AP Biology : Systems Physiology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #61 : Reproductive System

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

Possible Answers:

Removes excess cytoplasm

Aids in the development of sperm motility

Aids in axoneme formation

Removes excess organelles

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 #13 : Understanding Gametogenesis

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:

It places the testes outside of the body

Spermatozoa are immotile in the seminiferous tubules

It reduces catalytic activity 

Hormones lower the temperature in the testes

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 #14 : Understanding Gametogenesis

Where does the process of spermatogenesis occur in humans?

Possible Answers:

Seminal vesicle

Ejaculatory duct

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 #15 : Understanding Gametogenesis

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

Possible Answers:

Protecting sperm from the immune system

Contributing to testicular fluid

Riding the sperm of excess cytoplasm through phagocytosis

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 #11 : Understanding Gametogenesis

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

Possible Answers:

They are produced in a process called oocytogenesis

The production of oogonia continues throughout the life of the individual 

They are diploid

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 #12 : Understanding Gametogenesis

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

Possible Answers:

Metaphase II

Prophase II

Prophase I

Metaphase I

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). 

Example Question #1261 : Ap Biology

When is the process of ootidogenesis completed?

Possible Answers:

At the time of fertilization 

At birth

At the time of ovulation 

Just before the onset of puberty 

Correct answer:

At the time of fertilization 

Explanation:

Ootidogenesis is the production of secondary ooctyes from primary ooctyes through meiosis. Ootidogenesis features two periods of developmental arrest—dictyate—during the prophase I stage of meiosis I and during metaphase II of meiosis II. The dictyate stage of arrest ends at the onset of puberty due to a spike in luteinizing hormone (LH) levels. Ootidogenesis then continues until the second arrest period during metaphase II. This period ends at fertilization and allows the completion of ootidogenesis.

Example Question #291 : Systems Physiology

Which of the following characteristics is true for secondary oocytes?

Possible Answers:

They are formed through mitosis

They are diploid

They are produced by a process called ootidogenesis

They arrest development prior to puberty 

Correct answer:

They are produced by a process called ootidogenesis

Explanation:

Secondary oocytes are haploid cells that are produced by primary oocytes through meiosis in a process called ootidogenesis. Secondary oocytes remain arrested in the metaphase II stage of meiosis until fertilization, when ootidogenesis is completed. The process of ootidogenesis also produces polar bodies.

Example Question #292 : Systems Physiology

Which of the following terms best describes the process of polar body formation?

Possible Answers:

Symmetrical cellular division

Asymmetrical cellular division

Apoptosis

Nondisjunction

Correct answer:

Asymmetrical cellular division

Explanation:

Polar bodies are haploid cells produced during ootidogenesis. They are smaller than secondary oocytes due to asymmetric cell division. During asymmetrical cell division a smaller volume of cytoplasm is partitioned into the polar bodies than to the secondary oocytes. This makes polar bodies not viable for fertilization. Polar bodies are often degraded, but they can also remain in the human body.

Example Question #292 : Systems Physiology

Where in the human body does oogenesis take place?

Possible Answers:

Fallopian tubes

Cervix

Ovaries

Uterus

Correct answer:

Ovaries

Explanation:

Oogenesis, or the formation of egg cells, takes place in the ovaries. Specifically, oogenesis takes place in the follicles—a pack of cells surrounding developing oocytes that is located within the ovaries.

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