Deck 10: How Cells Divide

Question 1

You are assembling a model of a chromosome, but begin having some trouble when you get to the step of forming chromatin loops.If you are unable to resolve this problem, what step of chromosome structure would you be unable to achieve?

A)Histone/DNA complex
B)Nucleosome
C)Solenoid
D)Rosettes

Answer 1

D

Question 2

The accommodation of the very long DNA strands that are part of a chromosome into the limited space of the nucleus is achieved by coiling the DNA around beads of histones into repeating subunits.These DNA-wrapped histones are called:

A)Solenoids
B)Nucleosomes
C)Chromatin loops
D)Rosettes Review Figure 10.5

Answer 2

B

Question 3

If there are 32 sister chromatids in a normal somatic cell, what is the haploid number for that cell?

A)8
B)16
C)32
D)64

Answer 3

A

Question 4

A cell biologist produces a karyotype of mouse somatic cells arrested in mitosis.She sees 40 chromosomes, which is completely normal for mice.Based on this information, what is the haploid number of chromosomes for mice?

A)10
B)20
C)40
D)80

Question 5

A somatic cell from a garden pea normally contains 14 chromosomes.How many sister chromatids would that cell contain during G1 of the cell cycle?

A)0
B)7
C)14
D)28

Question 6

In later chapters, you will learn more about the regulation of gene expression.One way to regulate gene expression is to make changes to the histone proteins to alter how tightly the DNA is coiled and wrapped.The more tightly coiled and wrapped a particular region of DNA is, the less likely it is that the genes in that region will be expressed.Bearing this in mind, how tightly do you think regions of heterochromatin are compacted?

A)Very tightly
B)Moderately
C)Loosely
D)Not at all

Question 7

How does the organization of the bacterial genome differ from the organization of the eukaryotic genome?

A)The compaction of the eukaryotic genome involves structural maintenance of chromosome (SMC) proteins, and the compaction of the bacterial genome does not.
B)Most bacterial chromosomes are circular and the eukaryotic chromosomes contained in the nucleus are not.
C)Bacterial chromosomes are made up of RNA and eukaryotic chromosomes are made up of DNA.
D)The eukaryotic genome is found on chromosomes and there are no chromosomes in bacterial cells.

Question 8

The number of chromosomes in diploid eukaryotic cellsrev: 10_20_2014_QC_57039

A)is 46.
B)can be predicted by the size of the organism.
C)changes as each organism grows and ages.
D)varies considerably from 2 to over 1000 in different species.

Question 9

If there are 32 sister chromatids in a normal somatic cell, how many chromosomes are there?

A)8
B)16
C)32
D)64

Question 10

The point of constriction on chromosomes that contains certain repeated DNA sequences that bind specific proteins is called:

A)The kinetochore
B)The centromere
C)The cohesin complex
D)The centriole

Question 11

These structures are held together by cohesin:

A)Nucleosomes
B)Sister chromatids
C)Homologous chromosomes
D)Solenoids

Question 12

If a cell contained a mutation in the gene that encodes FtsZ, which process would be affected?

A)Septation
B)Cytokinesis
C)Prophase
D)DNA Synthesis

Question 13

A somatic cell from a corn plant normally contains 20 chromosomes.How many sister chromatids would that cell contain during G2 of the cell cycle?

A)0
B)10
C)20
D)40

Question 14

The division of a bacterial cell occurs as the:

A)cell wall develops cracks around the equator of the cell.
B)chromosomes are pulled toward the ends of the cell.
C)actin and microtubules constrict the cytoplasm.
D)new membrane and cell wall materials begin to grow and form a septum.

Question 15

A person whose cells all contain a chromosome number of 2n+1 most likely has what type of condition?

A)Monosomy
B)Trisomy
C)Cancer
D)Obesity

Question 16

In bacterial cell division, the cell divides into two nearly equal halves.This process is referred to as:

A)binary fission
B)mitosis
C)fusion
D)meiosis

Question 17

The two copies of each type of chromosome found in normal somatic (body) cells in an organism, throughout the cell cycle, are called:

A)Sister chromatids
B)Homologous chromosomes
C)Daughter chromosomes
D)Kinetochores

Question 18

Before cell division of somatic cells, each chromosome must be replicated.After replication, the resulting two parts of each chromosome are held together by cohesin at the centromere.These two parts are referred to as:

A)Sister chromatids
B)Homologous chromosomes
C)Daughter chromosomes
D)Kinetochores

Question 19

A scientist wants to study histones.Histones are:

A)proteins that double-stranded DNA molecules wrap around in eukaryotes.
B)proteins that double-stranded DNA molecules wrap around in prokaryotes and eukaryotes.
C)proteins that regulate checkpoints in the mitotic cell cycle.
D)proteins that serve as the spindle fiber to pull sister chromatids apart during anaphase.

