Question

1. If a genetic mutation caused seminal fluid to coagulate more quickly, what would be a likely effect for the male reproductive system?

A. The epididymis would not be able to store sperm.

B. Delivery of semen and viability of sperm would be affected.

C. The vas deferens would become blocked with semen.

D. Sperm production could no longer take place in the testes, but would still occur in the scrotum.

2. Which of the following correctly explains how gene expression can change in a differentiating cell in an animal embryo?

A. DNA methylation triggered by apoptosis leads to suppression of some genes and expression of others.

B. Presence of germ layers trigger hormonal release from endocrine glands, signaling to certain cells to express genes.

C. Cell signals through plasmodesmata allow coordination of cellular activities and cell differentiation.

D. Cues from the cytoplasm and from surrounding cells can induce changes in gene expression.

3. Which of the following is NOT an example of cell migration as a part of cell differentiation?

A. mesenchyme cells forming mesoderm during gastrulation

B. primitive streak formation in a chick embryo

C. concentration of protein complexes during cleavage

D. convergent extension to elongate the archenteron in the sea urchin

4. Describe the steps from ovulation through implantation in the uterine wall. How does hormonal control of these steps occur?

Answer 1

Answer :

1)

Correct choice is B

Seminal fluid is formed in seminal vesicle. Sperm comes from epididymis and vas deferens before joining seminal vesicle. The liquifaction time of semen is very important in viability of sperm.

2)

Correct choice is A

Apoptosis can induce DNA methylation.

By DNA methylation the gene expression decreases.

Plasmodesmata is interconnected cytoplasm of 2 cells.

3)

Correct choice is C

In mesenchymal cells forming mesoderm there is cell migration.

In primitive streak formation of chick embryo also there is cell migration.

In sea urchin convergent extension of archenteron is part of gastrulation which involves cell migration.

4)

• The released ovum from ovary.
• Ovum is captured by fimbriae of fallopian tube.
• Ovum moves through fallopian tube.
• It can remain viable for 12 to 24 hours.
• In that time if sperm enters by insemination sperm and egg fuses in fallopian tube.
• Zygote is formed.
• By cell division blastocyst forms
• It moves to uterus through cornua.
• There it gets implanted in uterine wall in the endometrium

During ovulation LH increases. LH surge results in ovulation.

Then corpus luteum secrete progesterone which is very important for implantation and continuation of pregnancy. Beta hcg is also very important in continuation of pregnancy. Estrogen also is important.