AP Biology : Understanding Gametogenesis

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #281 : Systems Physiology

Where does the human body store spermatozoa?

Possible Answers:

Seminal vesicle

Epididymis

Ejaculatory duct

Seminiferous tubules

Correct answer:

Epididymis

Explanation:

Spermatozoa are stored in the epididymis prior to ejaculation. Prior to entering the epididymis, spermatozoa are immotile; however, as they travel through the epididymis the cells mature and gain motility.

Example Question #51 : Reproductive Physiology

Which of the following best describes how a sperm's axoneme develops during spermiogenesis?

Possible Answers:

Mitochondrial clustering

Microtubule growth from a single centriole

DNA condensation

Rearrangement of the Golgi apparatus

Correct answer:

Microtubule growth from a single centriole

Explanation:

Spermiogenesis is the final stage of spermatogenesis. In the process of spermiogenesis, spermatids develop into spermatozoa and form axoneme—the internal structure of the spermatozoa tails. It develops by way of microtubule growth from a single centriole that constructs the internal structure of the sperm tail. Mature spermatozoa have axonemes comprised of nine outer microtubule doublets and two central microtubules. These structures aid in motility.

Example Question #52 : Reproductive Physiology

In the process of spermiogenesis, the acrosome is derived from which of the following organelles?

Possible Answers:

Golgi apparatus

Centriole

Endoplasmic reticulum

Cytoplasm

Correct answer:

Golgi apparatus

Explanation:

Spermiogenesis is the final stage of spermatogenesis. In mature spermatozoa, the acrosome is the head of the cell and, in humans, contains digestive enzymes for ovum penetration. The acrosome develops during spermiogenesis when the Golgi apparatus surrounds the nucleus. 

Example Question #1254 : Ap Biology

Which of the following best describes where mitochondria are localized in spermatozoa?

Possible Answers:

Around the axoneme

At the acrosome

Near condensed DNA

At the plasma membrane

Correct answer:

Around the axoneme

Explanation:

Mitochondria cluster around the axoneme during spermiogenesis. They supply the energy needed for sperm movement, which is achieved through movement of the flagellum.

Example Question #291 : Systems Physiology

Which of the following best represents the effect of high testosterone concentrations within the seminiferous tubules that occurs during spermiogenesis?

Possible Answers:

Aids in the development of sperm motility

Removes excess cytoplasm

Removes excess organelles

Aids in axoneme formation

Correct answer:

Removes excess organelles

Explanation:

There is a high concentration of testosterone within the seminiferous tubules. The secretion of androgen-binding protein by Sertoli cells concentrates testosterone around cells undergoing spermiogenesis, The testosterone aids in the process of sperm maturation by removing excess organelles from the developing spermatozoa. 

Example Question #292 : Systems Physiology

Which of the following choices describes how the human body manages the heat sensitivity of the seminiferous tubules in order to protect the process of spermiogenesis?

Possible Answers:

Hormones lower the temperature in the testes

It places the testes outside of the body

It reduces catalytic activity 

Spermatozoa are immotile in the seminiferous tubules

Correct answer:

It places the testes outside of the body

Explanation:

The seminiferous tubules and developing spermatozoa within them are temperature-sensitive; they cannot tolerate high temperatures—including the temperature of the human body. In order to manage this, the testes are located outside of the human body in a sac of skin called the scrotum. This lowers the temperature of the seminiferous tubules to optimal levels. 

Example Question #291 : Systems Physiology

Where does the process of spermatogenesis occur in humans?

Possible Answers:

Ejaculatory duct

Seminal vesicle

Seminiferous tubules

Epididymis

Correct answer:

Seminiferous tubules

Explanation:

Spermatogenesis—the formation of spermatozoa—occurs in the seminiferous tubules of the testes. Seminiferous tubules are composed of Sertoli cells and spermatogenic cells. There is a high concentration of testosterone present in these tubules. High testosterone concentrations support sperm development. The epididymis is the site of sperm maturation. Last, the seminal vesicles are small glands that produce the majority of the seminal fluid. 

Example Question #292 : Systems Physiology

Which of the following is not one of the ways that Sertoli cells promote sperm maturation?

Possible Answers:

Contributing to testicular fluid

Riding the sperm of excess cytoplasm through phagocytosis

Protecting sperm from the immune system

Secreting testosterone

Correct answer:

Secreting testosterone

Explanation:

Sertoli cells are located in the seminiferous tubules and aid in spermiogenesis. There are many ways that Sertoli cells facilitate the process of sperm maturation including the following: the contribution of testicular fluid, phagocytosis of excess cytoplasm, and the protection of sperm from the immune system. Leydig cells—interstitial cells—are responsible for secretion of testosterone.

Example Question #293 : Systems Physiology

Which of the following is not a true characteristic of the oogonia?

Possible Answers:

They are diploid

They are produced in a process called oocytogenesis

The production of oogonia continues throughout the life of the individual 

They are formed prior to birth

Correct answer:

The production of oogonia continues throughout the life of the individual 

Explanation:

Oogonia are diploid germ line cells that are precursor ova cells. They are produced during a process called oocytogenesis before and sometimes shortly after birth; there are believed to be a finite number of oogonia in each female at the time of birth.

Example Question #294 : Systems Physiology

During which of the following stages of meiosis are primary oocytes' growth arrested in prior to the onset of puberty?

Possible Answers:

Prophase I

Prophase II

Metaphase I

Metaphase II

Correct answer:

Prophase I

Explanation:

Primary oocytes are diploid germ line cells that form from oogonia. Primary oocytes are immature ova. In order to develop further, primary oocytes enter into ootidogenesis, or meiosis to produce secondary oocytes. This process is arrested at prophase I late in fetal development. The period of arrest during ootidogenesis is called the dictyate stage and is characterized by a lack of cellular translation. This arrest is caused by blocked mRNA binding sites, which prevents translation initiation factors from binding. The dictyate stage ends before puberty by an increase in the secretion of luteinizing hormone (LH). 

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