Question 1

Choose the statement that is true of meiosis, considering the entire process and the events of all stages. 
A)During prophase II, chromosomes re-replicate themselves to form a diploid cell and condense.
B)Sex cells go from being diploid to haploid during meiosis I.
C)Crossover occurs during anaphase I.
D)During anaphase II, the two homologous chromosomes are separated and pulled to opposite ends of the cell.

Accepted Answer

A

Question 2

The epithelium of the seminiferous tubules consists of
A)adipose cells and chondrocytes.
B)spermatogenic cells and sustentacular cells.
C)spermatogonia and spermatids.
D)interstitial cells and sustentacular cells.

Accepted Answer

The seminiferous tubules consist of two main types of cells: spermatogenic cells, which are responsible for sperm production, and sustentacular cells (also called Sertoli cells), which support and nourish the spermatogenic cells. Therefore, the epithelium of the seminiferous tubules consists of spermatogenic cells and sustentacular cells.

Question 3

Semen
A)consists of sperm and accessory organ secretions and not testicular products.
B)is acidic.
C)includes prostaglandins and nutrients.
D)is produced by only one organ.

Accepted Answer

Semen is a complex mixture that includes sperm from the testes, as well as secretions from several accessory organs, including the seminal vesicles, prostate gland, and bulbourethral glands. These secretions contain prostaglandins, which help sperm motility and viability, and nutrients to support the sperm on their journey.

Question 4

What would be true of the newly formed sex cells in a person possessing a mutation that completely prevents crossover? 
A)The new cells would have less genetic variability because crossing over contributes to proper chromosome shape, so parts of the chromosome would be non-functional.
B)The new cells would have less genetic variability because whole chromosomes would only be entirely maternal or paternal.
C)The new cells would have more genetic variability because crossing over limits transmission of maternal and paternal genes.
D)The new cells would contain abnormal chromosome numbers because crossing over ensures proper division.

Accepted Answer

Without crossover, the homologous chromosomes would segregate independently during meiosis, resulting in whole chromosomes being entirely maternal or paternal. This would decrease the amount of genetic variability in the newly formed sex cells.

Question 5

The number of possible chromosome combinations in a gamete of a human is
A)800.
B)8,000.
C)80,000.
D)8 million.

Accepted Answer

A human gamete contains 23 chromosomes, and each chromosome can have different versions (alleles) of genes. As a result, the total number of possible chromosome combinations in a human gamete is 2^23, which equals approximately 8 million. Therefore, choice D is the most accurate answer. The other choices significantly underestimate the number of possible combinations.

Question 6

The number of sperm cells that form from a primary spermatocyte is
A)4.
B)16.
C)46.
D)100.

Accepted Answer

A primary spermatocyte undergoes meiosis I, which results in the formation of two haploid secondary spermatocytes. Each secondary spermatocyte then undergoes meiosis II to yield two haploid spermatids, resulting in a total of four sperm cells per primary spermatocyte. Therefore, the correct choice is A) 4.

Question 7

In a certain male individual, primary spermatocytes do not divide into secondary spermatocytes, yet still undergo spermiogenesis and form mature sperm. These sperm then fertilize a normal oocyte. What will be true of the zygote?
A)The zygote will have 46 chromosomes instead of 23.
B)The zygote will be diploid instead of haploid.
C)The zygote will have 69 chromosomes instead of 46.
D)The zygote will have only paternal chromosomes.

Accepted Answer

Normally, primary spermatocytes undergo meiosis I to form two haploid secondary spermatocytes, each of which then undergoes meiosis II to produce haploid spermatids that mature into sperm. If primary spermatocytes do not divide into secondary spermatocytes but still form mature sperm, these sperm would retain the diploid number of chromosomes (46 in humans) instead of the haploid number (23). When such a diploid sperm fertilizes a normal haploid oocyte (23 chromosomes), the resulting zygote would have 69 chromosomes (46 from the sperm + 23 from the oocyte), making option C correct.