Question 20

Eukaryotic chromosomes are composed of a complex of 60% protein and 40% DNA.This complex is referred to as:

A)The histone complex
B)Chromatin
C)The kinetochore
D)Cohesin

Question 21

What is the portion of the cell cycle during which the chromosomes are invisible under the light microscope because they are not yet condensed?

A)Interphase
B)Prophase
C)Metaphase
D)Anaphase

Question 22

Consider the cell cycle of a human cell.During G2, what is the state of the homologous chromosomes?

A)The homologous chromosomes are lined up on the equator of the cell.
B)The homologous chromosomes have all been copied through DNA replication and are beginning to condense.
C)The homologous chromosomes have been pulled to their respective poles by the spindle apparatus.
D)The homologous chromosomes have not been replicated yet.

Question 23

During this stage of mitosis, the nuclear envelope begins to break down and the spindle begins to form.

A)Anaphase
B)Metaphase
C)Prophase
D)Telophase

Question 24

This stage of the cell cycle is characterized by growth and it contains a checkpoint to verify that all of the DNA has been replicated prior to mitosis.

A)G₁
B)S
C)G₂
D)Mitosis

Question 25

During this stage of mitosis, the chromosomes become attached to the spindle at their kinetochores.

A)Prophase
B)Prometaphase
C)Metaphase
D)Anaphase

Question 26

This is the stage of mitosis characterized by the alignment of the chromosomes in a ring along the inner circumference of the cell:

A)Interphase
B)Telophase
C)Prophase
D)Metaphase

Question 27

The physical distribution of cytoplasmic material into the two daughter cells in plant cells is referred to as:

A)The gap phase
B)Cytokinesis
C)Binary fission
D)Interphase

Question 28

If a cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?

A)64
B)32
C)16
D)8

Question 29

In prophase, ribosomal RNA synthesis stops when the chromosomes condense, and as a result:

A)the chromosomes lengthen.
B)the nuclear envelope reforms.
C)the nucleolus disappears.
D)the chromosomes line up at the equator of the cell.

Question 30

The stage of mitosis characterized by the physical separation of sister chromatids is called:

A)Anaphase
B)Metaphase
C)Prometaphase
D)Telophase

Question 31

Interphase is made up of what stages of the cell cycle?

A)G₁ + G₂ + S
B)S + cytokinesis
C)prophase + metaphase + anaphase + telophase
D)cytokinesis + mitosis

Question 32

Following S phase, a human cell would have how many pairs of sister chromatids and individual DNA molecules?

A)23 pairs of sister chromatids and 46 individual DNA molecules
B)23 pairs of sister chromatids and 92 individual DNA molecules
C)46 pairs of sister chromatids and 46 individual DNA molecules
D)46 pairs of sister chromatids and 92 individual DNA molecules

Question 33

If a chromosome contains a mutation such that it cannot bind to the kinetochore complex, what would be the consequence?

A)That chromosome would not be able to be replicated.
B)That chromosome would not be able to condense.
C)That chromosome would not be able to bind to the mitotic spindle.
D)That chromosome would not be able to interact with histone proteins.

Question 34

Embryonic cell cycles allow the rapid division of cells in the early embryo.These mitotic cell cycles are much shorter in length than the mitotic cell cycles of cells in a mature organism.In the embryonic cell cycles, mitosis takes approximately the same amount of time as it does in the cell cycles of mature cells.What do you think is a result of the embryonic cycle?

A)Resulting daughter cells are smaller than the mother cell in the embryonic cell cycles.
B)Resulting daughter cells do not contain the same genetic information as the mother cell in the embryonic cell cycles.
C)Resulting daughter cells cannot form a mitotic spindle in the embryonic cell cycle.
D)Mother cells in the embryonic cell cycle spend the majority of their time in G_0.

Question 35

A duplicate copy of all of the hereditary information contained in the nucleus of eukaryotic cells is made during what stage of the cell cycle?

