A student observes that enzyme activity peaks at and declines rapidly above . What molecular mechanism causes this abrupt decline in activity at elevated temperatures?
Answer and explanation
Correct answer: A. Thermal denaturation disrupts tertiary protein structure and active site geometry
- Step 1: Enzymes are globular catalytic proteins whose activity depends on specific tertiary three-dimensional active-site conformation.
- Step 2: Excessive thermal energy breaks delicate non-covalent hydrogen bonds and hydrophobic interactions, denaturing the protein and destroying active-site catalytic function.
Answer
Thermal denaturation disrupts tertiary protein structure and active site geometry.
Why not the others: 'Runs out of activation energy' is a misunderstanding, as thermal energy increases; 'Substrate evaporates' is incorrect in liquid aqueous solution; 'Converts into a lipid' is chemically impossible.
Practise more Biological Systems and Scientific Inquiry.
Free questions with an explanation for every one, and full timed Egyptian STEM Schools Admissions Assessment mock tests.
More Biological Systems and Scientific Inquiry questions
- In a controlled scientific experiment designed to test the effect of nitrogen fertilizer concentration on tomato plant growth rate, which va…
- Which organelle in eukaryotic plant cells contains chlorophyll and carries out the light-dependent reactions of photosynthesis within its th…
- In a monohybrid Mendelian cross between two heterozygous tall pea plants (), what is the expected phenotypic ratio of tall to…
- During which phase of cellular mitosis do sister chromatids separate at their centromeres and migrate toward opposite spindle poles?
- What is the net yield of ATP molecules generated per molecule of glucose during anaerobic glycolysis in the cytoplasm?
- Which base is found in RNA molecules in place of the thymine () present in DNA?