The Role Of Enzymes In Biochemical Reactions And Their Mechanisms

Enzymes are proteins or RNA that accelerate biochemical reactions by lowering activation energy. Discovered by Anselme Payen, enzymes are specific to substrates and have active sites where reactions occur. They may require cofactors to function. Models like Lock and Key and Induced Fit explain enzyme action. Environmental factors such as temperature, pH, and concentrations affect enzyme activity. Inhibitors can block or alter enzyme function, with competitive and non-competitive types.

Who was the first to discover enzymes and what role do they play in biochemical reactions?

• Albert Einstein; they initiate reactions

• Marie Curie; they stop reactions

• Louis Pasteur; they slow down reactions

• Anselme Payen; they speed up reactions

How do enzymes speed up chemical reactions?

• By changing the pH

• By lowering the activation energy

• By increasing substrate concentration

• By increasing the temperature

What is the role of the active site in an enzyme?

• It binds to substrates for reactions

• It binds to inhibitors

• It increases the enzyme's temperature

• It changes the enzyme's shape

What is a holoenzyme composed of?

• Active site and substrate

• Cofactor and substrate

• Substrate and inhibitor

• Apoenzyme and coenzyme

Which model suggests that the enzyme changes shape to fit the substrate more tightly?

• Lock and Key Hypothesis

• Induced Fit Hypothesis

• Enzyme-Substrate Complex

• Substrate Model

What happens to enzymes at temperatures higher than 37°C?

• They become acidic

• They become more active

• They denature

• They change color

How does pH affect enzyme activity?

• It only affects enzymes at high temperatures

• It can denature enzymes at extreme values

• It makes enzymes more basic

• It has no effect

What is the effect of increasing enzyme concentration on the rate of reaction?

• It decreases the rate

• It stops the reaction

• It has no effect

• It increases the rate up to a point

What do competitive inhibitors do to enzyme activity?

• They bind to the substrate

• They increase enzyme activity

• They occupy the active site

• They change the enzyme's shape

How do non-competitive inhibitors affect enzymes?

• They bind to the active site

• They attach elsewhere and distort enzyme shape

• They increase substrate concentration

• They lower the activation energy