Exam 3 Flashcards
1
Q
In which stage of the cell cycle are sister chromatids separated and pulled to the opposite poles of the cell?
A
Anaphase
2
Q
What relieves mechanical strain that builds up (twisting forces) during replication in E. coli?
A
topoisomerase
3
Q
Strand initiation in DNA replication is accomplished when an enzyme lays down a primer. Of what molecule is that primer composed?
A
RNA
4
Q
A group of cells is assayed for DNA content immediately following mitosis and are found to have an average of 8 picograms of DNA per nucleus. Those cells would have _____ picograms of DNA at the end of the S phase and _____ picograms of DNA at the end of G2.
A
16, 16
5
Q
Why is DNA replication called semiconservative?
A
Each daughter duplex contains one strand from the parent structure.
6
Q
In human and many other eukaryotic species’ cells, the nuclear membrane has to disappear to permit
A
the attachment of microtubules to kinetochores
7
Q
The specific site on the bacterial chromosome at which replication begins is called the ________
A
origin
8
Q
Replication moves outward from the origin in ________ direction(s) and is said to be ________
A
both, bidirectional
9
Q
What proteins bind selectively to single-stranded DNA and are responsible for keeping it extended and preventing it from being rewound and becoming double stranded?
A
single-stranded DNA binding (SSB) proteins
10
Q
What type of hypothesized replication (Meselson-Stahl model) results in one duplex containing both parental strands and the other duplex containing two new strands of DNA after the two parental strands had served as templates for the two daughter strands?
A
conservative replication
11
Q
In which direction are nucleotides laid down in the new strand while DNA is being synthesized?
A
5’—>3‘
12
Q
The RNA primers that initiate replication are subsequently _____ and the resulting gap in the strand is _______ DNA and then sealed by _______
A
removed, filled in with, DNA ligase
13
Q
In which direction do the DNA strands grow during replication?
A
one toward the replication fork and one away from the replication fork
14
Q
New strand initiation during replication is carried out by an enzyme that makes a short RNA molecule that is used as a primer; the enzyme is a distinct type of RNA polymerase, called _______
A
Primase
15
Q
Cells that are in a non-dividing state are in which phase?
A
G0
16
Q
What are two copies of the same DNA (have the same exact sequence)?
A
Sister Chromatids
17
Q
What are two copies of the same genes, but not always the same sequence (one from mom, one from dad)?
A
Homologous Chromosomes
18
Q
In which stage of the cell cycle are sister chromatids separated and pulled to the opposite poles of the cell?
A
Anaphase
19
Q
Meiosis is the separation of:
A
Both Sister Chromatids and Homologous Chromosomes
20
Q
During replication, DNA is constructed in small segments called ________ that are rapidly linked to longer pieces of DNA synthesized earlier.
A
Okazaki fragments
21
Q
A group of cells is assayed for DNA content immediately following mitosis and are found to have an average of 8 picograms of DNA per nucleus. Those cells would have _____ picograms of DNA at the end of the S phase and _____ picograms of DNA at the end of G2.
A
16, 16
22
Q
The enzyme that joins the small fragments of the lagging strand together into a continuous strand is called
A
DNA ligase
23
Q
Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called:
A
Cyclins
24
Q
If a liver cell of an animal has 24 chromosomes total, the sperm cells from this animal will have how many chromosomes?
A
12
25
DNA is undamaged, therefore DNA will be allowed to replicate.
G1
26
Chromosomes have replicated correctly and MPF is present.
G2
27
Spindle fibers are properly attached to sister chromatids at the kinetochore
M
28
Where does Glycolosis take place in eukaryotic cells?
Cytoplasm (Cytosol)
29
What types of molecules are the major structural components of the cell membrane?
Phospholipids and Proteins
30
Which eukaryotic organelle or organelles resemble prokaryotic cells?
Mitochondria
| Chloroplasts
31
A series of enzymes catalyze the reaction X to Y to Z. Product A binds to the enzyme that converts X to Y at a position remote from its activation site. The binding decreases the activity of the enzyme. What is substance A?
An allosteric inhibitor
32
What occurs in meiosis but not in mitosis?
synapsis of chromosomes
33
What is a major difference between mitosis and meiosis I in a diploid organism?
Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in meiosis I
34
Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must ________.
be removed before sister chromatids can separate
35
Sister chromatids separate from each other during ________.
mitosis and meiosis II
36
Why might adding inorganic phosphorus to a reaction mixture where glycolysis is rapidly proceeding help sustain the metabolic pathway?
The metabolic intermediates of glycolysis are phosphorylated.
37
In humans, xeroderma pigmentosum (XP) is a disorder of the nucleotide excision repair mechanism. These individuals are unable to repair DNA damage caused by ultraviolet light. Which of the following are the most prominent types of DNA lesions in individuals suffering from xeroderma pigmentosum?
thymine dimers
38
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together.
39
Researchers found E. coli that had mutation rates 100 times higher than normal. Which of the following is the most likely cause of these results?
The proofreading mechanism of DNA polymerase was not working properly.
40
Which of the following reactions is the correct description of the beginning of the Citric Acid (Kreb’s) Cycle?
Acetyl CoA + oxaloacetate -> citrate
41
What are the products of glycolysis?
2 pyruvate
2 (net) ATP
2 NADH
42
The product of the p53 gene ________.
inhibits the cell cycle
43
What does NOT occur during mitosis?
replication of the DNA
44
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does NOT happen, cells would most likely be arrested in ________.
metaphase
45
FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to ________.
the cleavage furrow of eukaryotic animal cells
46
Cyclin-dependent kinase (Cdk) is ________.
an enzyme that attaches phosphate groups to other proteins
47
You are observing diseased cells in a medical laboratory. Upon close inspection, you notice that the cells contain many food vacuoles, yet the cells are dying of starvation. Which organelle is most likely to be the one malfunctioning within these cells?
Lysosomes
48
Where are the proteins of the electron transport chain located?
Mitochondrial inner membrane
49
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is ________.
oxygen
50
What type of bonds form between the monomers that make up carbohydrates?
Glycosidic
51
Carbon skeletons to be broken down during cellular respiration can be obtained from:
Polysaccharides, Lipids, and Proteins
52
What is diffusion?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
53
Enzymes increase the speed of certain biological chemical reactions by
bringing reactants into physical contact with one another
54
What type of bonds hold the nucleotides together to make up the backbone of DNA?
Covalent
55
Muscle cells in oxygen deprivation convert pyruvate to ______ and in this step gain ______.
Lactic acid, NAD+
56
For a cell to function at an optimum, the ideal ratio between surface area and volume is?
Low volume and high surface area
57
Which of the following would you expect of a eukaryote lacking telomerase?
a reduction in chromosome length in gametes
58
Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of what?
gaps left at the 5' end of the lagging strand
59
Under some conditions, too much pyruvate is produced and it is more energy favorable for the cell to slow down glycolysis. What would be most likely to act as a feedback inhibitor for the process of glycolysis?
**
60
What is a major difference between meiosis II and mitosis in a diploid animal?
Meiosis II occurs in a haploid cell, and mitosis occurs in diploid cells.
61
What is a major difference between mitosis and meiosis I in a diploid organism?
Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in meiosis I.
62
Which of the following occurs in meiosis but not in mitosis?
synapsis of chromosomes
63
Homologous chromosomes ________.
carry information for the same traits
64
Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must ________.
be removed before sister chromatids can separate
65
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to ________.
disruption of mitotic spindle formation
66
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does NOT happen, cells would most likely be arrested in ________.
metaphase
67
If a cell has accumulated DNA damage, it is unlikely to ________.
pass the G2 checkpoint
68
How is plant cell cytokinesis different from animal cell cytokinesis?
Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
69
What sequence correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
70
n photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during ________.
photosynthesis and respiration
71
What statement best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules.
72
Codes for a protein.
mRNA
73
Is a carrier for amino acids and has an anticodon
tRNA
74
Along with proteins, makes up a ribosome.
rRNA
75
This occurs when a cell divides to form two nuclei that are genetically identical.
is true for mitosis only
76
Homologous chromosomes synapse and crossing over occurs
is true for meiosis I only
77
Centromeres uncouple and chromatids are separated from each other.
is true for mitosis and meiosis II
78
Independent assortment of chromosomes occurs.
is true during Metaphase and Anaphase for meiosis only
79
Due to the use of RNA primers in DNA synthesis, the lagging strand of DNA requires extra attention to be sure
telomeres do not shorten with each DNA replication
80
Breaks hydrogen bonds between DNA nucleotides to separate the two strands of DNA.
