Final Exam Review: Cumulative Portion Flashcards
(309 cards)
1
Q
List the six steps of the scientific method.
A
- Observation
- Question
- Hypothesis
- Prediction
- Experiment
- Conclusion
2
Q
What is a prediction?
A
What you think the result of the experiment will be, based on the hypothesis
3
Q
What is the purpose of the hypothesis?
A
It is an educated guess about the cause of a phenomenon that must make a testable prediction.
4
Q
True or false:
A hypothesis can be definitively proven correct.
A
False
It can be rejected or supported, but never definitively proven
5
Q
What is the purpose of the experiment?
A
It systematically tests the hypothesis
6
Q
What four things will a well-defined experiment include?
A
- Independent variable
- Dependent variable
- Control group
- Experimental group(s)
7
Q
All living things are descended from a…
A
Common ancestor
8
Q
True or false:
Despite being descended from a commmon ancestor, living things show wide variations in complexity, genotype, and phenotype.
A
True
9
Q
List the eight taxonomic ranks.
A
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
10
Q
A family is ____ specific than a genus.
A
Less
11
Q
List the three main tenets of cell theory.
A
- All organisms are composed of cells
- Cells are the smallest living things and the smallest unit of life.
- Cells arise only from pre-existing cells
12
Q
List the hierarchy for a unicellular organism.
A
Atom, molecule, macromolecule, organelle, cell, population, community, ecosystem, biosphere
13
Q
List the hierarchy for a multicellular organism.
A
Atom, molecule, macromolecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere
14
Q
The number of valence electrons determines an atom’s….
A
Reactivity
15
Q
The ____ states that most atoms will react in such a way that they obtain a full valence shell.
A
Octet rule
16
Q
Atoms with eight valence electrons (plus helium) are…
A
Inert
17
Q
Atoms with few valence electrons tend to…
A
Lose electrons
18
Q
Atoms with more valence electrons tend to…
A
Gain electrons
19
Q
When an atom or molecule loses electrons, it becomes….
A
A positively-charged cation
20
Q
When an atom or molecule gains electrons, it becomes…
A
A negatively-charged anion
21
Q
____ are formed when atoms or molecules share electrons.
A
Covalent bonds
22
Q
____ are formed between a metal and a nonmetal.
A
Ionic bonds
23
Q
____ are formed when atoms or molecules share a hydrogen atom.
A
Hydrogen bonds
24
Q
Which type of bonds are the strongest in biological systems?
A
Covalent
25
____ describes an atom or molecule's affinity for electrons.
Electronegativity
## Footnote
high electronegativity = wants to gain electrons ; low electronegativity = wants to lose electrons
26
List six properties of water that are fundamental for life on Earth.
1. Cohesion
2. Adhesion
3. High specific heat
4. High heat of vaporization
5. Less dense solid form
6. Universal solvent
27
Water exhibits cohesion because...
Its polarity allows it to form hydrogen bonds with other polar molecules
28
Why is cohesion important for life?
It creates surface tension, allowing water to exist as a liquid at room temperature
29
Water exhibits adhesion because...
Its polarity causes it to be attracted to other polar molecules, and adhere to anything it can form hydrogen bonds with
30
Why is adhesion important for life?
It drives capillary action
31
Water has a high specific heat because...
The hydrogen bonds formed between water molecules restrict molecular movement
32
Why is water's high specific heat important for life?
Water exists in liquid form at a wide range of temperatures since it gains and loses heat slowly
33
Water has a high heat of vaporization because...
Significant amounts of energy are required to break the hydrogen bonds between water molecules
34
Why is water's high heat of vaporization important for life?
Water remains in liquid form even at high temperatures, allowing organisms to cool themselves through sweating
35
Why is ice less dense than liquid water?
Water molecules are spaced further apart in ice than they are in liquid water.
36
Why is the fact that ice is less dense than water important for life?
Ice floats on water, enabling aquatic life to survive even when the lake/pond/river freezes over
37
Why is water considered a universal solvent?
It clusters around charged or polar molecules.
38
The pH scale measures...
