
What do secretory vesicles do?
Fuse with plasma membrane and release their contents outside of the cell
380
What type of cells have an abundant number of golgi?
cells that engage in a great deal of secretory activity
381
What additional role does the golgi play in plant cells?
role of synthesizing polysaccharides
382
What part of the cell is known as the "garbage disposal"?
Lysosome
383
What is a lysosome?
an organelle in an animal cell that functions as the cell's digestive component
384
What does the lysosome break down?
proteins, polysaccharides, lipids, nucleic acids, and worn-out organelles
385
What is phagocytosis?
a section of the plasma membrane of the macrophage invaginates (folds in) and engulfs a pathogen
386
What are vesicles and vacuoles?
membrane-bound sacs that function in storage and transport
387
What is the difference between vesicles and vacuoles?
vacuoles are somewhat larger, and the membrane of a vacuole does not fuse with the membranes of other cellular components
388
What are ribosomes?
cellular structures responsible for protein synthesis
389
Where are ribosomes abundant?
in immature red blood cells
390
What is the mitochondria?
an oval-shaped, double-membrane organelles that is the "powerhouses" of a cell responsible for making ATP
391
What is cellular respiration?
the formation of ATP from the breakdown of glucose
392
Why are mitchondria different from other organelles?
they have their own ribosomes and DNA
393
What are cristae
inwardly projecting folds of the inner membrane of the mitochondria
394
What is the mitochondrial matrix?
area surrounded by the cristae or inner foldings of the mitochondria
395
What cells have a very high concentration of mitochondria?
muscle cells because they need a lot of energy to contract
396
What are peroxisomes?
small, round organelles enclosed by single membrances
397
Function of peroxisomes
carry out oxidation reactions to break down fatty acids and amino acids, detoxify poisons - example: alcohol
398
What organelles are found in animals cells that are not seen in plants?
centrioles, centrosomes, and lysosomes
399
What are some structure that plant cells have that animal cells do not?
cell wall, chloroplasts, plasmodesmata, and plastids used for storage, and a large central vacuole
400
What is a cell wall?
rigid covering external to the plasma membrane
401
Function of the cell wall
protects the cell, provides structural support, gives shape to cell
402
What cells have cell walls?
plants, fungal, protists
403
What is a plant's cell wall composed of?
cellulose
404
What is cellulose?
a polysaccharide made up of long, straight chains of glucose units
405
Why are chloroplasts different from other organelles?
they have their own DNA and ribosomes
406
define autotrophs
organism able to make their own food
407
define heterotrophs
rely on other organisms for food
408
What are thylakoids?
interconnected, stacked fluid-filled membrane sacs
409
What is a granum (grana - plural) ?
a stack of thylakoids
410
What is the stroma?
fluid enclosed by the inner membrane and surrounding the grana
411
What is chlorophyll?
green pigment found in chloroplasts
412
What is the function of chlorophyll?
captures the energy of sunlight for photosynthesis
413
What is the role of the central vacuole?
regulates the cell's concentration of water in changing environmental conditions, stores proteins in developing seed cells
414
Define turgor pressure
outward pressure caused by the fluid inside the cell
415
What is the extracellular matrix?
glycoproteins and protein collagen
416
Function of the extracellular matrix
holds the cells together to form a tissue, allows the cells within the tissue to communicate with each other
example: blood clotting
417
What are intercellular junctions?
direct contact made by cells to communicate
418
What are junctions between plant cells?
plasmodesmata
419
What are junctions between animal cells
tight and gap junctions, and desmosomes
420
What are plasmodesmata?
numerous channels that pass between the cell walls of adjacent plant cells, connecting their cytoplasm and enabling signal molecules and nutrients to be transported from cell to cell
421
What is a tight junction?
a watertight seal between two adjacent animal cells
422
What holds the cells tightly against each other in a tight junction
proteins
423
What does a tight junction prevent?
leaking of materials between cells
424
What do desmosomes do?
join two animal cells together by acting like spot welds between adjacent epithelial cells; sheet-like formation in organs and tissues such as the skin, heart, and muscles
425
What are gap junctions?
in animal cells, they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate
426
Are plasma membranes dynamic?
No they are dynamic and constantly in flux
427
The plasma membrane carriers markers that:
allow cells to recognize one another
428
The plasma membrane carriers receptors that:
are attachment sites for specific substances that interact with the cell
429
What does the fluid mosaic model describe?
the structure of the plasma membrane in which components (phospholipids, cholesterol, proteins and carbohydrates) are able to flow and change position, while maintaining the basic integrity of the membrane
430
The interior of the plasma membrane is _______, while the outside surfaces are _______.
hydrophobic, hydrophilic
431
What are integral proteins?
proteins of the plasma membrane serving as channels or pumps to move materials into or out of the cell
432
What is a glycoprotein?
protein with carbohydrate attached
433
What is a glycolipid?
lipid with carbohydrate attached
434
define selectively permeable
characteristic of a membrane that allowing some substances through but not others
435
what is passive transport
method of transporting material that does not require cell energy
436
what is a concentration gradient
an area of high concentration across from an area of low concentration
437
What is diffusion?
passive process of transport of low-molecular weight material down its concentration gradient
438
What factors affect diffusion?
concentration of gradient, mass of the molecules diffusing, temperature, and solvent density
439
What is facilitated transport?
a process by which material moves down a concentration gradient (from high to low concentration) using integral membrane proteins
440
What is osmosis?
