4. enzyme action

Question 1

enzymes speed up chemical reactions by acting as

Answer 1

biological catalysts

Question 2

enzymes catalyse which reactions

Answer 2

metabolic reactions

at a cellular level e.g. respiration and for the organism as a whole e.g. digestion

Question 3

enzymes can affect

Answer 3

structures in organisms e.g. involved in production of collagen an important protein in connective tissue
and functions e.g. respiration

Question 4

enzymes can be

Answer 4

intracellular (within cells) or extracellulare (outside cells)

Question 5

enzymes are

Answer 5

proteins

Question 6

enzymes have an

Answer 6

active site which has a specific shape

Question 7

active site is the part of the enzyme where

Answer 7

the substrate molecules bind to

Question 8

enzymes are highly specific due to their

Answer 8

tertiary structure

Question 9

enzyes lower the amount

Answer 9

of activation energy that is needed (making reactions happen at a lower temperature thus speeding up reaction)

Question 10

when a substrate fits to an enzyme it forms an

Answer 10

enzyme substrate complex

Question 11

why does the enzyme substrate complex lower the activation energy

Answer 11

1. if 2 substrate molecules need to be joined being attached to the enzyme holds them closer together reducing any repulsion between the molecules so they can bond more easily.
2. if the enzyme is catalysing a breakdown reaction fitting into active site puts strain on bonds in substrate so substrate molecule breaks up more easily

Question 12

lock and key model

Answer 12

substrate fits into enzyme same way a key fits into a lock

Question 13

problems with lock and key model

Answer 13

new evidence showed enzyme-substrate complex changed shape slightly to complete fit locking the substrate more tightly to the enzyme -> induced fit model

Question 14

how does induced fit model help to explain why enzymes are so specific

Answer 14

substrate doesnt only have to be right shape to fit in the active site
it has to make active site change shape the right way aswell

Question 15

enzyme properties relate to their tertiary structure

Answer 15

1. enzymes are very specific (usually only catalyse 1 reaction)
2. only 1 complimentary substrate will fit in active site
3. active sites shape is determined by enzymes tertiary structurre (which is determined by its primary structure)
4. each different enzyme has a different tertiary structure so a different shaped active site.
   5

Question 16

tertiry structyre of an enzyme may be altered by

Answer 16

changes in PH ot temperature

Question 17

primary structure of a protein is determined by a

Answer 17

gener

Question 18

if a mutation occurs in the gene that codes for an enzyme

Answer 18

the tertiary structure of the enzyme produce could be changed