The concentration of dissolved H+ ions
39
The concentration of H+ ions in a solution with a pH of 5 is ____ than in a solution with a pH of 8.
1,000 times higher
## Footnote
each number down on the pH scale represents a tenfold increase in H+
40
List the four main types of biological macromolecules.
1. Carbohydrates
2. Proteins
3. Lipids
4. Nucleic acids
41
What are the main functions of carbohydrates?
Energy storage and structural support
42
Carbohydrates are assembled from...
Monosaccharides
43
What are the main functions of proteins?
Structural support and enzymes
44
Proteins are assembled from...
Amino acids
45
What is the main function of nucleic acids?
Encode genetic information
46
Nucleic acids are assembled from...
Nucleotides
47
What are the main functions of lipids?
Energy storage, membrane structure, and cell identity/communication
48
Lipids are assembled from...
Fatty acids
49
List the seven functional groups found in biological macromolecules.
1. Hydroxyl
2. Carbonyl
3. Carboxyl
4. Amino
5. Sulfhydryl
6. Methyl
7. Phosphate
50
Carbohydrates contain which functional groups?
1. Hydroxyl
2. Carbonyl
51
Proteins contain which functional groups?
1. Hydroxyl
2. Carboxyl
3. Amino
4. Sulfhydryl
5. Methyl
52
Nucleic acids contain which functional groups?
1. Hydroxyl
2. Carbonyl
3. Amino
4. Phosphate
53
Lipids contain which functional groups?
1. Hydroxyl
2. Carboxyl
54
List the three major parts of a nucleotide.
1. Nitrogenous base
2. Phosphate group
3. Pentose sugar
55
In both DNA and RNA, the 5' carbon is attached to the...
Phosphate group
56
In both DNA and RNA, the 1' carbon is attached to the...
Nitrogenous base
57
In RNA, the 2' carbon is attached to...
Ribose
(OH)
58
In DNA, the 2' carbon is attached to...
Deoxyribose
(H)
59
In both DNA and RNA, the 3' carbon is attached to...
A hydroxyl (OH) group
60
What four nitrogenous bases are found in RNA?
1. Adenine
2. Cytosine
3. Guanine
4. Uracil
61
What four nitrogenous bases are found in DNA?
1. Adenine
2. Cytosine
3. Guanine
4. Thymine
62
Which bases are purines, and which are pyrimidines?
Purines - AG
Pyrimidines - CTU
63
A protein's identifying amino acid sidechain is called the...
R-group
64
How many different amino acids are there?
20
## Footnote
ten nonpolar, five polar w/no charge, two polar w/negative charge, three polar w/positive charge
65
A protein's ____ is its amino acid sequence.
Primary structure
66
A protein's ____ is dependent on hydrogen bonds between adjacent amino acids.
Secondary structure
67
What two shapes can the secondary structure of a protein make?
Alpha sheet and beta helix
68
A protein's ____ is three-dimensional and depends on interactions between distant amino acids.
Tertiary structure
69
A protein's ____ is formed by the association of two or more polypeptides.
Quarternary structure
70
In order to function, a protein must be...
Properly folded
71
____ occurs when a protein unfolds and inactivates.
Denaturation
72
# True or false:
It is possible for a denatured protein to re-fold if the proper environmental conditions are restored.
True
73
List six characteristics of prokaryotes.
1. Smaller than eukaryotes
2. Always unicellular
3. No internal compartments
4. Have a cell wall and/or plasma membrane
5. May have a capsule coating
6. May have pili and/or flagella
74
List five characteristics of eukaryotes.
1. Larger than prokaryotes
2. May be unicellular or multicellular
3. Have organelles
4. Have a plasma membrane
5. Have both cytoplasm and cytosol
75
What structure is believed to be unique to animal cells?
Lysosomes
76
Which structures are unique to plant cells?
1. Chloroplasts
2. Vacuoles
3. Cell walls
77
The largest organelle in eukaryotic cells is the...
Nucleus
78
RNA is made in the...
Nucleolus
79
List two major functions of the nucleus.
