Question

Compare and contrast the differences between mature human eggs and sperm in the following questions. For each prompt, determine whether the property describes just eggs, just sperm, both types of gametes, or neither type. Select all answer choices that apply. They contribute nearly all of the cytoplasm to the offspring.
Human Eggs Human Sperm
Gamete Property
a. They undergo unequal cytoplasmic division during meiosis.
b. Their chromosomes have undergone genetic recombination and independent assortment.
c. They contain specialized secretory vesicles called cortical granules just under the plasma membrane.
d. They are characterized by a flagellum. Most of these gametes die without ever completing meiosis.
e. The acrosomal reaction occurs in these cells.
f. They can be derived from any adult cell type.
g. Unlike humans, aquatic organisms such as sea urchins practice external fertilization.
h. Sea urchins are often used for studying the cellular basis of sex, because the structure and behavior of their gametes can be much more easily observed than those of human gametes.
i. However, several key differences exist between animals that practice external fertilization and those, including humans, that practice internal fertilization.
Which of the following statements describe sea urchin reproduction but not human reproduction?
a. Fertilization is almost immediately followed by a strong depolarization of the egg plasma membrane, preventing additional sperm from fusing with the egg.
b. The egg is surrounded by a vitelline coat and a thick outer jelly layer.
c. The egg is surrounded by a mineralized shell added before the egg exits the body.

Answer 1

Answer:

QUESTION 1:

a. They undergo unequal cytoplasmic division during meiosis- eggs

b. Their chromosomes have undergone genetic recombination and independent assortment- both gamete types

c. They contain specialized secretory vesicles called cortical granules just under the plasma membrane- eggs

d. They are characterized by a flagellum. Most of these gametes die without ever completing meiosis- sperm

e. The acrosomal reaction occurs in these cells- sperm

f. They can be derived from any adult cell type- neither gametes

QUESTION 2:

c) The egg is surrounded by a mineralized shell added before the egg exits the body.

Explanation:

a) Female reproductive cells undergo meiosis to produce one large egg and three polar bodies. However, an unequal cytoplasmic division occurs in favour of the large egg.

b) Since both egg cell and sperm cell are produced via meiosis and meiotic division involves the processes of genetic recombination and independent assortment, hence, both gamete types have their chromosomes underg genetic recombination and independent assortment.

c) Egg cells contain specialized secretory vesicles called cortical granules just under the plasma membrane. This cortical granules help prevent more sperms from fertilizing the same egg after it has been fertilized.

d) Sperm cells possess flagellum for motility in the female reproductive tract. Most of the sperm cells die without ever completing meiosis.

e) Sperm cells possess an head-covering structure called ACROSOME. Acrosome reaction is the process undergone by sperm cells permeate the zona pellucida of the egg.

f) Gametes are specifically derived from adult reproductive cells and hence, NEITHER TYPE OF GAMETE can be derived from any adult cell type

QUESTION 2:

The egg in Sea urchins is surrounded by a mineralized shell added before the egg exits the body to the external environment. This does not occur in the humans because the egg does not leave the body but fertilized internally.