Question 8

A man chooses to become sterilized via vasectomy. How will this affect interstitial cells?
A)Injury to the ductus differentia signals for interstitial cells to stop nourishing spermatogenic cells.
B)The procedure of a vasectomy only blocks the movement of sperm through the ductus deferens and won't affect interstitial cells.
C)Interstitial cells lining the ductus deferens stop producing alkaline secretions, killing sperm as they travel through.
D)The vasectomy causes secretions that interrupt testosterone secretion from interstitial cells.

Accepted Answer

A vasectomy only blocks the transportation of sperm through the ductus deferens and does not directly affect interstitial cells. These cells are responsible for secreting testosterone, which is not involved in the process of sperm transportation.

Question 9

Which of the following structures is unpaired?
A)Seminal vesicle
B)Ductus deferens
C)Bulbourethral gland
D)Prostate gland

Accepted Answer

The prostate gland is a single, unpaired structure located below the bladder in males, whereas the other options are paired structures.

Question 10

During the first meiotic division
A)sperm and egg form.
B)homologous chromosome pairs separate.
C)homologous chromosome pairs join.
D)the cell becomes diploid.

Accepted Answer

During the first meiotic division, homologous chromosome pairs separate, which results in the reduction of the chromosome number by half. This process is also known as reduction division.

A is incorrect because the formation of sperm and egg occurs during meiosis II.

C is incorrect because in the first meiotic division, homologous chromosomes separate instead of joining.

D is incorrect because the first meiotic division results in the formation of haploid cells, which means that the chromosome number is reduced by half, rather than doubled.

Question 11

In a certain male individual, primary spermatocytes do not divide into secondary spermatocytes, yet still undergo spermiogenesis and form mature sperm. How will the resulting sperm differ from normal sperm? 
A)The abnormal sperm will have 23 chromosomes instead of 46.
B)The abnormal sperm will be diploid instead of haploid.
C)The abnormal sperm won't develop a tail or acrosomal cap.
D)The abnormal sperm are all type A cells.

Accepted Answer

Normal spermatogenesis involves the division of primary spermatocytes (which are diploid) into secondary spermatocytes (which are haploid) through meiosis I. If this division does not occur, the resulting sperm would retain the diploid number of chromosomes (46) instead of the normal haploid number (23).

Question 12

A man is exposed to a virus which specifically targets and kills sustentacular cells (Sertoli cells). What effect will this have on spermatogenesis?
A)Spermatogenic cells will starve and cease development because they won't receive the nutrients or support they need.
B)Sperm cells will not mature because spermiogenesis will not occur after meiosis.
C)Spermatogonia will not be stimulated to divide because of lack of testosterone secretion.
D)Mature sperm won't be loaded with enough ATP to fuel flagellar movement.

Accepted Answer

Sustentacular cells (Sertoli cells) provide nutrients and support for developing sperm cells during spermatogenesis. If they are destroyed by a virus, spermatogenic cells will starve and cease development due to lack of nutrients and support.

Question 13

The gubernaculum guides the testis through the ________ canal.
A)penile
B)pelvic
C)inguinal
D)seminiferous

Accepted Answer

The gubernaculum is a cord-like structure that guides the testis during fetal development through the inguinal canal and into the scrotum. Therefore, the correct answer is C) inguinal canal.

Question 14

Meiosis is necessary because
A)otherwise the fertilized ovum will have too much genetic material.
B)otherwise the fertilized ovum will have too little genetic material.
C)otherwise reproduction would have to be asexual.
D)otherwise too many mutations will occur.

Accepted Answer

Meiosis is necessary to ensure that the genetic material in the fertilized ovum is halved and that the resulting individual has the correct amount of genetic material. Without meiosis, the fertilized ovum would have too much genetic material, leading to developmental defects and other issues. Meiosis also ensures genetic diversity in offspring, which is critical for evolution and adaptation. Therefore, choice A is the best answer.

Question 15

The bulbourethral glands secrete
A)sperm.
B)a mucus-like fluid.
C)blood.
D)sweat.