Helicase
81
Adheres to DNA to keep complementary base pairs from re-annealing with one another
Single-Stranded Binding Proteins
82
Breaks covalent bonds between nucleotides to relieve the stress of strands twisting.
Topoisomerase
83
E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
one low-density and one intermediate-density band
84
Semiconservative replication involves a template. What is the template?
one strand of the DNA molecule
85
Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
86
Shell color in clams is thought to be controlled by three different genes (each with two alleles). Shell coloration runs a range between pure white and dark purple. The addition of dominant alleles makes the shells more purple in coloration, while the addition of recessive alleles makes the shells more white. The majority of clams have shells that are medium purple, whereas the other colors are present, but in fewer numbers. This is an example of:
Quantitative traits
87
As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy?
It is used to establish and maintain a proton gradient.
88
In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and ___
carotenoids and other pigments are still present in the leaves
89
Plants photosynthesize _____
only in the light but respire in light and dark
90
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following?
incomplete dominance
91
The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?
All of the genes controlling the traits behaved as if they were on different chromosomes.
92
In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
tortoiseshell females; black males
93
In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0
94
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their twenties. How likely is it for a woman to have this condition?
One-half of the daughters of an affected father and a carrier mother could have this condition.
95
The combination of alleles that an organism inherits.
Genotype
96
The outward appearance of an organism based on inherited DNA sequence.
Phenotype
97
A particular eukaryotic protein is 300 amino acids long. Which of the following could be the maximum number of nucleotides in the DNA that codes for the amino acids in this protein?
900
98
RNA is created in a ________ fashion, which means DNA is read from _
5’ to 3’ / 3’ to 5’
99
The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others.
In electron micrographs of HSV infection, it can be seen that the intact virus initially reacts with cell surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations?
The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus.
100
What characteristics, structures, or processes is common to bacteria and viruses?
genetic material composed of nucleic acid
101
A sexually reproducing organism has two genes located on different chromosomes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following are possible allele combinations in this organism’s gametes?
hT
| HT
102
When a bacteriophage infects a bacterial cell, the phage’s protein coat
remains outside of the cell
103
Codons are sets of three _____ that encode a protein.
RNA nucleotides
104
In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and ________ of the last nucleotide in the polymer.
the 3' OH
105
Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine and cytosine forms hydrogen bonds with guanine. This arrangement ________.
permits complementary base pairing
106
In an analysis of the nucleotide composition of DNA, which of the following will be found?
A + C = G + T
107
Plants photosynthesize ________.
only in the light but respire in light and dark
108
Chlorophylls absorb most light in which colors of the visible range?
blue and red
109
Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
110
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
111
In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during ________.
photosynthesis and respiration
112
What is mitosis?
the division of somatic cells (not sex cells)
113
From what process are the daughter cells exact copies of the parent?
mitosis
114
What are the goals of mitosis?
organismal growth, development, repair
115
what is the simplest DNA packaging?
double stranded helical structure
116
How are nucleosomes formed?
when DNA wraps around histones
117
How are chromosomes formed?
nucleosomes fold and fibers tightly coil
118
What is the difference between sister chromatids and homologous chromosomes?
sister chromatids have the same DNA, while homologous chromosomes have different sequences where one comes from the mother and the one comes from the father
119
A akin cell has 23 pairs of chromosomes. This cell undergoes mitosis. How many chromosomes does this cell have?
46
120
What is interphase?
everything before mitosis
121
What would happen if the cell was not completely grown and not ready for the chromosomes to be replicated?
the cell would arrest in the G0 phase
122
In what phase does DNA replicate?
