SAT - Biology Subject Human Anatomy and Physiology Questions and Answers

Question 1

Which of the following describes the primary role of calcium ions (Ca2+) in the contraction of a skeletal muscle fiber?

Accepted Answer

To bind to troponin, which causes tropomyosin to shift and expose the myosin-binding sites on actin.

Answer

To bind to the myosin heads, activating them for the power stroke.

Answer

To generate the action potential that propagates along the sarcolemma.

Answer

To provide the energy for the detachment of the myosin head from the actin filament.

Question 2

A patient is found to have a consistently high level of blood calcium (hypercalcemia). A defect in which of the following glands or hormones would most likely contribute to this condition through a failure of negative feedback?

Accepted Answer

Overproduction of parathyroid hormone (PTH) by the parathyroid glands.

Answer

Overproduction of calcitonin by the thyroid gland.

Answer

Underproduction of parathyroid hormone (PTH) by the parathyroid glands.

Answer

Overproduction of insulin by the pancreas.

Question 3

Which of the following correctly traces the path of deoxygenated blood as it enters the heart and is pumped toward the lungs?

Accepted Answer

Superior Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery

Answer

Left Atrium → Left Ventricle → Aorta

Answer

Pulmonary Vein → Left Atrium → Left Ventricle → Pulmonary Artery

Answer

Right Ventricle → Right Atrium → Superior Vena Cava → Lungs

Question 4

The primary function of the Loop of Henle within the nephron of the kidney is to:

Accepted Answer

create a salt concentration gradient in the renal medulla.

Answer

filter large proteins and blood cells out of the blood plasma.

Answer

secrete waste products like urea and ammonia into the filtrate.

Answer

reabsorb all glucose and amino acids from the filtrate.

Question 5

During the transmission of a nerve impulse, the rapid depolarization of the neuron's membrane is primarily caused by which event?

Accepted Answer

The influx of sodium ions (Na+).

Answer

The influx of potassium ions (K+).

Answer

The efflux of sodium ions (Na+).

Answer

The efflux of chloride ions (Cl-).

Question 6

In the human respiratory system, the exchange of oxygen and carbon dioxide between the air and the blood occurs across the walls of the alveoli and capillaries. By which physical process does this gas exchange primarily occur?

Accepted Answer

Simple Diffusion

Answer

Active Transport

Answer

Osmosis

Answer

Facilitated Diffusion