Enzymes

Question 1

Recall

Answer 1

• All enzymes are protiens, but not all protiens are enzymes
• biological catalysts that consist of complex protien structures
• Speed up or slow down reactions by lowering the activiation energy
  *They are reusable (don’t get used up in reactions)

Question 2

Why are they important to biological systems?

Answer 2

Because other factors that increase reaction rate (such as temperature or concentration) are also known to denature biological proteins

Question 3

Substrate

Answer 3

• A molecule or compound that is acted upon by the enzyme and often fits into the entire enzyme itself and “fits” in the active site
• Ex. starch

Question 4

Active site

Answer 4

The pysical opening in which the substrate attaches

Question 5

Induced fit model

Answer 5

Model that explains how some substrates are able to alter and improve the shape of an active site so that the enzyme functions better

Question 6

What does Induced fit model suggest?

Answer 6

That the “Lock and key” fit is not necessarily accurate

Question 7

Cofactors

Answer 7

• Inorganic substances that aid in the enzymes funtction
• Minerals
• Ex. Ca2+, Mn2+, Na+ etc

Question 8

Coenzymes

Answer 8

*Organic substances that aid enzyme function
Ex. Any type of vitamins and their derivatives

Question 9

Allosteric sites

Answer 9

Receptor sites on an enzyme (other than the active site) where the controlling molecule can plug in and affect enzyme function

Question 10

Receptor site

Answer 10

A site on a membrane or molecules where small attachments can join

Question 11

Catalytic cycle: Step 1

Answer 11

The substrate, lactose, binds to enzyme B-galactosidase, forming an enzyme- substrate complex.

Question 12

Catalytic cycle: Step 2

Answer 12

B-Galactosidase catalyzes the hydrolysis of the bond between the two sugars of lactose, and the products are released

Question 13

Catalytic cycle: Step 3

Answer 13

The enzyme can catalyze another reaction