Deck 3: Genetic Influence on Cell Division, Differentiation, and Gametogenesis

Question 1

Which mechanism allows cell differentiation in embryonic tissue?

A)Increased expression of oncogenes
B)Decreased expression of suppressor genes
C)Selected expression of individual structural genes
D)Enhanced expression of promitotic transcription factors

Answer 1

Selected expression of individual structural genes

Question 2

How does apoptosis contribute to healthy organ and whole-body function?

A)Maintains telomeric DNA
B)Allows cells to differentiate rather than to undergo mitosis
C)Removes old or damaged cells from an organ population
D)Activates oncogenes when cells are damaged or necrotic

Answer 2

Removes old or damaged cells from an organ population

Question 3

Which event characterizes embryonic commitment?

A)Meiotic cell division
B)Selective loss of genes
C)Increased suppressor gene activity
D)Progressive increase in nuclear size

Answer 3

Increased suppressor gene activity

Question 4

What is the general purpose of tyrosine kinase enzymes?

A)Activating cyclins by phosphorylation
B)Increasing the amount of sodium-driven transcription factor activity
C)Suppressing the activation of oncogene expression
D)Uncovering growth factor receptor sites on plasma membranes

Question 5

What is the function of a suppressor gene product?

A)To ensure cell division occurs only when it is needed
B)To suppress the loss of differentiated functions with aging
C)To ensure the precise delivery of chromosomes to each new daughter cell
D)To prevent the formation of a large nuclear-to-cytoplasmic ratio during the G0 state

Question 6

Which normal cell characteristic is represented by the production of insulin in the beta cells of the pancreas?

A)Performance of a differentiated function
B)Ability to undergo apoptosis on schedule
C)Tight regulation of cell division
D)Conservation of energy

Question 7

How is apoptosis related to physiologic homeostasis?

A)The process prevents germline mutations.
B)The efficiency of organ/tissue functions is increased.
C)Replacement with scar tissue occurs more rapidly after cell damage.
D)Cells that are able to undergo apoptosis bypass restriction point controls for mitosis.

Question 8

Which stage of cell division is present in mitosis but is missing in meiosis?

A)G1
B)S
C)G2
D)M

Question 9

What would be the expected response to a skin injury if the involved tissue had lost the normal cell characteristic of contact inhibition?

A)Failure of the wound to close
B)Excessive growth of replacement tissue
C)Replacement with scar tissue rather than skin
D)Displacement of skin cells into other body tissues

Question 10

Normal cells spend most of their life spans in which phase?

A)G0
B)G1
C)S
D)M

Question 11

How do cyclins influence the process of cell division?

A)Suppressing oncogene products and inhibiting movement through the cell cycle
B)Generating transcription factors and promoting differentiated functions
C)Promoting apoptosis and allowing programmed cellular "suicide"
D)Opposing suppressor gene products and promoting cell division

Question 12

Which event occurs during mitosis?

A)Homologous chromosomes synapse and then cross over.
B)The number of chromosomes decreases from diploid to haploid.
C)Daughter cells are produced that are genetically identical to the parent cell.
D)DNA density decreases, and the 46 separate pieces assemble into one linear strand.

Question 13

Which feature or characteristic of early embryonic cells is unique in comparison with normal differentiated cells?

A)Diploidy
B)Pluripotency
C)Controlled cell division
D)Mitosis resulting in four new daughter cells

Question 14

What is the consequence for a tissue/cell that no longer produces any cell adhesion molecules?

A)The production of three daughter cells with mitosis instead of just two
B)Failure to perform any differentiated functions
C)Conversion from euploidy to aneuploidy
D)Migration of cells into other tissues

Question 15

How do transcription factors influence cell division?

A)They directly transmit external signals to the cell's nucleus.
B)Transcription factors regulate the expression of genes involved in cell division.
C)Loss or inactivation of transcription factors degrades suppressor gene protein products.
D)Transcription factors are enzymes that activate promitotic substances by adding a phosphate group to the chemical structure.

Question 16

In which phases of the cell cycle is the normal cell tetraploid (4N)?

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

Question 17

What is the expected result when two homologous chromosomes fail to separate during meiosis I of spermatogenesis?