A)G₁
B)S
C)G₂
D)Mitosis

Question 36

During what stages of the cell cycle are sister chromatids bound together by cohesin?

A)G₁, S, G₂
B)S, G₂
C)G₁, S
D)S, G₂, prophase, metaphase

Question 37

What happens during Anaphase B?

A)Kinetochores are pulled toward the poles.
B)The spindle poles move apart.
C)The spindle apparatus disassembles.
D)The nuclear envelope reforms.

Question 38

What is the sequence of events in a typical eukaryotic cell cycle?

A)G1 to G2 to S to mitosis to cytokinesis
B)G1 to S to G2 to mitosis to cytokinesis
C)G1 to S to G2 to cytokinesis to mitosis
D)G1 to G2 to mitosis to S to cytokinesis

Question 39

This stage of mitosis is characterized by the disassembly of spindle apparatus, the reestablishment of the nuclear membrane, and the decondensation of the chromosomes:

A)Prometaphase
B)Telophase
C)Anaphase
D)Metaphase

Question 40

The portion of the cell cycle when the cell is growing and does not contain a replicated genome is referred to as:

A)G₁
B)S
C)G₂
D)Mitosis

Question 41

What is one of the roles of the APC/C during anaphase?

A)To directly target the mitotic cyclins for destruction.
B)To directly target cohesin for destruction.
C)To directly target separase for destruction.
D)To directly target microtubules for destruction.

Question 42

You are studying cell cycle progression in yeast cells.If you could prevent cdc2 from associating with the mitotic cyclin, the cells would:

A)arrest in G₁.
B)arrest in G₂.
C)arrest in S.
D)arrest in prometaphase.

Question 43

Plant cells typically achieve cytokinesis by:

A)binary fission.
B)forming a cell plate across the middle of the cell.
C)forming a cleavage furrow that pinches the cell into two.
D)chromosome condensation.

Question 44

You are leading a team of researchers at a pharmaceutical company.Your goal is to design drugs that help fight cancer.Specifically, you want to focus on drugs that bind to and inactivate certain proteins, thereby halting cell cycle progression.One of your team members suggests targeting the retinoblastoma (Rb) protein and inhibiting this protein.Will this approach be successful? Why or why not?

A)This approach will not be successful.Rb is tumor-suppressor protein, and functions to inhibit the action of a number of cell cycle regulatory proteins.A drug designed to inactivate the Rb protein would essentially create the same situation as in as a cell that lacks both copies of the Rb gene.Lack of Rb activity would release the inhibition of cell cycle regulatory proteins, thereby promoting cell cycle progression, rather than halting it.
B)This approach will be successful.Rb is an oncogene, and functions to activate a number of cell cycle regulatory proteins.A drug designed to inactivate the Rb protein would halt the cell cycle in cells that contain an active Rb.As a result, cancer cells expressing a constitutively active Rb protein would be good targets for this type of therapeutic.
C)This approach will be successful.Rb is tumor-suppressor protein, and functions to inhibit the action of a number of cell cycle regulatory proteins.A drug designed to inactivate the Rb protein would activate cell cycle inhibition.Lack of Rb activity would therefore inhibit the cell cycle regulatory proteins.
D)This approach will not be successful.Rb is an oncogene, and functions to activate a number of cell cycle regulatory proteins.A drug designed to inactivate the Rb protein would actually activate cell cycle progression.As a result, this drug would likely make this situation worse for patients whose cancer cells contain mutant Rb.

Question 45

You are studying cell cycle progression in an early frog embryo.If you were to inject a protein synthesis inhibitor into a cell during S phase, where do you predict that the cells would arrest?

A)G₁
B)G₂
C)Metaphase
D)Telophase

Question 46

You are conducting a genetic screen using Caenorhabditis elegans embryos to isolate mutations affecting anaphase (A).Therefore, you need to look for embryos in which

A)the centromeres do not move toward the poles.
B)the poles do not move apart.
C)the spindle apparatus does not disassemble.
D)sister chromatids are mismatched and therefore fail to separate.

Question 47

What stage of mitosis is essentially the reverse of prophase?

A)Anaphase
B)Prometaphase
C)Metaphase
D)Telophase

Question 48

The drug Taxol, or Paclitaxel, is used to treat patients with a variety of cancers, including breast, lung and ovarian cancers.The drug works by stabilizing microtubules, and preventing their disassembly.The goal of the drug is to prevent dividing cells from being able to complete mitosis.As a result, cancerous cells can no longer divide.In a cell treated with Taxol, at what stage of mitosis will the cells arrest?

