ib bio1 enzymes

C1.1 Interaction & Interdependence in Molecules

LEARNING OUTCOMES

1. Enzymes as catalysts

2. Role of enzymes in metabolism

3. Anabolic and catabolic reactions

4. Enzymes as globular proteins with an active site for catalysis

Multiple Choice

An enzyme is a

• carbohydrate.

• protein.

• lipid.

• nucleic acid.

Multiple Choice

The region on the surface of the enzyme that the substrate binds to is the

• active site.

• activation energy.

• lock-and-key model.

• catalysis.

​Enzymes

• Globular proteins that act as biological catalysts that increase the rate of metabolic reactions
  

Multiple Choice

The complex network of interdependent and interacting chemical reactions occuring in living organisms is known as

• metabolism

• anabolic reactions

• catabolic reactions

• specificity

Multiple Choice

Catabolic reactions...

• ...build up smaller molecules into larger ones.

• ...break down larger molecules into smaller ones.

Multiple Choice

Condensation of monomers into macromolecules is a(n) ________ reaction

• anabolic

• catabolic

​LOCK AND KEY MODEL

-portrays an enzyme as conformationally rigid and able to bond only to substrates that exactly fit the active site.

​INDUCED FIT MODEL

-enzyme structure as more flexible and is complementary to the substrate only after the substrate is bound

Multiple Choice

As a substrate approaches an active site, the substrate and enzyme both slightly change shape, known as

• concentration increase

• lock and key

• induced fit

• enzyme substrate specificity

Multiple Choice

According to the induced fit model, as a substrate approaches an enzyme, it induces a ______________ in both the substrate and the active site.

• conformational change

• chemical change

• color change

Multiple Choice

Enzymes act as catalysts to __________ the rate of a biochemical reaction by ___________ the activation energy needed for the reaction to occur.

• increase, lowering

• decrease, lowering

• increase, raising

• decrease, raising

Multiple Choice

After an enzyme is denatured, the substrate can ______ to the active site.

• bind

• no longer bind

Multiple Choice

At temperatures above the optimum temperature, enzyme stability will _______.

• decrease

• increase

Multiple Choice

The graph for substrate concentration vs enzyme activity begins to flatten out because

• all active sites are full and the enzymes are working at their maximum efficiency.

• the enzymes are used up and there aren't any left.

Multiple Choice

T/F: All enzymes have the same optimum pH range.

• true

• false