S phase
123
What happens in prophase of mitosis?
chromosomes condense creating a centromere with two sister chromatids attached and mitotic spindles begin to move
124
What happens in pro metaphase of mitosis?
nuclear envelope starts to break down and kinetochores are formed on the centrioles ready for the microtubules to attach
125
What happens in metaphase of mitosis?
attached chromosomes line up at the center plane of the cell (the metaphase plate)
126
What happens in anaphase of mitosis?
sister chromatids detach at the centromere and are pulled to either pole of the cell by spindle fibers
127
What happens in telophase of mitosis?
new nuclear membranes begin to form
128
What happens in cytokinesis in mitosis?
division of cytoplasm; microfilaments of the cytoskeleton begin to create the cleavage furrow
129
What separates during mitosis?
sister chromatids
130
Serve as the organizing center of the microtubules
centrosomes
131
are on either side of the chromosome where the microtubules attach
kinetochores
132
How do microtubules shorten?
they shorten one end at the kinetochore
133
What aids in spindle fiber shortening?
motor proteins
134
What shortens at he plus end?
microtubules
135
What travel to the minus end?
motor proteins
136
How does a cleavage furrow occur?
microfilaments in the cytoskeleton work to bring the cytoplasm inward
137
How does a cell plate form?
vesicles fuse together
138
How does cytokinesis begin in plants?
a cell plate begins to separate the cytoplasm
139
How does cytokinesis begin in an animal cell?
a cleavage furrow forms
140
what is binary fission?
how bacteria replicate
141
How do bacteria separate?
FtsZ proteins form a ring around the midpoint, the ring directs the formation of a septum and the cell separates
142
What type of replication leads to cells that are identical to the parents cells after duplication?
Binary fission
| Mitosis
143
How does the G2 checkpoint work?
- cyclin builds up as it approaches the G2 phase
- as it accumulates it binds to CDK which is already in the cell
- MPF phosphorylates proteins needed for mitosis
- the combination of cyclin and CDK tell the cell to go on to the next phase
144
What would happen if all the kinetochores were not attached?
MAD would stay attached to the CDC20
145
What would happen if APC and CDC20 never bind?
mitosis would not continue because Securin would never get ubiquitinated
146
What does ubiquitin do?
softens (degrades( securing for separate to get through securin
147
What will happen when any damage does not get detected by the checkpoints?
The damaged cells will continue to divide and create cancerous cells
148
Define benign
cells will not spread because they re not cancerous
149
Define malignant
cells will replicate rapidly and begin to metastasize to other areas of the body
150
In which process does the synapsis of homologous chromosomes occur?
meiosis
151
In which phase is DNA replicated for Mitosis/Meiosis?
S phase
152
How many daughter cells will be produced at the end of Meiosis I?
2
153
What is the name of the structure that is formed from the joining of homologous chromosomes?
tetrad
154
Which phase of Meiosis does crossing over occur?
Prophase I
155
What is the ploidy of the daughter cells after Telophase I/Cytokinesis?
n
156
Separation of homologous occurs in
anaphase I
157
What is the policy of the daughter cells formed by Meiosis II?
n
158
In which phase of Meiosis would you expect independent assortment to occur?
Metaphase I
159
What of the following is NOT an advantage of using pea plants as model system for inheritance?
Pea planta always reproduce through self-pollination
160
refers to genetic material that determines a certain trait
gene
161
is one of the alternative forms of the gene that displays a certain trait
allele
162
Dominance is not
directly related to the fitness of an organism
163
What are the possible gametes that could result from a heterozygous individual with the allele combination Rr?
R and r
164
Which of the following inheritance patterns requires more than one gene to obtain a phenotype?
Quantitative Traits
165
Hemophilia in humans is due to an X-chromosome mutation. What will be the results of mating between a normal (non-carrier) female and a hemophiliac male?
All sins are normal and all daughters are carriers
166
Genes can code for
Proteins, mRNA, tRNA, rRNA
167
What is the best sequence of the central dogma of biology?
DNA -> transcription -> RNA -> translation -> protein
168
Given the following RNA strand, predict the template strand of the DNA.
5'--AUGCGCACGCCCGAUUAG--3'
3'--UACGCGUGCGGGCUAAUC--5'
169
What are the features of the genetic code?