A)Prior to metaphase
B)Anaphase
C)Telophase
D)Cytokinesis

Question 49

In G₂, there are typically high levels of the mitotic cyclin.Why is cdc2 not active during G₂ if the mitotic cyclin is present?

A)Cdc2 is also regulated by phosphorylation.
B)Cdc2 does not bind to the mitotic cyclin.
C)Cdc2 requires ubiquitination to be activated.
D)Cdc2 also has to bind to cohesin to be activated.

Question 50

The progress of the eukaryotic cell cycle is regulated primarily by what proteins?

A)Cyclins
B)Histone proteins
C)Condensins
D)FtsZ

Question 51

This protein or protein complex functions in the cell to stop cell division if the cell has experienced extensive DNA damage:

A)APC/C
B)p53
C)FtsZ
D)Condensin

Question 52

What would you expect to happen if the anaphase-promoting complex/cyclosome (APC/C) failed to ubiquitinate securin?

A)The cohesin complex will be destroyed, and the cell will remain in metaphase.
B)The cohesin complex will persist, preventing the cell from entering anaphase.
C)Separase will be marked for degradation by securin, preventing the cell from entering anaphase.
D)Securin will remain intact and therefore will degrade cohesin, allowing the cell to enter anaphase.

Question 53

If a cell was capable of bypassing metaphase and going directly from prometaphase to anaphase, what is the most likely consequence of this?

A)The resulting daughter cells would not have a nuclear envelope.
B)The resulting daughter cells would have significantly different quantities of cytoplasmic materials.
C)The resulting daughter cells would have different numbers of chromosomes.
D)The resulting daughter cells would be completely normal.

Question 54

If you were to think of the cell as a car, and mitosis as a process that drives that car to go, what would be a good analogy for a cell that has a mutation in both copies of a tumor-suppressor gene?

A)The gas pedal of a car gets stuck while pushed down.
B)The gas pedal of a car does not work at all.
C)The brake pedal of a car gets stuck while pushed down.
D)The brake pedal of a car does not work at all. Tumor suppressor genes are like the brakes on the cell cycle.Normally, they prevent cell division in response to problems, such as damaged DNA or incomplete replication.If both copies of a tumor suppressor gene are mutated, that would mean that a cell could not stop dividing in response to normal signals.This is analogous to cutting the brakes on a car.No matter what "signals" emerge (a stop sign, a red light, etc.), it is not possible to stop the car using the brake because there is something wrong with the brakes.

Question 55

Why is it so important that all of the chromosomes align on the metaphase plate during metaphase?

A)This is the only place in the cell where the cyclins and Cdks are located.
B)If they cannot, it suggests that they aren't properly attached to the spindle microtubules, and thus won't separate properly during anaphase.
C)This is the location where the chromosomes can become attached to the spindle microtubules.
D)This allows asters to form.

Question 56

You are examining the effect of maturation-promoting factor (MPF) in sea urchin cells, which have a diploid number of 36.If you fuse a dividing sea urchin cell with a G₁ arrested oocyte, what would be the outcome?

A)The G₁ cell would enter mitosis, but would likely arrest at the spindle checkpoint because the chromosomes have not been properly replicated.
B)The G₁ cell would undergo mitosis and its daughter cells would each have 36 chromosomes.
C)The G₁ cell would undergo mitosis and its daughter cells would each have 18 chromosomes.
D)The G₁ cell would first go through S phase and then mitosis.Its daughter cells would have 36 chromosomes.

Question 57

Animal cells typically achieve cytokinesis by:

A)binary fission.
B)forming a cell plate across the middle of the cell.
C)forming a cleavage furrow that pinches the cell into two.
D)chromosome condensation.

Question 58

At what checkpoint(s) does the cell arrest in response to DNA damage?

A)G₁/S
B)G₂/M
C)spindle
D)G₁/S and G₂/M

Question 59

What time point represents G₂?

A)1
B)2
C)3
D)4

Question 60

What is separase?

A)A protein that marks a protein called securin for destruction.
B)A protein that is part of the cohesin complex.
C)A protein that destroys cohesin through its protease activity.
D)A protein that targets the mitotic cyclin for degradation.