1. Protects DNA from damage
2. Separates RNA making from protein making
80
What is the primary function of mitochondria?
Makes ATP from sugars
81
List four characteristics of mitochondria that help differentiate them from other organelles.
1. Reproduce by binary fission
2. Have two membranes
3. Have their own circular DNA
4. Have their own ribosomes
82
What is the primary function of chloroplasts?
Use light to make ATP and sugars
83
List four characteristics of chloroplasts that help distinguish them from other organelles.
1. Reproduce by binary fission
2. Have three membranes
3. Have their own circular DNA
4. Have their own ribosomes
84
List three major components of cell membranes.
1. Phospholipids
2. Proteins
3. Carbohydrates
85
What is the function of phospholipids in cell membranes?
They form the membrane's primary structure
86
Describe the basic structure of phospholipids.
They are amphipathic, with a polar hydrophilic head and two nonpolar hydrophobic tails
87
List the two major classes of proteins found in cell membranes.
1. Transmembrane
2. Peripheral
88
What are the functions of carbohydrates in the cell membrane?
1. Form an outer sugar coat
2. Help protect the cell
3. Help with cell identification
89
What are the six types of membrane protein functions?
1. Receptors
2. Cell identity
3. Enzymes
4. Cell adhesion
5. Cytoskeletal
6. Transport
90
What is the function of receptor proteins?
Detect signal molecules and initiate a response
91
What is the function of cell identity proteins?
Allow the cell to be recognized by other cells
92
What is the function of enzymes in the cell membrane?
Promote and catalyze chemical reactions
93
What is the function of cell adhesion proteins?
Allow the cell to attach to other cells
94
What is the function of cytoskeletal proteins?
Help the cytoskeleton to control cell shape
95
What is the function of transport proteins?
Move molecules across the membrane
96
____ occurs when molecules are moved down their concentration gradient.
Passive transport
97
____ transport does not require energy.
Passive
98
Facilitated diffusion is a form of....
Passive transport
99
____ occurs when molecules are moved up their concentration gradient.
Active transport
100
____ transport uses energy to create and maintain a concentration gradient.
Active
101
____ can create a pore in the cell membrane to allow molecules through.
Channel proteins
102
# True or false:
Channel proteins are always open.
False
Some are always open, but some open and close in response to a signal
103
____ proteins may or may not be specific to a certain molecule.
Channel
104
# True or false:
Channel proteins only engage in passive transport.
True
105
# True or false:
Carrier proteins only engage in active transport.
False
They can perform both passive and active transport.
106
During passive transport, carrier proteins carry out...
Facilitated diffusion
107
____ let molecules in the cell by binding to it, then reversing shape.
Carrier proteins
108
____ proteins are always specific to a certain molecule.
Carrier
109
During active transport, carrier proteins...
Pump molecules against their concentration gradient
110
Most carrier proteins that engage in active transport are...
ATPases
111
____ occurs when water moves down its concentration gradient to an area of higher solute concentration.
Osmosis
112
____ is the process by which eukaryotic cells ingest large materials.
Endocytosis
113
List the three main types of endocytosis.
1. Pinocytosis
2. Receptor-mediated endocytosis
3. Phagocytosis
114
____ is "cell drinking" and occurs when parts of the cell membrane bud inward to engulf all nearby molecules.
Pinocytosis
115
____ occurs when a cell recognizes and consumes specific macromolecules.
Receptor-mediated endocytosis
116
____ is "cell eating" and occurs when a cell engulfs another cell.
Phagocytosis
117
____ is the outward movement of proteins and lipids.
Exocytosis
118
____ occurs when an atom or molecule loses an electron.
Oxidation
119
____ occurs when an atom or molecule gains an electron.
Reduction
120
The ____ form of an atom or molecule has more energy.
Reduced
## Footnote
because it has more electrons than the oxidized form
121
What is the first law of thermodynamics?
Energy cannot be created or destroyed, it can only change forms.
122
What is the second law of thermodynamics?
The entropy of the universe is constantly increasing. Energy naturally changes forms from more ordered, less stable to less ordered, more stable.
