AP Biology : Systems Physiology

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #2 : Understanding Internal Anatomy

What term refers to the finger-like folds that line the fallopian tubes?

Possible Answers:

Flagella

Villi

Fimbriae

Microtubules

Endoderm

Correct answer:

Fimbriae

Explanation:

In female mammals, the fimbriae are finger-like projections that sweep the ovulated egg from the ovary into the oviduct.

Villi are found in the digestive tract and work to increase surface area for more efficient absorption of nutrients. Flagella are threadlike structures that provide motility for sperm. Microtubules are composed of the protein tubulin, and are used in the construction of cilia and flagella. The endoderm is the innermost embryonic tissue layer, which develops to form the lining of the respiratory and digestive tracts. 

Example Question #1 : Reproductive Anatomy

Men and women are composed of the same cells, though distributed differently. Based on their cell composition, the  _____ in boys is akin to the clitoris in girls.

Possible Answers:

testicles

urethra

perineum

shaft

glans

Correct answer:

glans

Explanation:

The glans is the correct answer here. It is composes of the same types of cells as the clitoris.

Example Question #1 : Understanding Embryogenesis And Development

During embryonic development, which stage begins after the formation of 128 cells and terminates with germ layer differentiation? 

Possible Answers:

Gastrula stage

Blastula stage

Zygote stage

Cleavage stage

Somitogenesis stage

Correct answer:

Blastula stage

Explanation:

The blastula is defined as beginning following the cleavage stages. Following seven cleavages 128 cells have formed, and will later begin to form the differentiated layers of endoderm, mesoderm and ectoderm before going into the gastrula stage.

Example Question #2 : Understanding Embryogenesis And Development

From what germ layer does the nervous system develop?

Possible Answers:

Somites

Endoderm

Ectoderm

Mesoderm

Epiboly

Correct answer:

Ectoderm

Explanation:

During gastrulation, the ectoderm begins to fold in on itself following the primitive streak. These neural folds form the basis of the neural tube, later developing into the adult nervous system.

Example Question #1 : Reproductive Physiology

What do somites, formed from mesoderm during somitogenesis, go on to form? 

Possible Answers:

Skeletal muscle

All of these structures

The dermis

Vertebrae

None of these structures

Correct answer:

All of these structures

Explanation:

Somites go on to form skeletal muscle, vertebrae, and the dermis. 

Example Question #4 : Reproductive Physiology

In humans, fertilization involves the addition of chromosomes from the sperm and the egg. The resulting cell is called a __________.

Possible Answers:

embryo

gamete

zygote

blastocyst

Correct answer:

zygote

Explanation:

The fusion of haploid gametes (sperm and egg) produces a zygote. The addition of the chromosomes from sperm and egg restores the diploid state of the cell and gives rise to a diploid organism.

An embryo refers to the developing organism after the first cellular division, following formation of the zygote. A blastocyst forms during the first stages of embryogenesis, and is defined by cellular replication without cellular growth.

Example Question #1 : Reproductive Physiology

What is the product of rapid division, but no overall growth during embryogenesis?

Possible Answers:

Zygote

Blastula

Gastrula

Morula

Correct answer:

Morula

Explanation:

The first stage after fertilization is the single-celled zygote, which quickly begins to divide. These divisions, however, do not increase the overall size of the embryo and are known as cleavage divisions. As the mass of cells divides, it is considered a morula.

Eventually, the morula develops an inner cell mass and associated trophoblast. At this stage, it is considered a blastula or blastocyst. It is during this stage that implantation occurs. After implantation, the cell develops the three germ layers through the process of gastrulation. Once the endoderm, mesoderm, and ectoderm have been established, the embryo is considered a gastrula.

Example Question #3 : Understanding Embryogenesis And Development

Which body part would you not expect to develop from the ectoderm?

Possible Answers:

The cerebellum

The eyes

The skin

The intestinal lining

The spinal cord

Correct answer:

The intestinal lining

Explanation:

The ectoderm is generally credited with the formation of the skin, teeth, nervous system, and sense organs. The lining of the digestive tract is formed from the endoderm.

Example Question #4 : Understanding Embryogenesis And Development

Which of the following would not be expected during pregnancy?

Possible Answers:

Formation of the corpus albicans

Blastocyst implantation

Formation of the placenta

Maintenance of the corpus luteum

Secretion of human chorionic gonadotropin (HCG)

Correct answer:

Formation of the corpus albicans

Explanation:

The corpus luteum is a structure in the ovary that secretes progesterone, and is preserved during pregnancy with the help of human chorionic gonadotropin (HCG). If fertilization does not take place, the corpus luteum will degenerate into the corpus albicans. As a result, corpus albicans formation only takes place if the woman is not pregnant.

Blastocyst implantation is considered the first event of pregnancy, and the placenta will later form in order to secrete hormones crucial for embryonic development.

Example Question #5 : Reproductive Physiology

Early in development, the zygote divides via __________.

Possible Answers:

cloning

meiosis

mitosis

fertilization

Correct answer:

mitosis

Explanation:

Mitosis is the process by which diploid cells duplicate and divide to ensure all cells have the same number of chromosomes and genetic material. Meiosis is the process by which haploid gametes are produced by the primary sex organs.  

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