Deck 3: Cell Division and Chromosome Heredity

Question 1

What insight did Nettie Stevens's studies of the beetle Tenebrio molitor provide about the chromosome theory of inheritance?

A)Genes are located on chromosomes.
B)The number of autosomal chromosomes varied between gametes.
C)Crossing over occurs between homologous chromosomes.
D)Sex is determined by the presence of an X or Y chromosome in the male gamete.
E)Chromosomes assort independently into the haploid gametes.

Answer 1

D

Question 2

The binding of nonsister chromatids by a synaptonemal complex draws the homologs into close contact so that what process can occur?

A)cytokinesis
B)karyokinesis
C)independent assortment
D)synapsis
E)disjunction

Answer 2

D

Question 3

If you mutate the cyclin-binding site on a Cdk such that Cdk cannot bind to cyclin,what effect would you expect to see?

A)Cdk will be unaffected.
B)The cell cycle will be up-regulated,and cells will proliferate.
C)Cdk will be inactive,so the target proteins will not be phosphorylated.
D)Cdk will be constitutively active,so the cell cycle will be unchecked.
E)Cdk will phosphorylate its target proteins regardless of the cell cycle.

Answer 3

C

Question 4

Which structure is responsible for chromosome movement during cell division?

A)synaptonemal complex
B)kinetochore microtubules
C)metaphase plate
D)nuclear envelope
E)cell membrane

Question 5

How do protein kinases generally activate their target proteins?

A)The process of phosphorylation causes the target to change conformation.
B)The kinases bind to target proteins directly,forming a complex that activates the protein and lets them change conformations.
C)Kinases vary their concentrations through the cell cycle,so that proteins are activated only when kinase levels are high.
D)Kinases bind to target proteins and inactivate them,so kinase levels must drop for target protein activation.
E)The process of dephosphorylation causes the target to change conformations.

Question 6

Tumor suppressors are genes that

A)promote advancement of the cell cycle.
B)phosphorylate proteins involved in the cell cycle.
C)block progression of the cell cycle.
D)prevent apoptosis in normal cells.
E)activate proto-oncogenes.

Question 7

Certain kinds of cells (e.g.,some cells in the eyes and bones)mature and differentiate into a state in which they have a specialized function but do not divide or progress through the cell cycle.These cells are "stuck" in which stage?

A)M phase
B)G₁
C)G₂
D)S
E)G₀

Question 8

During which stage or phase of the cell cycle does the cell actively transcribe and translate all the protein products necessary for normal cellular structure and function?

A)M phase
B)G₁
C)G₂
D)S
E)G₀

Question 9

During meiosis I,when does homologous chromosome pairing and recombination occur?

A)prophase I
B)pro-metaphase I
C)metaphase I
D)anaphase I
E)telophase I

Question 10

After which stage or phase of the cell cycle does the cell divide?

A)M phase
B)G₁
C)G₂
D)S
E)G₀

Question 11

Mutations that inhibit Rb gene expression will have what effect on cell proliferation?

A)Cells will proliferate less,even if excess growth factors are present.
B)Cells will proliferate less because growth factors are absent.
C)Cells will proliferate more because growth factors are produced in excess.
D)Cells will proliferate more,regardless of growth factor concentration.
E)There will be no effect on cell proliferation;only apoptosis occurs.

Question 12

The separation of sister chromatids during anaphase I of mitosis is known as chromosome

A)cytokinesis.
B)karyokinesis.
C)crossing over.
D)synapsis.
E)disjunction.

Question 13

During which stage or phase of the cell cycle does the cell replicate its chromosomes?

A)M phase
B)G₁
C)G₂
D)S
E)G₀

Question 14

Morgan's analysis of a white-eyed male Drosophila mutation helped explain

A)autosomal dominance.
B)random mutation.
C)crossing over.
D)independent assortment.
E)X-linked inheritance.

Question 15

Which organelle migrates during M phase to form the two opposite poles of the dividing cell and acts as the source of the spindle fiber microtubules?

A)centromere
B)kinetochore
C)centrosome
D)chiasmata
E)chromosome

Question 16

Contact points between nonsister chromatids that mark the locations of DNA-strand exchange are called

A)synaptonemal complex.
B)metaphase plate.
C)chiasmata.
D)kinetochore.
E)centrosome.

Question 17

During cell division,chromosomal material is improperly divided between the two daughter cells such that one cell receives three copies of a chromosome,and the other cell receives only one.This is likely due to a defect in which process?

A)cytokinesis
B)karyokinesis
C)crossing over
D)synapsis
E)homologous recombination

Question 18

Bridges showed that sex determination in Drosophila meant that

A)females were XX or XXX,and males were XY or XXY.
B)females were XX,and males were XY.
C)females were XX,and males were XY or XO.
D)females were XX or XXX,and males were XY or XO.
E)females were XX or XO,and males were XY or XXY.

Question 19

Mitosis is a process of cell division that results in

A)two unique daughter cells.
B)four unique daughter cells.
C)two identical daughter cells.
D)three identical daughter cells.
E)four identical daughter cells.