123
____ regulate many reactions in cells.
Enzymes
124
# True or false:
Most enzymes are proteins.
True
125
Enzymes are usually specific to a...
Substrate
126
# True or false:
When acting as catalysts, enzymes are neither changed nor consumed in the reaction.
True
127
A substrate binds to an enzyme's...
Active site
128
How do enzymes catalyze reactions?
They lower the activation energy by applying stress
129
List four things that can affect the rates of enzyme-catalyzed reactions.
1. Concentration of the substrate
2. Concentration of the enzyme
3. Conditions that affect enzyme structure
4. Presence or absence or regulatory molecules
130
How does ATP store energy?
It stores energy in the covalent bonds in phosphates. Breaking the bonds releases energy.
131
# True or false:
ATP is a good option for long-term energy storage.
False
132
List the four stages of aerobic respiration of glucose.
1. Glycolysis
2. Pyruvate oxidation
3. Krebs cycle
4. ETC & chemiosmosis
133
Glycolysis occurs in the...
Cytosol
134
Pyruvate oxidation occurs in the...
Mitochondrial matrix
135
The Krebs cycle occurs in the...
Mitochondrial matrix
136
The ETC and chemiosmosis occur in the...
Inner mitochondrial membrane
137
List the main steps of glycolysis.
| (four)
1. Glucose is converted into 2 G3P.
2. Each G3P is converted into a 3-carbon molecule.
3. Each 3-carbon molecule is oxidized
4. An inorganic phosphate is added to each 3-carbon molecule.
138
For each molecule of glucose, glycolysis produces...
4 ATP (net 2)
2 NADH
2 pyruvate
139
List the main steps of pyruvate oxidation.
| (two)
1. CO2 is removed from pyruvate.
2. The remaining 2-carbon acetyl group attaches to a cofacor.
140
For each molecule of GLUCOSE, pyruvate oxidation produces...
2 CO2
2 NADH
2 acetyl-CoA
141
List the major steps of the Krebs cycle.
| (three)
1. acetyl-CoA is combined with oxaloacetate to make citrate.
2. Citrate is rearranged into 4-carbon succinate.
3. Succinate is used to make more oxaloacetate.
142
For each molecule of GLUCOSE, the Krebs cycle produces...
4 CO2
6 NADH
2 FADH2
2 ATP
143
List the major steps of the electron transport chain.
| (four)
1. 3 transmembrane proteins harvest energy from electrons
2. Energy from the electrons is used to make a proton gradient
3. Electrons are given to O2 to form H2O
4. The proton gradient produces ATP
144
What happens to the electrons from NADH in the ETC?
| (five)
1. They are given to an electron carrier.
2. They are given to the bc1 complex.
3. They are given to cytochrome C
4. They are given to the cytochrome oxidase complex
5. They are given to molecular oxygen.
145
For each molecule of glucose, the ETC produces...
28 ATP
6 H2O
146
During ____, protons are moved down their concentration gradient to release energy.
Chemiosmosis
147
____ uses the energy released by the proton gradient to make ATP.
ATP synthase
148
The energy from ____ proton(s) is enough to make one molecule of ATP.
Four
149
What is the total ATP yield for each step of aerobic respiration?
Glycolysis - 2 directly, 5 from NADH
Pyruvate oxidation - 5 from NADH
Krebs cycle - 2 directly, 15 from NADH, 3 from FADH2
150
For each glucose molecule, the cell produces...
32 ATP
(30 in eukaryotes)
151
Photosynthesis and aerobic respiration are effectively...
"Reverse reactions"
152
What is the equation for aerobic cellular respiration?
C6H12O6 + 6O2 = 6CO2 + 6H2O
(glucose + 6 oxygen = 6 carbon dioxide + 6 water)
153
What is the equation for photosynthesis?
6CO2 + 6H2O + light = C6H12O6 + 6O2
(6 carbon dioxide + 6 water + light = glucose + 6 oxygen)
154
____ are molecules that can absorb specific wavelengths of visible light.
Pigments
155
List the three main pigments found in photosynthetic cells.