A)Fertilization of this gamete may result in a zygote that is 48, XXYY.
B)One gamete will have two of these chromosomes, and one will have neither of these chromosomes.
C)The risk for development of polygenic disorders is increased with fertilization of the polar body associated with this mature gamete.
D)Increased genetic diversity is possible with fertilization of any of these four gametes because of an increased number of possible gene alleles.

Question 18

In what way is hypertrophic tissue growth more advantageous than hyperplastic tissue growth?

A)There is no limit to how large a tissue or organ can become.
B)It proceeds at the same rate throughout a person's life span.
C)Less energy is required for hypertrophic growth.
D)Differentiated functions change with aging.

Question 19

How many different genotypes are possible in any single mature spermatocyte of a man who is heterozygous at a single gene locus for a specific trait?

A)One
B)Two
C)Four
D)Eight

Question 20

Which cell feature is common to normal human differentiated cells and to early embryonic human cells?

A)Growth by hypertrophy
B)Contact inhibition
C)Tight adhesion
D)Euploidy

Question 21

What is the consequence of synapsis and crossing over?

A)Pure segregation of alleles along the metaphase plate
B)Tetraploidy, in which there are four copies of each chromatid
C)Diploidy of chromosome number and haploidy for DNA content
D)Random recombination of genetic material between paternal and maternal chromatids

Question 22

How many mature ovum result from the complete oogenesis of one oogonium?

A)One
B)Two
C)Three
D)Four

Question 23

Which cell division process sequences are normal for meiosis for gametogenesis?

A)Two rounds of DNA synthesis each followed by a separate round of meiotic cell division
B)Two rounds of DNA synthesis followed by two progressive rounds of meiotic cell division
C)A single round of DNA synthesis followed by two separate rounds of meiotic cell division
D)A single round of DNA synthesis first preceded by one round of meiotic cell division and then followed by a final round of meiotic cell division

Question 24

Why is normal fertilization of one mature ovum usually performed by only one mature sperm even though hundreds of millions of sperm are present in the seminalfluidofone ejaculation?

A)The corona radiata causes the tail of the other sperm to fall off, decreasing their motility.
B)At the time of first penetration, the pH around the ovum changes, and the enzymes of the other sperm are inactivated.
C)Fusion of the two nuclei forms a tight nuclear membrane that prevents the nuclei of other sperm from entering.
D)After being penetrated by one sperm, the ovum's membrane changes electrically and prevents other sperm from entering.

Question 25

Meiosis II of oocytes is completed at which developmental period?

A)At the ninth prenatal week
B)During puberty
C)At ovulation
D)At fertilization

Question 26

During which phase of gametogenesis is the process of crossing over more likely to occur for either spermatocytes or oocytes?

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

Question 27

Why is meiosis II for both spermatogenesis and oogenesis called an "equatorial division?"

A)The amount of cytoplasm in the secondary sex cells is evenly divided among the final cells.
B)The actual number of chromosomes within the resulting cells is the same as before this division.
C)Crossing over stops, and the bivalent chromosomes coil and condense in preparation for segregation.
D)The division of both the two secondary spermatocytes and the two secondary oocytes results in a total of eight gametes.

Question 28

Which cell in the process of oogenesis has the most chromosomes?

A)Mature ovum
B)Primary oocyte
C)Secondary oocyte
D)Polar body

Question 29

What is the usual outcome of "crossing over" during meiosis I for both spermatogenesis and oogenesis?

A)Unequal division of DNA between two new daughter cells during nucleokinesis
B)Mixing of maternal and paternal genes within one chromosome pair
C)Unequal distribution of cytoplasmic material
D)More rapid progression to meiosis II

Question 30

Which response is the immediate and direct result of fertilization?

A)Gamete chromosome reduction to the haploid number
B)Rapid proliferation of acrosomal and coronal cells
C)Primary sex determination of the zygote
D)Nuclear condensation

Question 31

Which process is unique to spermatogenesis?

A)Synapsis during the zygotene stage
B)Equal distribution of cytoplasm during meiosis I
C)Elongation of chromatids during the diplotene stage
D)Degeneration of germ cells between fetal life and the onset of puberty

Question 32

Why is fertilization of a polar body unlikely to lead to normal embryonic and fetal development?

A)The resulting zygote would be 4N instead of 2N.
B)The lack of cytoplasm would inhibit cellular reproduction.
C)The polar body has spent too long of a time trapped in meiosis I.
D)The resulting zygote would be smaller, which increases the risk for apoptosis.