GCSE Biology - What are Enzymes?

The video explains the role and importance of enzymes in biological processes. It covers how enzymes act as catalysts to speed up chemical reactions without being consumed. The structure of enzymes, composed of amino acids, allows them to have specific active sites that bind to substrates. The video also discusses two models of enzyme action: the lock and key model and the induced fit model, highlighting how enzymes change shape to fit substrates more effectively.

Why are enzymes crucial for the functioning of living cells?

• They decrease the temperature of reactions.

• They increase the speed of chemical reactions.

• They are used up in reactions.

• They provide energy for reactions.

What is a unique feature of enzymes that allows them to catalyze reactions repeatedly?

• They can only catalyze one reaction at a time.

• They remain unchanged after catalyzing a reaction.

• They require high temperatures to function.

• They are permanently altered after each reaction.

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

• It provides energy for the reaction.

• It binds to substrates to speed up reactions.

• It changes the enzyme's shape permanently.

• It releases products of the reaction.

How does the induced fit model differ from the lock and key model?

• The substrate changes shape to fit the enzyme.

• The enzyme changes shape to fit the substrate better.

• The substrate fits perfectly without any change.

• The enzyme and substrate do not interact.

Which analogy best describes the induced fit model?

• A shoe fitting into a shoebox.

• A puzzle piece fitting into a puzzle.

• A hand fitting into a rubber glove.

• A key fitting into a lock.