1. Chlorophyll a
2. Chlorophyll b
3. Carotenoids
156
Which photosynthetic pigment(s) are capable of directly producing glucose from sunlight?
Chlorophyll a
157
Which colors of light does chlorophyll a absorb?
Red and violet-blue
158
Which colors of light does chlorophyll b absorb?
Blue and red-orange
159
Which colors of light do carotenoids absorb?
Blue and blue-green
160
Light-dependent reactions take place in the...
Thylakoids
161
The ____ reactions use energy from sunlight to make oxygen and ATP.
Light-dependent
162
The light-independent reactions take place in the...
Stroma
163
The ____ reactions use carbon fixation to make organic molecules from carbon dioxide.
Light-independent
164
During photosynthesis, electrons are taken from ____ to make NADPH.
Water
165
List the six places an electron from water travels during photosynthesis.
1. Photosystem 2
2. Plastiquinone (PQ)
3. b6f complex
4. Photosystem 1
5. Ferredoxin
6. NADP+
166
During photosynthesis, ATP is produced using...
A proton gradient across the thylakoid membrane
167
During photosynthesis, ATP is made by ATP synthase in the...
Chloroplasts
168
Each pair of electrons taken from water produces...
1 NADPH
~1 ATP
169
The ____ is a biochemical pathway that enables carbon fixation.
Calvin cycle
170
The Calvin cycle occurs in the....
Stroma
171
List the 3 phases of the Calvin cycle.
1. Carbon fixation
2. Reduction
3. Regeneration of RuBP
172
What happens during the carbon fixation phase of the Calvin cycle?
Carbon dioxide combines with RuBP to generate 2 molecules of PGA
173
Carbon fixation is catalyzed by...
Rubisco
174
What happens during the reduction phase of the Calvin cycle?
PGA is reduced to G3P. Some of the G3P then exits the cycle.
175
What happens during the regeneration phase of the Calvin cycle?
G3P is used to make more RuBP
176
How many turns of the Calvin cycle are required to produce one G3P?
Three
177
How many turns of the Calvin cycle are required to produce one glucose?
6
178
The 5' end of one strand of DNA is linked to the ____ end of the other strand.
3'
179
DNA has a double helix shape because...
The bonds between the bases twist it into that structure
180
In DNA, adenine forms hydrogen bonds with....
Thymine
181
Cytosine forms hydrogen bonds with...
Guanine
182
The sequence of the parent DNA strand determines...
The sequence of the daughter strand
183
# True or false:
Watson and Crick came up with their model of DNA without performing any experiments.
True
184
A DNA molecule is comprised of two nucleotide chains that twist together into a...
Double helix
185
The sugar-phosphate backbone of DNA is held together by....
Phosphodiester bonds
186
There are ____ hydrogen bond(s) between adenine and thymine.
Two
187
There are ____ hydrogen bond(s) between cytosine and guanine.
Three
188
The two grooves in the sugar-phosphate backbone are called the...
Major and minor grooves
189
The two strands of DNA are ____ to each other.
Antiparallel
190
List the three main functions of DNA polymerase.
1. Matches the template strand to complementary bases
2. Adds new bases to the daughter strand
3. Removes phosphates to grow the sugar-phosphate backbone
191
DNA polymerase synthesizes DNA in the ____ direction.
5' to 3'
192
The new base added by DNA polymerase must ____ the base on the parent strand.
Complement
193
The action of DNA polymerase in the 5'-3' direction is called...
Writing or synthesizing
194
The action of DNA polymerase in the 3'-5' direction is called...
Reading
195
DNA replication is....
Semi-discontinuous
196
The ____ strand of DNA is made continuously from an initial RNA primer.
Leading
197
The ____ strand of DNA is made discontinuously through multiple priming and synthesis events.
Lagging
198
List the four main steps involved in replicating the lagging strand.
1. RNA primase makes a short RNA primer
2. DNA polymerase 3 extends the primer into an Okazaki fragment
3. DNA polymerase 1 replaces the RNA primer with DNA
4. DNA ligase seals nicks in the sugar-phosphate backbone
199
List the three main components required for DNA replication.
