Unit 2- Energy and Metabolism

Question 1

ways chemical catalysts and enzymes are the same (3)

Answer 1

1) They speed up chemical reactions by lowering the activation energy
2) They can only speed up reactions that are possible
3) They aren’t used up or permanently modified by the reactions they catalyze.

Question 2

Characteristics specific to enzymes (2)

Answer 2

1) Enzymes are specific for a very small number of reactants (substrates)
2) Enzymatic activity is often regulated (controlled) by the cell.
→Essential to maintain homeostasis

Question 3

The active site will only allow the correct substrate to enter
because (2):

Answer 3

1)It has a very specific shape
2)The electrical charges of the amino acid R-groups in the active site are complementary to those of the enzyme’s
substrate, both in their polarity (- or +) and in their location

Question 4

name reasons why enzymes are acting 10 million times faster than chemical catalysts (2)

Answer 4

→Enzymes actively grab substrates instead of just relying on them “floating” close to each other by chance
→Enzymes force the substrates together in the correct position for a reaction to occur

Question 5

name four major mechanisms by which the cell can regulate
its enzymes.

Answer 5

1) Synthesis based on need
2) Synthesis of inactive enzymes
3) Allosteric regulation
→often uses feedback inhibition
4) Competitive inhibition

SSAC