Accepted Answer

The bulbourethral glands secrete a mucus-like fluid that helps lubricate the urethra and neutralizes any acidity in the urethra, which can help protect the sperm as they pass through during ejaculation.

Question 16

The head of a sperm is mostly
A)mitochondria.
B)cell membrane.
C)cytoskeleton.
D)nucleus.

Accepted Answer

The head of a sperm contains the nucleus, which carries the genetic material. The other structures like mitochondria, cell membrane or cytoskeleton are either present in small amounts or are entirely absent.

Question 17

During meiosis II, one spindle fiber fails to attach to a chromosome at the centromere. How will this affect the genetic content of the daughter cells?
A)One daughter cell will have two chromosomes and the other daughter cell will have no chromosomes.
B)One daughter cell will have only maternal genes and the other daughter cell will have only paternal genes.
C)One daughter cell will contain one extra chromosome and the other daughter cell will have one less of that chromosome.
D)One daughter cell will have three copies of a chromosome and the other daughter cell will have two copies of that chromosome.

Accepted Answer

The failure of one spindle fiber to attach to a chromosome means that during meiosis II, that chromosome will not be pulled apart properly. This results in one daughter cell having an extra chromosome (due to not receiving one during meiosis II) and the other daughter cell having one fewer chromosome (due to receiving two copies of that chromosome during meiosis II). This situation is known as nondisjunction.

Question 18

The number of sperm cells in an ejaculate averages
A)about 20 million per milliliter.
B)about 20 million per millimeter.
C)about 20 million per liter.
D)about 120 million per milliliter.

Accepted Answer

The average number of sperm cells in an ejaculate is about 120 million per milliliter. This high concentration is necessary for increasing the chances of fertilization.

Question 19

Synapsis occurs during
A)prophase I.
B)metaphase I.
C)anaphase I.
D)telophase I.

Accepted Answer

Synapsis is the pairing of homologous chromosomes, which occurs during prophase I of meiosis.

Question 20

Identify the correct sequence for the steps of meiosis I.
A)Interphase-mitosis-meiosis
B)Telophase I-anaphase I-metaphase I-prophase I
C)46 chromosomes-23 chromosomes-then 46 chromosomes
D)Prophase I-metaphase I-anaphase I-telophase I

Accepted Answer

Meiosis I consists of Prophase I, Metaphase I, Anaphase I, and Telophase I in that sequence. Option A is incorrect because mitosis is not a part of meiosis I. Option B has the correct order of phases but is referring to Meiosis II. Option C is incorrect because it is not in the correct order, and the event described is not specific to meiosis I. Option D has the correct sequence of events specific to Meiosis I.

Quiz 22: Reproductive Systems

Choose the statement that is true of meiosis, considering the entire process and the events of all stages.

The epithelium of the seminiferous tubules consists of

Semen

What would be true of the newly formed sex cells in a person possessing a mutation that completely prevents crossover?

The number of possible chromosome combinations in a gamete of a human is

The number of sperm cells that form from a primary spermatocyte is

In a certain male individual, primary spermatocytes do not divide into secondary spermatocytes, yet still undergo spermiogenesis and form mature sperm. These sperm then fertilize a normal oocyte. What will be true of the zygote?

A man chooses to become sterilized via vasectomy. How will this affect interstitial cells?

Which of the following structures is unpaired?

During the first meiotic division

In a certain male individual, primary spermatocytes do not divide into secondary spermatocytes, yet still undergo spermiogenesis and form mature sperm. How will the resulting sperm differ from normal sperm?

A man is exposed to a virus which specifically targets and kills sustentacular cells (Sertoli cells) . What effect will this have on spermatogenesis?

The gubernaculum guides the testis through the ________ canal.

Meiosis is necessary because

The bulbourethral glands secrete

The head of a sperm is mostly

During meiosis II, one spindle fiber fails to attach to a chromosome at the centromere. How will this affect the genetic content of the daughter cells?

The number of sperm cells in an ejaculate averages

Synapsis occurs during

Identify the correct sequence for the steps of meiosis I.