1. Something to copy (template strand)
2. Something to do the copying (DNA polymerase)
3. Enough relevant building blocks (nucleoside triphosphates)
200
List the three main phases of DNA replication.
1. Initiation
2. Elongation
3. Termination
201
The genome encodes....
Functional molecules
202
List the five main types of RNA.
1. Messenger (mRNA)
2. Ribosomal (rRNA)
3. Transfer (tRNA)
4. Micro (miRNA)
5. Small nuclear (snRNA)
203
A ____ is a sequence of three nucleotides that usually specifies an amino acid.
Codon
204
There are a total of ____ possible codons.
64
205
____ codons specify an amino acid.
61
206
____ codons do not specify an amino acid and are "stop codons".
3
207
AUG, which codes for methionine, is often referred to as the...
"Start codon"
208
# True or false:
The genetic code is redundant.
True
209
# True or false:
The genetic code is practically universal.
True
210
____ is the process by which DNA is converted into RNA.
Transcription
211
Transcription occurs in the...
Nucleus
212
RNA polymerase is important in the process of....
Transcription
213
Transcription ends once a ____ is encountered and transcribed.
Terminator sequence
214
____ is the process by which mRNA is converted into a polypeptide sequence and ultimately a protein.
Translation
215
Translation occurs in the...
Ribosomes
216
mRNA, tRNA, and rRNA are all important in the process of....
Translation
217
Translation continues until a ____ is encountered.
Stop codon
218
List the three main phases of translation.
1. Initiation
2. Elongation
3. Termination
219
What happens during the initiation phase of translation?
| (four)
1. The small subunit binds to determine translation start site
2. Initiator tRNA binds to AUG at the P-site
3. The large subunit binds
4. The A-site and E-site are empty
220
The elongation phase of translation begins when...
The A-site is occupied for the first time
221
During the elongation phase of translation...
Amino acids are added to the polypeptide chain
222
What happens during the elongation phase of translation?
| (four)
1. An amino acid enters the A-site
2. A peptide bond forms between the amino acids at the A- and P-sites
3. The A-site amino acid moves to the P-site, and the P-site amino acid moves to the E-site
4. The tRNA at the E-site is released
223
The termination phase of translation begins when...
A stop codon enters the A-site
224
What happens during the termination phase of translation?
| (four)
1. A stop codon enters the A-site
2. The stop codon is recognized by a release factor
3. The release factor triggers the release of the completed polypeptide
4. The ribosome shifts one "codon" and disassembles
225
List the two main classes of DNA mutations.
1. Point mutations
2. Chromosome mutations
226
List the two main types of point mutations.
1. Base substitution
2. Frameshift
227
A base substitution occurs when...
One nucleotide base is changed
228
List the three types of base substitutions.
1. Silent mutation
2. Missense mutation
3. Nonsense mutation
229
A ____ mutation occurs when the nucleotide change does not change the encoded amino acid.
Silent
230
A ____ mutation occurs when the nucleotide change alters the encoded amino acid.
Missense
231
A ____ mutation occurs when the nucleotide change results in a stop codon and thus a nonfunctional protein.
Nonsense
232
A ____ mutation occurs when a nucleotide base is added or deleted, thus changing the downstream reading frame.
Frameshift
233
List the four main types of chromosome mutations.
1. Deletion
2. Duplication
3. Inversion
4. Translocation
234
____ occurs when part of a chromsome is lost.
Deletion
235
____ occurs when part of a chromosome is copied.
Duplication
236
____ occurs when part of a chromosome is in reverse order.
Inversion
237
____ occurs when part of a chromosome moves onto another chromosome.
Translocation
238
List the three main types of gene expression control.
1. Transcriptional
2. Post-transcriptional
3. Post-translational
239
____ regulation is the most common form of gene expression regulation.
Transcriptional
240
Which type of gene expression control only occurs in eukaryotes?
