Question 1

Which event characterizes embryonic commitment?&#10;A)Meiotic cell division&#10;B)Selective loss of genes&#10;C)Increased suppressor gene activity&#10;D)Progressive increase in nuclear size

Accepted Answer

Commitment involves adjusting the activity of the promitotic oncogenes and the genes that regulate differentiation. Suppressor gene activity increases so that greater control and limits are placed on oncogenes, usually slowing cell division somewhat. In addition, whatever genes are important for structure and function within specific organs are selectively expressed, but no genes are lost from any cell type. Meiotic cell division occurs later in fetal life for females and not until puberty for males. It is not a function of commitment. With commitment and change in cell division, the nuclear size decreases.

Question 2

In what way is hypertrophic tissue growth more advantageous than hyperplastic tissue growth?&#10;A)There is no limit to how large a tissue or organ can become.&#10;B)It proceeds at the same rate throughout a person's life span.&#10;C)Less energy is required for hypertrophic growth.&#10;D)Differentiated functions change with aging.

Accepted Answer

Hypertrophic growth involves an increase in cell size, whereas hyperplastic growth involves an increase in cell number. It is more advantageous because it requires less energy compared to hyperplastic growth, where new cells must be produced and maintained. Additionally, hypertrophic growth can reach a limit to prevent oversized organs or tissues that may compromise their function.

Question 3

How do cyclins influence the process of cell division?&#10;A)Suppressing oncogene products and inhibiting movement through the cell cycle&#10;B)Generating transcription factors and promoting differentiated functions&#10;C)Promoting apoptosis and allowing programmed cellular &#34;suicide&#34;&#10;D)Opposing suppressor gene products and promoting cell division

Accepted Answer

Cyclins are proteins that regulate the progression of the cell cycle by activating cyclin-dependent kinases (CDKs). CDKs promote cell division by phosphorylating target proteins such as retinoblastoma protein (Rb), allowing the cell to progress through the cell cycle. Cyclins can also activate other proteins that oppose the actions of tumor suppressor genes, thus promoting cell division. Therefore, choice D is the best choice.

Question 4

Why is meiosis II for both spermatogenesis and oogenesis called an equatorial division?&#10;A)The amount of cytoplasm in the secondary sex cells is evenly divided among the final cells.&#10;B)The actual number of chromosomes within the resulting cells is the same as before this division.&#10;C)Crossing over stops and the bivalent chromosomes coil and condense in preparation for segregation.&#10;D)The division of both the two secondary spermatocytes and the two secondary oocytes results in a total of eight gametes.

Accepted Answer

For both ova and sperm, meiosis II is a relatively rapid process. This division is an equational division because the number of chromosomes remains the same (23), although the DNA content was diploid before the division and haploid after the division.

Question 5

Which normal cell characteristic is represented by the production of insulin in the beta cells of the pancreas?&#10;A)Performance of a differentiated function&#10;B)Ability to undergo apoptosis on schedule&#10;C)Tight regulation of cell division&#10;D)Conservation of energy

Accepted Answer

The production of insulin in the beta cells of the pancreas represents the performance of a differentiated function, which is a normal cell characteristic.

Question 6

What is the consequence for a tissue/cell that no longer produces any cell adhesion molecules?&#10;A)The production of three daughter cells with mitosis instead of just two&#10;B)Failure to perform any differentiated functions&#10;C)Conversion from euploidy to aneuploidy&#10;D)Migration of cells into other tissues

Accepted Answer

Most normal cells have cell adhesion molecules, which are cell surface proteins that allow normal cells of the same type to adhere tightly together. As a result, they are not migratory. Without cell adhesion molecules, tissues and organs would have a looser construction in which cells could break off and migrate into other body areas. Cell adhesion molecules have little effect on the performance of differentiated functions and do not regulate the chromosome number of a cell. Normal cell division does not result in the formation of three new daughter cells regardless of whether cell adhesion molecules are present or are not present.

Question 7

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?&#10;A)One&#10;B)Two&#10;C)Four&#10;D)Eight

Accepted Answer

The mature spermatocyte is haploid, with only one chromosome of each pair present. It should have only one gene allele. Even though the person is heterozygous for a single gene trait and his diploid cells have two alleles, each mature spermatocyte will have only one. In about half of the mature spermatocytes, one specific allele of the two is present. In the rest of the mature spermatocytes, the other specific allele is present.

Question 8

How is apoptosis related to physiologic homeostasis?&#10;A)The process prevents germline mutations.&#10;B)The efficiency of organ/tissue functions is increased.&#10;C)Replacement with scar tissue occurs more rapidly after cell damage.&#10;D)Cells that are able to undergo apoptosis bypass restriction point controls for mitosis.

Accepted Answer

Apoptosis, or programmed cell death, is a crucial mechanism for maintaining physiologic homeostasis. It helps to eliminate damaged or abnormal cells, which in turn improves the efficiency of organ and tissue functions. This ensures that the body is able to function optimally and helps to prevent the development of diseases.

