CLEP Biology Organismal Biology & Physiology 3

Question 1

A plant in a desert environment has thick, waxy cuticles and sunken stomata. These adaptations primarily help the plant to:

Accepted Answer

Reduce water loss through transpiration

Answer

Thick waxy cuticles and sunken stomata reduce the water potential gradient and wind exposure, minimizing transpirational water loss in arid conditions.

Question 2

The sinoatrial (SA) node is often called the pacemaker of the heart because it:

Accepted Answer

Generates spontaneous electrical impulses that set heart rate

Answer

The SA node depolarizes spontaneously at a regular rhythm, initiating each heartbeat and determining the intrinsic heart rate.

Question 3

Which digestive enzyme is secreted by the pancreas and is responsible for breaking down starch in the small intestine?

Accepted Answer

Pancreatic amylase

Answer

Pancreatic amylase is released into the duodenum and hydrolyzes starch into maltose and shorter oligosaccharides.

Question 4

In vertebrates, the myelin sheath around axons is produced by which cells in the peripheral nervous system?

Accepted Answer

Schwann cells

Answer

Schwann cells wrap around peripheral nerve axons to form the myelin sheath, increasing the speed of action potential conduction.

Question 5

Which event triggers ovulation in the human female menstrual cycle?

Accepted Answer

A surge in luteinizing hormone (LH)

Answer

The mid-cycle LH surge triggers the release of a secondary oocyte from the dominant follicle, an event called ovulation.

CLEP Practice Test

CLEP Practice Test

CLEP Biology Organismal Biology & Physiology 3