Question

highlight key words in the information below:

• most enzymes are globular proteins - precise 3d shape.
• biological catalysts - increase the rate of metabolic reactions without being permanently changed.
• catalyse anabolic reactions (joining small molecules to make a larger one) as well as catabolic reactions (breaking down molecules).
• can be reused again and again - a small amount can catalyse a large volume of substrate.
• act by lowering the activation energy.
• have an active site - precise 3d shape.
• each enzyme usually only catalyses one reaction or one group of similar reactions - specificity (due to precise shape of active site).
• when substrate binds to enzyme to form the enzyme - substrate complex it causes a slight change in the shape of the enzyme = lock and key hypothesis and induced fit.
• the product is formed and released.
• name ends in -ase usually e.g. proteases break down protein molecules.
• can be totally made of protein or contain non - protein parts. if non - protein part is permanent it is called a prosthetic group. if it can be detached it is a coenzyme.

substrate
what is meant by the term catalyst?
a catalyst is a substance that increases the rate of a metabolic reaction without being permanently changed.
what is meant by the activation energy of an enzyme and how does the presence of an enzyme affect it

Explanation:

Step1: Identify key - words

These are important terms related to enzymes.

Step2: Define catalyst

Based on the given information.

Step3: Define activation energy and enzyme's effect

Using knowledge of enzyme - catalyzed reactions.

Answer:

1. Highlighted key - words: globular proteins, metabolic reactions, anabolic reactions, catabolic reactions, re - used, lowering the activation energy, active site, specificity, substrate, enzyme - substrate complex, lock and key hypothesis, induced fit, product, prosthetic group, coenzyme
2. Answer to "What is meant by the term catalyst?": A catalyst is a substance that increases the rate of a metabolic reaction without being permanently changed.
3. Answer to "What is meant by the activation energy of an enzyme and how does the presence of an enzyme affect it?": Activation energy is the minimum amount of energy required for a reaction to occur. The presence of an enzyme lowers the activation energy, thus increasing the rate of the reaction.