Ch.5 Metabolism enzymes

Enzymes are not used up nor permanently altered and may be reused over and over

Are enzymes permanently changed when they interact with their substrate?

Enzymes are "substrate specific", they bind to specific molecules only

Are enzymes specific for their substrate?

When it is too high or too low the protein denatures

How does pH affect enzyme activity?

With increasing concentration of substrate molecules, the rate of reaction increases until the active sites on all the enzyme molecules are lifted, at which point the maximum rate of reaction is reached.

How does substrate concentration affect enzyme activity?

The enzymatic activity (rate of reaction catalyzed by the enzyme) increases with increasing temperature until the enzyme, a protein, is denatured by heat and inactivated. At this point, the reaction rate falls steeply.

If an enzyme is heated so it loses its tertiary structure (denatured), will it still catalyze a chemical reaction? Explain.

10 enzymes

In a metabolic pathway involving 10 different steps, how many enzymes will be required?

NAD+, FAD. These electrons play a role in ATP synthesis.

Name two coenzymes that act as hydrogen atom/electron carriers. What is their role in glycolysis and aerobic respiration?

Catalysts speed up chemical reactions by lowering the activation energy.

What are catalysts?

Organic cofactors= coenzymes. They are made of organic molecules and assist enzymes to carry out their function. They help with the specificity of the binding site. Usually helps electron rearrangement.

What are coenzymes?

Nonprotein component of an enzyme

What are cofactors?

RNA catalysts. Ribosomal ribozymes catalyze formation of peptide bonds in proteins. 1st primitive organic catalysts

What are ribozymes?

Enzymes have a substrate binding site called the "active site" which determines substrate specificity

What determines the substrate specificity?

That it is an enzyme

What does the suffix "-ase" tell us?

The substance the enzyme binds and "changes"

What is a substrate?

Energy required to start chemical reactions

What is activation energy?

The enzyme is working as fast as it can and you can add as much substrate as you want and that enzyme cannot work any faster

What is meant by "substrate saturation of an enzyme"?

The active site changes to more tightly bind to the substrate

What is the "induced fit" model of enzyme:substrate interaction?

Enzymes speed up chemical reactions by lowering "Activation Energy, Ea"

What role do enzymes preform in cells?

Help with the specificity to the binding of the site.

What role do vitamins play with regard to coenzyme structure?

It denatures the protein in the cell

Why can't heat be used to increase speed of chemical reactions in cells?

E + S--> ES complex--> E + P

Write a reaction showing interaction of enzymes (E), substrate (S), and resulting products (P)