the transport of water through a semipermeable membrane from an area of high water concentration to an area of low water concentration across a membrane
441
Why is osmosis different from other passive transports?
it only transports water
442
What does tonicity describe?
the amount of solute in a solution
443
What is osmolarity?
the measure of the tonicity of a solution
444
terms used to relate the osmolarity of a cell to the osmolarity of the extracellular fluid that contains the cells
hypertonic, hypotonic, and isotonic
445
What does hypertonic describe?
describes a solution in which exracellular fluid has higher osmolarity than the fluid inside the cell
446
What does hypotonic describe?
describes a solution in which extracellular fluid has lower osmolarity than the fluid inside the cell
447
What does isotonic describe?
describes a solution in which the extracellular fluid has the same osmolarity as the fluid inside the cell
448
What does a cell do in hypertonic solution?
the cell will shrink
449
What does a cell do in a hypotonic solution?
the cell will burst
450
What does a cell do in an isotonic solution?
stays the same because solution comes in and out of the cell at the same rate
451
What is active transport?
the method of transporting that requires energy
452
What is an electrochemical gradient?
a gradient produced by the combined forces of the electrical gradient and the chemical gradient
453
Describe primary active transport
uses ATP to move a substance into the cell and a second substance is moved out of the cell
454
Describe secondary active transport
movement of material using the energy of the electrochemical gradient established by primary active transport
455
What is endocytosis?
a type of active transport that moves substances, including fluids and particles, into a cell
456
Common characteristic of endocystosis variations
The plasma membrane of the cell invaginates, forming a pocket around the target particle. The pocket pinches off, resulting in the particle being contained in a newly created vacuole that is formed from the plasma membrane
457
What is phagocytosis?
a process that take macromolecules that the cell needs from the extracellular fluid; a variation of endocytosis
458
What is pinocytosis?
a process that takes solutes that the cell needs from the extracellular fluid: a variation of endocytosis
459
What is receptor-mediated endocytosis?
a varient of endocytosis that involves the use of specific binding proteins in the plasma membrane for specific molecules or particles
460
What is exocytosis?
a process of passing material out of a cell
461
What are bioenergetics?
the concept of energy flow through living systems
462
What is metabolism?
all the chemical reactions that take place inside cells, including those that use energy and those that release energy
463
Define anabolic
describes the pathway that requires a net energy input to synthesize complex molecules from simpler ones
464
Define catabolic
describes the pathway in which complex molecules are broken down into simpler ones, yielding energy as an additional product of the reaction
465
What is thermodynamics
the study of energy and energy transfer involving physical matter
466
In an open system,
energy can be exhanged with its surroundings
467
In a closed system,
energy cannot be exchanged with its surroundings
468
The laws of thermodynamics describe
the transfer of energy in and among all systems in the universe
469
What does the second law of thermodynamics state?
energy will always be lost as heat in energy transfers or transformations
470
What is heat energy?
the energy transferred from one system to another that is not work
471
What is entropy?
the measure of randomness or disorder within a system
472
What does high entropy mean?
high disorder, low energy
473
What is kinetic energy?
energy associated with objects in motion
474
What is potential energy?
energy with potential to do work
475
What is chemical energy?
potential energy that was in chemical bonds that were broken and released chemical energy
476
What is exergonic reactions?
describes a chemical reaction that results in products with less chemical potential energy than the reactants, plus the release of free energy
477
What is an endergonic reactions?
describes a chemical reaction that results in products that store more chemical potential energy than the reactants
478
What is activation energy?
amount of initial energy necessary for reactions to occur
479
What is an enzyme?
a molecule that catalyzes a biochemical reaction
480
What is a substrate?
a molecule on which the enzyme acts
481
What is the active site?
a specific region on the enzyme where the substrate binds
482
What is competitive inhibition?
general mechanism of enzyme activity regulation in which a molecule other than the enzyme's substrate is able to bind the active site and prevent the substrate itself from binding, thus inhibiting the overall rate of reaction for the enzyme (inhibitor competes with substrate for binding to active site)
483
What is non-competitive inhibition?
an inhibitor molecule binds to the enzyme in a location other than the allosteric site but still blocks substrate binding to the active site
484
What is allosteric inhibition?
mechanism of inhibiting enzyme action where regulatory molecule binds to a second site and initiates a conformation change in the aactive site, preventing binding with the substrate
485
What is feedback inhibition?
use of a reaction product to regulate its own further production, product inhibits an enzyme for an earlier step in the reaction series
486
What does feedback inhibition control?
production of both amino acids and nucleotides
487
What is glycolysis?
the process of breaking glucose into two three-carbon molecules with the production of ATP and NADH
488
Where does glycolysis take place in the cell?
cytoplasm
489
Describe the process of glycolysis
starts with a six-carbon, ring-shaped structure of a glucose molecule
energy is used to evenly split the six-carbon sugar into two three-carbon pyruvate molecules
ATP and NADH are produces
490
What is acetyl CoA
combination of an acetyl group derived from pyruvic acid and coenzyme A which is made from pantothenic acid (a B-group vitamin)
491
Where does the citric acid cycle take place?
in the mitochondria
492
What is the citric acid cycle?
a series of enzyme-catalyzed chemical reactions of central importance in all living cells that harvests the energy in carbon-carbon bonds of sugar molecules to generate ATP; the citric acid cycle is an aerobic metabolic pathways because it requires oxygen in later reactions to process