Question 20

Vinblastine is a commonly used chemotherapy drug that acts by interfering with the assembly of microtubules.How does it likely target cancer cells?

A)by suppressing cyclins
B)by inhibiting protein kinases
C)by inhibiting DNA synthesis
D)by denaturing myosin and preventing the cleavage furrow from forming
E)by disrupting mitotic spindle formation

Question 21

In meiosis I,the diploid number (2n)of chromosomes is reduced to the haploid number (n)because of the separation of what?

Question 22

The five substages of M phase are designed to accomplish two main goals equal partitioning of chromosomal material and cytoplasmic contents between the two cells.What are these two processes called?

Question 23

What process is used to make mature germ-line cells,or gametes?

Question 24

How many chromosomes are found in a human somatic cell nucleus?

Question 25

How many homologous pairs of chromosomes are found in a human somatic cell nucleus?

Question 26

Microtubules are polar and have a plus and a minus end.Which end is anchored at the centrosome?

Question 27

The gametes of the two sexes are often dramatically different in size and morphology.Both gametes have a haploid nucleus,so what do female gametes contain more of?

Question 28

If a trait is X-linked recessive,who would express the trait?

A)homozygous dominant females and hemizygous recessive males
B)heterozygous recessive females and hemizygous dominant males
C)homozygous recessive females and hemizygous recessive males
D)heterozygous dominant females and hemizygous dominant males
E)the same proportions of females and males

Question 29

In meiosis II,sister chromatids separate and produce what?

Question 30

Why are chromosomes more easily visible under the microscope during metaphase as compared to prophase?

Question 31

At the end of the G₁ stage,cells have the option of entering which two phases?

Question 32

When cyclin D1 is expressed in normal levels,it stimulates the cell cycle.If overexpressed,it can promote cancer by allowing cells to overproliferate.A normal gene with the potential to cause cancer if mutated and/or overexpressed is known as what?

Question 33

Single-celled eukaryotes can survive and reproduce in both haploid and diploid forms.Yeast spend most of their life cycle and actively reproduce in which form?

Question 34

The number of recombination nodules along each homologous chromosome arm correlates closely with the average number of what?

Question 35

What dosage compensation mechanism is employed by female placental mammals?

A)synteny
B)Y-inactivation
C)X-inactivation
D)X nondisjunction
E)X chromosome crossing over

Question 36

If a trait is X-linked dominant,who would express the trait?

A)homozygous dominant females and hemizygous recessive males
B)heterozygous recessive females and hemizygous dominant males
C)homozygous recessive females and hemizygous recessive males
D)heterozygous dominant females and hemizygous dominant males
E)significantly more females than males

Question 37

What is the short segment of the cell cycle during which cells divide?

Question 38

Protein kinases help phosphorylate target proteins,but they are present in relatively constant concentrations throughout the cell cycle.Which proteins,which vary through the cell cycle,form a complex with the kinases to activate them only at specific times?

Question 39

How many sister chromatids are found in a human somatic cell nucleus during mitosis?

Question 40

If a cell begins to divide rapidly (as often seen in wound repair),what would you expect to happen to the G₁ stage?

Question 41

Any mechanism that compensates for differences in the number of copies of genes due to the different chromosome constitutions of males and females is called what?

Question 42

Describe how microtubules and cohesion work together to align the chromosomes along the metaphase plate during the process of sister chromatid cohesion.

Question 43

What is the mammalian transcription factor that elicits a cascade of gene transcription and developmental events that ultimately produce male internal and external structures?

Question 44

Synapsis initiates formation of a protein bridge called the synaptonemal complex,a tri-layer protein structure that maintains synapsis by tightly binding ________ of homologous chromosomes to one another.

Question 45

What are the three important differences between mitosis and meiosis I?

Question 46

Females have two copies of the X chromosome,so they can be homozygous or heterozygous for any genes found on the X chromosome.Males have only one copy of the X chromosome;what term is used to describe this inheritance state?

Question 47

According to Bridges's proposal,exceptional phenotypes and unusual karyotypes were the result of rare mistakes in meiosis caused by the failure of X chromosomes to separate properly in either the first or second meiotic division in females.What term is used in referring to this phenomenon?

Question 48

How do cyclin-dependent kinases help regulate the cell cycle?

Question 49

The ________ number,or n,is the number of chromosomes contained in the nuclei of gametes,the nonsomatic cells.

Question 50

What is the difference between cytokinesis and karyokinesis? Which process needs to be more precise for accurate cell division?

Question 51

The ________ varies among species (each species has its characteristic number of pairs)and is identified nonspecifically as 2n.

Question 52

In meiosis,interphase is followed by two successive rounds of cell division,meiosis I and II.Meiosis results in four haploid daughter cells because there is no ________ between these two meiotic cell divisions.

Question 53

Of the trillions of cells in the human body,most are ________,the cells that form organs and tissues.

Question 54

This protein assures that sister chromatids of each chromosome remain firmly joined and can resist the pull of the kinetochore microtubules.