Question

enzymes

1. what is a catalyst?
2. proteins that act as biological catalysts are called
3. what do enzymes do?
4. from what is part of an enzyme’s name usually derived?

enzyme action

1. the reactants of enzyme - catalyzed reactions are known as
2. why are the active site and the substrates in an enzyme - catalyzed reaction often compared to a lock and key?
3. the binding together of an enzyme and a substrate forms a(an)
4. how do most cells regulate the activity of enzymes?

Explanation:

1. A catalyst is a substance that speeds up a chemical reaction without being consumed in the reaction.
2. Proteins that act as biological catalysts are called enzymes.
3. Enzymes speed up (catalyze) biological reactions by lowering the activation - energy required for the reaction to occur.
4. Part of an enzyme's name is usually derived from its substrate (the reactant it acts upon).
5. The reactants of enzyme - catalyzed reactions are known as substrates.
6. The active site and the substrates in an enzyme - catalyzed reaction are often compared to a lock and key because the active site has a specific shape that only certain substrates can fit into, similar to how a key has a specific shape for a particular lock.
7. The binding together of an enzyme and a substrate forms an enzyme - substrate complex.
8. Most cells regulate the activity of enzymes through feedback inhibition (where the end - product of a metabolic pathway inhibits an earlier enzyme in the pathway), allosteric regulation (binding of a molecule at a site other than the active site to change the enzyme's activity), and covalent modification (adding or removing chemical groups to/from the enzyme).

Answer:

1. A substance that speeds up a chemical reaction without being consumed.
2. Enzymes.
3. Speed up biological reactions by lowering activation - energy.
4. Its substrate.
5. Substrates.
6. Because the active site has a specific shape that only certain substrates can fit into.
7. Enzyme - substrate complex.
8. Through feedback inhibition, allosteric regulation, and covalent modification.