3.1 Mode of action of enzymes

Question 1

Enzymes (4)

Answer 1

–> globular proteins that catalyze reactions inside cells (intracellular enzymes)
or are secreted to catalyse reactions outside cells (extracellular enzymes)
–> biological catalysts

Question 2

enzyme specific three dimensional shape is determined by their sequence of ___

Answer 2

amino acids

Question 3

What makes up active site?

Answer 3

few amino acids

Question 4

enzyme molecule (3) (shape and structure)

Answer 4

coiled into a precise three-dimensional shape –tertiary proteins
with hydrophilic R groups on the outside of the molecules ensuring that they are soluble

Question 5

lock and key hypothesis (3)

Answer 5

enzyme has a particular shape into which the substrate fits EXACTLY.

substrate is held in place by temporary bonds which form between the substrate bonds

Question 6

When the enzyme and substrate combine is called …

Answer 6

enzyme - substrate complex

Question 7

lock and key
E + S –>

Answer 7

E-S complex –> product and enzyme available for resue

Question 8

Induced fit model (4)

Answer 8

enzyme molecules are more flexible
–> can change shape slightly as the substrate molecule enters the enzyme in order to ensure a perfect fit.
–> stresses the substrate reducing the activation energy of the reaction
changes in the R-group
–> becomes complimentary