MTTC Biology Flashcards

Which process converts glucose into pyruvate during cellular respiration?

Answer: Glycolysis

Glycolysis occurs in the cytoplasm and converts one glucose molecule into two pyruvate molecules, yielding a net gain of 2 ATP.

A student observes that a plant placed near a window grows toward the light. This response is called:

Answer: Phototropism

Phototropism is the directional growth of a plant in response to light, mediated by unequal distribution of auxin.

Which type of RNA carries amino acids to the ribosome during translation?

Answer: tRNA

Transfer RNA (tRNA) carries specific amino acids to the ribosome and uses its anticodon to match codons on mRNA.

A population of beetles lives on light-colored bark. Over many generations, birds eat more dark beetles than light ones. This is an example of:

Answer: Directional selection

Directional selection favors one extreme phenotype (light color) over others, shifting the population's average trait in one direction.

Which organelle is primarily responsible for detoxifying harmful substances in liver cells?

Answer: Peroxisome

Peroxisomes contain enzymes like catalase that break down hydrogen peroxide and other toxic molecules in liver and kidney cells.

In an ecosystem, which trophic level has the greatest amount of energy available?

Answer: Producers

Producers (plants) occupy the base of the energy pyramid, capturing solar energy and containing the most total energy in the ecosystem.

A mutation that changes a codon from UAC to UAA would most likely result in:

Answer: Premature termination of translation

UAA is a stop codon; changing UAC (tyrosine) to UAA causes translation to terminate prematurely, producing a truncated protein.