Post-transcriptional
241
____ is a form of transcriptional regulation that occurs when proteins promote or inhibit transcription.
Positive or negative control
242
____ occurs when activator proteins recruit RNA polymerase to help transcription begin.
Positive control
243
____ occurs when repressor proteins prevent a gene from being transcribed.
Negative control
244
Regulatory proteins are also called...
Transcription factors
245
____ are forms of transcriptional regulation that occur when molecules in the environment stimulate or inhibit transcription.
Induction and repression
246
____ regulation occurs during mRNA processing, transport, and/or translation.
Post-transcriptional
247
List four main types of post-transcriptional regulation.
1. Alternative splicing
2. Export inhibition
3. Translation inhibition
4. Regulation by small RNAs
248
____ is the process by which a single primary transcript can code for multiple proteins depending on how the introns are cut out.
Alternative splicing
249
____ is a form of post-transcriptional regulation where mRNAs are prevented from exiting the nucleus.
Export inhibition
250
____ occurs when a cell uses proteins to prevent mRNA in the cytoplasm from being translated.
Translation inhibition
251
What happens during post-transcriptional regulation by small RNAs?
| (three)
1. The small RNAs form a RISC complex with proteins
2. The small RNAs bind to the target mRNA
3. The proteins in RISC block translation or degrade the mRNA
252
DNA is packaged into discrete molecules called...
Chromosomes
253
Eukaryotic chromosomes are....
Linear
254
# True or false:
Eukaryotic chromosomes are several molecules of DNA packaged together.
False
They are a single continuous molecule of DNA
255
Eukaryotic chromosomes are made of a substance called...
Chromatin
256
List and differentiate the two types of chromatin.
1. Heterochromatin - tightly packaged and cannot be expressed
2. Euchromatin - loosely package and is able to be expressed
257
Explain the 3 levels of DNA packaging in eukaryotes.
1. DNA condenses around histone proteins, which attach to each other to make a nucleosome fiber
2. The fiber condenses into a solenoid
3. Several solenoids condense into a mitotic chromosome
258
List and define the four phases of the eukaryotic cell cycle.
1. G1 - primary growth phase
2. S - DNA replication
3. G2 - more growth and preparation
4. M - mitosis, nuclear and cytoplasmic division
259
What happens during interphase?
The cell grows, replicates its DNA, and carries out its normal functions
260
List the six phases of mitosis.
1. Prophase
2. Prometaphase
3. Metaphase
4. Anaphase
5. Telophase
6. Cytokinesis
261
What happens during prophase?
1. The mitotic spindle assembles
2. The chromosomes condense
3. The nuclear envelope disassembles
262
What happens during prometaphase?
1. The chromosomes are released into the cytoplasm
2. The chromosomes attach to the mitotic spindle
3. The chromsomes begin to move towards the spindle equator
263
What happens during metaphase?
1. The chromosomes align on the metaphase plate (spindle equator)
264
What happens during anaphase?
1. The sister chromatids separate
2. The chromatids move towards opposite poles of the spindle
3. Microtubules in the spindle shorten
265
What happens during telophase?
1. The chromosomes de-condense
2. The nuclear envelope re-forms
266
What happens during cytokinesis?
A cleavage furrow or cell plate forms, splitting the cytoplasm into two daughter cells.
267
List the three major cell cycle checkpoints.
1. G1/S
2. G2/M
3. Spindle
268
What occurs at the G1/S checkpoint?
The cell decides whether to commit to S phase
Factors: cell size, presence of nutrients, presence of growth factors
269
What occurs at the G2/M checkpoint?
The cell decides whether to commit to M phase
Factors: whether DNA replication is complete, extent of DNA damage
270
What occurs at the spindle checkpoint?
The cell decides whether to commit to anaphase
Factors: whether the chromosomes are aligned on the metaphase plate
271
Why is meiosis important in sexual reproduction?
Diploid germline cells undergo meiosis to produce genetically unique haploid gametes
272
List three important events in meiosis.
1. Synapsis
2. Crossing over
3. Reduction division
273
Synapsis occurs during...
