Biology Quiz on Natural Selection and Enzymes

Which of the following scenarios best illustrates the principle of natural selection?

• A bear learning to hibernate during winter

• A giraffe with a longer neck reaching more food and having more offspring

• A bird migrating to a warmer climate during winter

• A lion hunting antelope in the wild

If an enzyme is denatured due to high temperature, which structural level is primarily affected?

• Primary

• Secondary

• Tertiary

• Quaternary

A student notices that plant B grew more rapidly under red light than blue light. What is the most reasonable conclusion?

• Blue light promotes more growth

• Red light inhibits chlorophyll production

• Plant B absorbs red light more efficiently for photosynthesis

• Light has no impact on plant growth

If a mutation causes an amino acid change in an enzyme's active site, what is the likely outcome?

• Increased temperature stability

• Reduced enzyme specificity

• Increased cell respiration

• Enhanced substrate binding

Why would a cell undergoing aerobic respiration produce more ATP than one relying on fermentation?

• Oxygen prevents ATP loss

• Fermentation consumes ATP

• Oxygen acts as the final electron acceptor, allowing full glucose breakdown

• Fermentation blocks glycolysis

What would happen to a freshwater protist if placed in saltwater?

• It would swell

• It would lyse

• It would lose water and shrink

• It would remain unaffected

If photosystem II is inhibited in a plant, what is the most immediate consequence?

• ATP production increases

• NADPH formation ceases

• Oxygen evolution is halted

• Calvin cycle accelerates

How would a non-functional tRNA affect protein synthesis?

• Inhibit transcription

• Misfold protein structures

• Disrupt codon-anticodon pairing, halting elongation

• Increase enzyme activity

What happens if a ribosome encounters a premature stop codon?

• Continues translation

• Produces a full-length protein

• Releases an incomplete polypeptide

• Changes the mRNA sequence

If the pH inside a lysosome becomes neutral, what is the most likely impact?

• Enzymes become more active

• Lysosome bursts

• Digestive enzymes become inactive

• Protein synthesis increases