- it is nearly universal
- it is conservative
- it is unambiguous
- it is redundant
170
how is the genetic code redundant ?
amino acids can be coded by multiple codons
171
how is the genetic code unambiguous?
one codon equates to only one amino acid
172
how is the genetic code universal?
same codons code for same amino acids in all organisms
173
how is the genetic code conservative?
when multiple codons code for the same amino acid, first two bases are usually the same (wobble)
174
Do all mutations cause a change in the amino acid sequence?
no
175
Similar to RNA, _____
chromosomes can also be mutated
176
What reaction is the correct description of the beginning of the Citric Acid (Kreb’s) Cycle?
Acetyl CoA + oxaloacetate -> citrate
177
The enzyme that joins the small fragments of the lagging strand together into a continuous strand is called _______.
DNA ligase
178
An individual has the genotype of rrYy for two Mendelian genes. What are all of the following that are possible gametes from this individual?
rY
| ry
179
The function of RNA is
to hold the code required for the creation of a protein and to have the ability to migrate out of the nucleus of a cell into the cytoplasm
180
The type of bond that links two nucleotides along a single strand of RNA is known as a _________ bond.
Phosphodiester
181
Fur thickness in dogs is inherited via three different genes (each with two possible alleles). The addition of dominant alleles makes the fur more thick. The addition of recessive alleles makes the fur thinner. The majority of dogs have a median fur thickness. What inheritance pattern best describes the above scenario?
Quantitative Trait
182
Which phase of mitosis is associated with separation of chromatids?
anaphase
183
Where does Glycolosis take place in eukaryotic cells?
Cytoplasm (Cytosol)
184
How might a scientific theory be modified?
by the uncovering of new information using the scientific method
185
In an experiment, the thylakoids are removed from the chloroplasts of a plant cell and kept in a culture medium. The culture is exposed to sunlight, CO2, and water, but no sugars are formed. What is the most likely explanation for this result?
The area within a plant cell where sugar is created is no longer present.
186
If this cell also contains defective Securin that cannot be broken down___
the cell will stall in metaphase
187
If this cell also contains defective APC that will not bind CDC20,
the cell will not divide
188
If this cell also contains defective Separase that cannot chew cohesion,
the cell will not divide
189
Areas between two animal cells where integral proteins line up and allow chemical signals to flow from one cell to another
Gap junctions
190
A break in the cell wall between two plant cells where chemical messages can flow from one cell to another.
Plasmodesmata
191
Areas between two animal cells where proteins align and allow for anchorage of one cell to another
Tight Junctions
192
In which specific stage of the cell cycle does DNA replication occur?
S phase
193
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following?
incomplete dominance
194
The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?
All of the genes controlling the traits behaved as if they were on different chromosomes.
195
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white.
(a) What is the most probable genotype of each parent?
(b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.)
Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1
196
In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
roan × roan
197
What are the similarities between mitosis and meiosis?
DNA replication occurs once before cell division begins.
Process begins with a single, diploid cell.
Separation of sister chromatids.
198
When does DNA replication take place in meiosis? DNA replication ________.
occurs before meiosis I begins
199
What occurs in meiosis but not in mitosis?
synapsis of chromosomes
200
Sister chromatids separate from each other during ________.
mitosis and meiosis II
201
Independent assortment of chromosomes occurs during ________.
meiosis I only
202
What type of division will start with a diploid eukaryotic cell and end with two diploid eukaryotic cells?
Mitosis
203
Replication moves outward from the origin in ________ direction(s) and is said to be ________.
both, bidirectional
204
What statement best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, P, and NADP+ to the light reactions.
205
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to ________.
disruption of mitotic spindle formation
206
Kinetochore microtubules assist in the process of splitting centromeres by ________.
creating tension by pulling toward opposite poles
207
Cyclin-dependent kinase (Cdk) is ________.
an enzyme that attaches phosphate groups to other proteins
208
In a Mendelian dihybrid cross, two true-breeding plants differing in seed color and seed shape are crossed. Yellow seeds (Y) are dominant over green seeds (y) and round seeds (R) are dominant over wrinkled (r).
What ratio of plants in the F2 generation would be expected to produce green, round seeds?
3/16
209
A cell, after undergoing glycolysis, takes the products from these reactions and immediately begins alcoholic fermentation. Which of the following cell types could achieve the above scenario?
