MCAT Biology : Regulation of Developmental Processes

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #1 : Regulation Of Developmental Processes

In all vertebrates, when the optic cup does not develop in the embryo the lens also does not develop either. This provides evidence for which of the following statements?

Possible Answers:

The process of neurulation follows gastrulation

Cell differentiation is an all-or-nothing phenomenon

Cells may induce neighboring cells to differentiate

The eye develops early in vertebrate morphogenesis

Correct answer:

Cells may induce neighboring cells to differentiate

Explanation:

The failure of the lens to form in the absence of the optic cup indicates that the optic cup is necessary for lens development, and may in fact induce it.

This fact says nothing in regards to the timing of neurulation, nor the timing of eye development. Finally, cell differentiation is a gradual process, not all-or-nothing, and the statement is irrelevant to the development of the optic cup and lens.

Example Question #2 : Regulation Of Developmental Processes

What is the function of anti-Müllerian hormone (AMH)?

Possible Answers:

Female-to-male sexual differentiation in the fetus

Negative feedback to inhibit menstrual cycle

Maternal satiation hormone

Positive feedback to promote fetal growth hormones

Erythropoiesis in the fetus

Correct answer:

Female-to-male sexual differentiation in the fetus

Explanation:

Anti-Mullerian hormone is present only in male fetuses. It is responsible for the degeneration of the Mullerian ducts, which form the oviducts, uterus, and upper vagina in females.

Example Question #3 : Regulation Of Developmental Processes

A deficiency of calcium in the diet can result in which of the following conditions?

Possible Answers:

Two of these answers

Osteoporosis

Increased blood-oxygen carrying capacity

Muscle spasms

Reduced blood-oxygen carrying capacity

Correct answer:

Two of these answers

Explanation:

Osteoporosis is a disease that causes a decrease in bone mass and density and can be induced by malnutrition or calcium deficiency. Even if the disease appears unfamiliar, the prefix "osteo-" indicates a relationship to bone, which is closely linked to calcium levels int he body.

Calcium is also an important ion involved in neural action potentials; it is responsible for triggering the release of neurotransmitters into the synaptic cleft. A calcium deficiency may cause improper action potentials that result in spasms.

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