Question 1

Which of the following best describes the process and significance of capacitation in sperm during fertilization?

Accepted Answer

Capacitation is the functional maturation of sperm within the female reproductive tract, enabling them to penetrate and fertilize the oocyte.

Question 2

A couple is undergoing in vitro fertilization (IVF). Which step most closely mimics the natural process of cleavage in early embryonic development?

Accepted Answer

The rapid mitotic divisions of the zygote without intervening growth, resulting in a blastocyst.

Question 3

Which hormone is primarily responsible for maintaining the corpus luteum and preventing menstruation during the early stages of pregnancy?

Accepted Answer

Human chorionic gonadotropin (hCG)

Question 4

A newborn fails to take its first breath after birth. Which physiological mechanism is most likely impaired?

Accepted Answer

Accumulation of carbon dioxide in the blood, triggering the respiratory centers in the brain.

Question 5

Which extraembryonic membrane is correctly matched with its primary function?

Accepted Answer

Yolk sac – source of early blood cells

Question 6

A genetic disorder is inherited in an X-linked recessive pattern. Which of the following statements is most accurate?

Accepted Answer

Males express the disorder if they inherit one copy of the mutant allele from their mother.

Question 7

Which event marks the completion of implantation during early pregnancy?

Accepted Answer

The blastocyst is entirely surrounded by endometrial tissue.

Question 8

A patient with cystic fibrosis is found to be homozygous for a recessive allele. What is the probability that two carrier parents (heterozygotes) will have a child with cystic fibrosis? Use the Punnett square and the laws of probability.

Accepted Answer

$$\displaystyle \frac{1}{4}$$

Question 9

Which of the following best explains why mitochondrial disorders are inherited only from the mother?

Accepted Answer

Mitochondria in the zygote are derived from the ovum, as sperm mitochondria are typically destroyed after fertilization.

Question 10

A woman is 10 weeks pregnant and wishes to have early genetic testing for chromosomal abnormalities. Which procedure is most appropriate and why?

Accepted Answer

Chorionic villus sampling, because it can be performed at 10 weeks and allows rapid karyotyping.

Question 11

Which of the following is a direct result of the positive feedback loop involving oxytocin during labor?

Accepted Answer

Increased uterine contractions leading to delivery of the infant

Question 12

A child is born with a phenotype intermediate between those of both parents for a particular trait. Which inheritance pattern does this most likely represent?

Accepted Answer

Incomplete dominance

Question 13

Which of the following best describes the role of methylation in gene expression?

Accepted Answer

Methylation generally prevents DNA transcription by condensing chromatin.

Question 14

A patient with Huntington’s disease has a parent who is heterozygous for the disease allele. What is the probability that the patient inherited the disease allele, assuming the other parent is homozygous normal? Use the laws of probability.

Accepted Answer

$$\displaystyle \frac{1}{2}$$

Question 15

Which of the following best explains why polygenic traits, such as height, show a continuous range of phenotypes?

Accepted Answer

They are influenced by multiple gene pairs, each contributing to the phenotype.

Question 16

A newborn is unable to produce surfactant in the lungs. Which physiological consequence is most likely?

Accepted Answer

Increased surface tension in the alveoli, making breathing difficult

Question 17

Which of the following best describes the function of the ductus arteriosus in fetal circulation?

Accepted Answer

It shunts blood from the pulmonary trunk to the aorta, bypassing the fetal lungs.

Question 18

Which of the following is a real-life example of a phenocopy?

Accepted Answer

A child with mental retardation due to maternal alcohol consumption during pregnancy

Question 19

Which of the following best explains why carriers of a recessive genetic disorder do not express the disorder?

Accepted Answer

They have one normal allele that produces enough functional protein to prevent the disorder.

Question 20

Which process during meiosis is primarily responsible for generating new combinations of alleles on the same chromosome?

Accepted Answer

Crossing over

Pregnancy, Human Development, and Heredity: Study Notes

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