A prokaryotic cell
| A yeast cell
210
The DNA strand growing toward the replication fork grows ______ in a 5'—>3' direction as the replication fork advances and is called the ________.
continuously, leading strand
211
In pea plants, two Mendelian genes control flower color and plant height. For flower color, purple is dominant to white. For plant height, tall is dominant to short. You are interested in determining the genotype of a random purple, tall plant from your stock. To do so, you should perform a test cross with a plant with which of the following genotypes?
White and short
212
What are the final products (or “outputs”) of the light-independent reactions of photosynthesis?
ADP + P
NADP+
O2
Sugar
213
What polysaccharide has the main function of being a structural component of bacterial cell walls?
Peptidoglycan
214
If a somatic cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?
32
215
Why might a point mutation in DNA make a difference in the level of a protein's activity?
It might substitute a different amino acid in the active site.
216
The mutation resulting in sickle cell disease changes one base pair of DNA so that a codon now codes for a different amino acid, making it an example of a ________.
missense mutation
217
What are the final products (or “outputs”) of glycolysis?
NADH
Pyruvate
ATP
218
A cell, after undergoing glycolysis, takes the products from these reactions and immediately shuttles them to the mitochondria for processing. Which of the following cell types could achieve the above scenario?
A plant cell
| A human muscle cell
219
In human and many other eukaryotic species' cells, the nuclear membrane has to disappear to permit
the attachment of microtubules to kinetochores
220
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to ________.
disruption of mitotic spindle formation
221
How is plant cell cytokinesis different from animal cell cytokinesis?
Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
222
The product of the p53 gene ________.
inhibits the cell cycle
223
Kinetochore microtubules assist in the process of splitting centromeres by ________.
creating tension by pulling toward opposite poles
224
In an experiment, the thylakoids are removed from the chloroplasts of a plant cell and kept in a culture medium. The culture is exposed to sunlight, CO2, and water, but no sugars are formed. What is the most likely explanation for this result?
The area within a plant cell where sugar is created is no longer present.
225
A plant cell has been able to make in a sugar molecule as a food source, but it is still dying of starvation. Which organelle’s malfunction would be responsible for this result?
Central Vacuole
226
Which polysaccharide has the main function of being a structural component of bacterial cell walls?
Peptidoglycan
227
Where does Glycolosis take place in eukaryotic cells?
Cytoplasm (Cytosol)
228
In which specific stage of the cell cycle does DNA replication occur?
S
229
What does it mean when we say the genetic code is redundant?
More than one codon can specify the addition of the same amino acid
230
Why might a point mutation in DNA make a difference in the level of a protein's activity?
It might substitute a different amino acid in the active site.
231
A mutation that results in premature termination of translation ________.
is a nonsense mutation
232
In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?
0
233
What type of division will start with a diploid eukaryotic cell and end with 4 haploid eukaryotic cells?
Meiosis
234
What are the final products (or “outputs”) of the light-independent reactions of photosynthesis?
Sugar
ADP + P
NADP+
235
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, P, and NADP+ to the light reactions.
236
Two molecules are bonded together due to the attraction of their opposite, yet partial charges.
What type of bond is described above?
Hydrogen
237
Bacteria are grown in a medium containing 15NH4Cl for a number of generations so that all of the DNA is made of fully "heavy" DNA. The bacteria are moved to a new medium and grown in 14NH4Cl so that all new DNA will be "light". If replication were dispersive, what would the DNA look like after one generation time.
Each strand is made of a mixture of "heavy" and "light" DNA with each strand being about 50% "light".
238
If a somatic cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?
32
239
Homologous chromosomes ________.
carry information for the same traits
240
What is a major difference between meiosis II and mitosis in a diploid animal?
Meiosis II occurs in a haploid cell, and mitosis occurs in diploid cells.
241
What makes sexually reproduced offspring genetically different from their parents?
genetic recombination during meiosis
242
Sexual reproduction ________.
can produce diverse phenotypes that may enhance survival of a population in a changing environment
243
Turner syndrome is characterized by the presence of only one X chromosome in an affected female. Which of the following accurately describes Turner syndrome?
monosomy
244
Sister chromatids separate from each other during ________.
mitosis and meiosis II
245
Which phase of mitosis is associated with separation of chromatids?
anaphase