Question 9

Normal cells spend most of their life spans in which phase? A)G₀ B)G₁ C)S D)M

Accepted Answer

Normal cells spend most of their life spans in the G0 phase, which is a resting phase in which the cell does not divide.

Question 10

During which phase of gametogenesis is the process of crossing over more likely to occur for either spermatocytes or oocytes?&#10;A)Metaphase I&#10;B)Interphase I&#10;C)Anaphase I&#10;D)Prophase I

Accepted Answer

Crossing over occurs during prophase I of meiosis, which is the longest and most complex phase of meiosis. This is when homologous chromosomes pair up and exchange genetic information, which increases genetic diversity in the resulting gametes. Therefore, the best choice is D, Prophase I, for both spermatocytes and oocytes.

Question 11

Which feature or characteristic of early embryonic cells is unique in comparison with normal differentiated cells?&#10;A)Diploidy&#10;B)Pluripotency&#10;C)Controlled cell division&#10;D)Mitosis resulting in four new daughter cells

Accepted Answer

The answer of Which feature or characteristic of early embryonic...

Question 12

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 formation of a large nuclear-to-cytoplasmic ratio during the G₀ state

Accepted Answer

The answer of What is the function of a suppressor...

Question 13

What is the expected result when two homologous chromosomes fail to separate during meiosis I of spermatogenesis?&#10;A)Fertilization of this gamete may result in a zygote that is 48,XXYY.&#10;B)One gamete will have two of these chromosomes and one will have neither of these chromosomes.&#10;C)The risk for development of polygenic disorders is increased with fertilization of the polar body associated with this mature gamete.&#10;D)Increased genetic diversity is possible with fertilization of any of these four gametes because of an increased number of possible gene alleles.

Accepted Answer

The answer of What is the expected result when two...

Question 14

What would be the expected response to a skin injury if the involved tissue had lost the normal cell characteristic of contact inhibition?&#10;A)Failure of the wound to close&#10;B)Excessive growth of replacement tissue&#10;C)Replacement with scar tissue rather than skin&#10;D)Displacement of skin cells into other body tissues

Accepted Answer

The answer of What would be the expected response to...

Question 15

What is the consequence of synapsis and crossing over?&#10;A)Pure segregation of alleles along the metaphase plate&#10;B)Tetraploidy in which there are four copies of each chromatid&#10;C)Diploidy of chromosome number and haploidy for DNA content&#10;D)Random recombination of genetic material between paternal and maternal chromatids

Accepted Answer

The answer of What is the consequence of synapsis and...

Question 16

How many mature ovum result from the complete oogenesis of one oogonium?&#10;A)One&#10;B)Two&#10;C)Three&#10;D)Four

Accepted Answer

The answer of How many mature ovum result from the...

Question 17

Which cell division process sequences are normal for meiosis for gametogenesis?&#10;A)Two rounds of DNA synthesis each followed by a separate round of meiotic cell division&#10;B)Two rounds of DNA synthesis followed by two progressive rounds of meiotic cell division&#10;C)A single round of DNA synthesis followed by two separate rounds of meiotic cell division&#10;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

Accepted Answer

The answer of Which cell division process sequences are normal...

Question 18

Which stage of cell division is present in mitosis but is missing in meiosis? A)G₁ B)S C)G₂ D)M

Accepted Answer

The answer of Which stage of cell division is present...

Question 19

Which response is the immediate and direct result of fertilization?&#10;A)Gamete chromosome reduction to the haploid number&#10;B)Rapid proliferation of acrosomal and coronal cells&#10;C)Primary sex determination of the zygote&#10;D)Nuclear condensation

Accepted Answer

The answer of Which response is the immediate and direct...

Question 20

Which event occurs during mitosis?&#10;A)Homologous chromosomes synapse and then cross over&#10;B)The number of chromosomes decreases from diploid to haploid&#10;C)Daughter cells are produced that are genetically identical to the parent cell&#10;D)DNA density decreases and the 46 separate pieces assemble into one linear strand

Accepted Answer

The answer of Which event occurs during mitosis?&#10;A)Homologous chromosomes synapse...

Question 21

Meiosis II of oocytes is completed at which developmental period?&#10;A)At the ninth prenatal week&#10;B)During puberty&#10;C)At ovulation&#10;D)At fertilization

Accepted Answer

The answer of Meiosis II of oocytes is completed at...

Question 22

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 seminal fluid of one ejaculation?&#10;A)The corona radiata causes the tail of the other sperm to fall off,decreasing their motility.&#10;B)At the time of first penetration the pH around the ovum changes and the enzymes of the other sperm are inactivated.&#10;C)Fusion of the two nuclei forms a tight nuclear membrane that prevents the nuclei of other sperm from entering.&#10;D)After being penetrated by one sperm,the ovum's membrane changes electrically and prevents other sperm from entering.

Accepted Answer

The answer of Why is normal fertilization of one mature...

Deck 3: Genetic Influences on Cell Growth, cell Differentiation, and Gametogenesis