Early prophase 1
274
During synapsis...
Homologous chromosomes become closely associated
275
Crossing over begins after synapsis, and continues until...
Anaphase 1
276
During crossing over events...
Genetic material is exchanged between non-sister chromatids, enabling genetic recombination
277
Reduction division occurs during...
Meiosis 1
278
Reduction division is the process by which...
A diploid parent cell produces haploid daughter cells
279
What happens to the chromosomes during prophase 1?
| (three)
1. Homologues associate with each other
2. Crossing over events occur
3. Each homologue attaches to an opposite spindle pole
280
What happens to the chromosomes during metaphase 1?
The homologues congress to the metaphase plate
281
What happens to the chromosomes during anaphase 1?
| (three)
1. Crossing over events stop
2. The homologues are separated
3. The sister chromatids remain attached
282
What happens to the chromosomes during meiosis 2?
The sister chromatids are separated
283
What is observed during a monohybrid cross?
| (parent, F1, F2, F3)
Parent - both are homozygous for a trait
F1 - 100% are heterozygous and express the dominant trait
F2 - 75% express the dominant trait and 25% express the recessive trait
F3 - 1:2:1 genotype ratio, 3:1 phenotype ratio
284
What is observed during a dihybrid cross?
| (parent, F1, F2)
Parent - both homozygous for 2 traits
F1: 100% heterozygous dominant for both traits
F2: 9:3:3:1 phenotype ratio
285
Mendel's Principle of Independent Assortment states that...
In a dihybrid cross, alleles assort independently.
(the segregation of allele pairs is independent)
286
List the six non-Mendelian inheritance patterns.
1. Multiple alleles
2. Polygenic inheritance
3. Pleiotropy
4. Incomplete dominance
5. Codominance
6. Epistasis
287
____ occurs when there are more than 2 alleles for a gene present in a population.
Multiple alleles
(ex: human ABO blood typing)
288
____ occurs when a single trait is controlled by multiple genes, as well as environmental factors.
Polygenic inheritance
(ex: human height, obesity)
289
____ occurs when a single gene impacts multiple traits, making the effects of a mutation difficult to predict.
Pleiotropy
(ex: cystic fibrosis)
290
____ occurs when the heterozygous phenotype is an intermediate of the homozygous phenotypes.
Incomplete dominance
(ex: pink snapdragons)
291
____ occurs when a heterozygote has aspects of both homozygous phenotypes.
Codominance
(ex: AB blood type)
292
____ occurs when the products of genes interact, and/or the genes show some form of dependence at the level of function.
Epistasis
(ex: labrador retriever coat colors)
293
# True or false:
The way that sex is determined varies between species.
True
294
# True or false:
The structure, number, and naming of sex chromosomes is similar among most species.
False
295
In humans, sex is determined by...
The presence or absence of the Y chromosome (specifically, the SRY gene it carries)
296
Humans have ____ pair(s) of autosomes.
22
297
Humans have ____ pair(s) of sex chromosomes.
1
298
Traits caused by genes located on the X chromosome are called...
X-linked or sex-linked
299
For sex-linked traits, the male phenotype is determined by...
The X chromosome he received from his mother
300
# True or false:
A man who expresses a sex-linked trait could pass the trait on to his sons.
False
301
In order to express most sex-linked traits, females must....
Have two copies of the mutated gene
302
# True or false:
A man who is affected by a sex-linked trait and a woman who is a carrier for that trait could have affected daughters.
True
303
Many human genetic disorders are the result of...
Mutations or nondisjunction
304
____ occurs when chromosomes fail to align properly on the metaphase plate and thus do not segregate correctly.
Nondisjunction
305
Nondisjunction leads to...
Aneuploidy
306
# True or false:
In humans, aneuploidy is almost always fatal before or shortly after birth.
True
307
Down Syndrome (Trisomy 21) is a result of....
Autosome nondisjunction
308
# True or false:
The consequences of nondisjunction in sex chromosomes is usually less severe than in autosomes.
True
309
A common effect of sex chromosome nondisjunction is...
Mental disability and sterility
