Question 1

Which of the following best describes the process of capacitation in sperm prior to fertilization?

Accepted Answer

It is the process by which the sperm's membrane becomes more permeable and the sperm becomes able to sense and swim toward chemicals released by the oocyte.

Question 2

Which mechanism prevents polyspermy in human fertilization?

Accepted Answer

The cortical reaction, which hardens the zona pellucida and destroys sperm receptors.

Question 3

A couple has fraternal (dizygotic) twins. Which of the following is TRUE about their development?

Accepted Answer

Each twin develops from a separate oocyte fertilized by a different sperm and has its own placenta.

Question 4

Which extraembryonic membrane is primarily responsible for absorbing shock and later contains urine and sloughed cells from the fetus?

Accepted Answer

Amnion

Question 5

A genetic disorder is inherited in an autosomal recessive manner. If both parents are heterozygous carriers, what is the probability that their child will express the disorder?

Accepted Answer

$\frac{1}{4}$

Question 6

Which of the following best describes the role of the trophoblast during implantation?

Accepted Answer

It secretes enzymes that allow the embryo to burrow into the endometrium and utilize maternal nutrients.

Question 7

Which primary germ layer gives rise to the nervous system and epidermis?

Accepted Answer

Ectoderm

Question 8

A male child is born with red-green color blindness, an X-linked trait. Which of the following must be TRUE about his parents?

Accepted Answer

His mother must be a carrier or color blind.

Question 9

Which of the following is a correct statement about the placenta?

Accepted Answer

It functions in the transfer of nutrients and wastes between mother and fetus and secretes estrogens and progesterone.

Question 10

Which of the following best explains why polyspermy is lethal in humans?

Accepted Answer

It leads to an excess of genetic material, resulting in a nonviable cell.

Question 11

Which of the following is TRUE regarding the inheritance of sickle-cell trait?

Accepted Answer

Individuals with genotype $Ss$ produce both normal and abnormal hemoglobin.

Question 12

Which of the following best describes the genotype and phenotype relationship for phenylketonuria (PKU)?

Accepted Answer

Individuals with genotype $Pp$ are carriers and produce the enzyme.

Question 13

Which of the following is an example of multiple allele inheritance?

Accepted Answer

Blood groups (A, B, O)

Question 14

A blastocyst consists of which of the following components?

Accepted Answer

Trophoblast, embryoblast (inner cell mass), and blastocyst cavity

Question 15

Which extraembryonic membrane eventually becomes part of the umbilical cord and later forms the urinary bladder?

Accepted Answer

Allantois

Question 16

Which of the following best describes the process of gastrulation?

Accepted Answer

The differentiation and arrangement of the embryoblast into three primary germ layers.

Question 17

A woman undergoes amniocentesis during pregnancy. What is the primary purpose of this procedure?

Accepted Answer

To check for genetic disorders in the fetus.

Question 18

Which of the following statements about monozygotic (identical) twins is correct?

Accepted Answer

They originate from a single fertilized oocyte that splits into two embryos.

Question 19

Which germ layer forms the epithelial lining of the digestive, respiratory, and urinary systems?

Accepted Answer

Endoderm

Question 20

A male child is born with hemophilia, a sex-linked disorder. Which of the following is most likely TRUE?

Accepted Answer

His mother is a carrier or affected by hemophilia.

Human Development and Heredity: Fertilization, Embryogenesis, and Genetic Inheritance

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