Biology Flashcards
7 cards from real OAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Biology flashcards as text
Which blood vessel type has the thinnest walls, facilitating gas and nutrient exchange?
Answer: Capillaries
Capillaries have walls only one cell thick (endothelium), allowing efficient diffusion of gases and nutrients.
The process by which a cell engulfs large solid particles is called:
Answer: Phagocytosis
Phagocytosis ('cell eating') involves pseudopod extension to engulf large particles such as bacteria or debris.
Which nitrogenous base is found in RNA but NOT in DNA?
Answer: Uracil
RNA contains uracil in place of the thymine found in DNA; uracil pairs with adenine.
In the human excretory system, the loop of Henle is critical for:
Answer: Creating a concentration gradient in the medulla
The loop of Henle establishes an osmotic gradient in the renal medulla that allows the collecting duct to concentrate urine.
Which of the following best describes an exergonic reaction?
Answer: Releases net free energy and is thermodynamically spontaneous
Exergonic reactions have a negative ΔG, meaning they release free energy and occur spontaneously.
Sensory neurons that carry impulses FROM sensory receptors TO the central nervous system are called:
Answer: Afferent neurons
Afferent (sensory) neurons transmit signals from receptors toward the CNS; efferent neurons carry signals away.
Which phase of the cell cycle involves DNA replication?
Answer: S phase
DNA replication occurs during the S (synthesis) phase of interphase, doubling the cell's genetic material.