enzymes in biochemical pathways

Question 1

enzyme

Answer 1

• a catalyst
• required for all processes in a cell

Question 2

catalyst

Answer 2

allows a reaction to occur a lower energy levels

Question 3

specificity of enzymes

Answer 3

• enzymes act of a specific compound called a substrate
• enzymes are highliy specific and work by binding to their substrate

Question 4

what is the part of the enzyme that binds to the substrate?

Answer 4

active site

Question 5

enzymes- working

Answer 5

• the enzyme moves the atoms in the molecule so that bonds a more easily broken/formed

Question 6

what do enzymes do?

Answer 6

• some help to synthesise products, others digest a substrate into multiple molecules
• enzymes are not ‘used up’ in a reaction: they can perform the same reaction over and over

Question 7

biological pathways

Answer 7

• very complicated
  -require multiple enzymes before reaching a final product

Question 8

lock and key model

Answer 8

• the substrate fits perfectly into the active site

Question 9

induced fit model

Answer 9

the shape of the active site often varies slightly from the shape of the substrate before binding

• the substrate induces a change in the shape of the active site

Question 10

building of larger molecules

Answer 10

forming chemical bonds
- requires energy input (ATP)

e.g, photosynthesis

Question 11

breakdown of macro molecules

Answer 11

breaking chemical bonds
- releases energy (ATP)

e.g, digestion of proteins

Question 12

what are coenzymes

Answer 12

• small organic (C-H bonds) non-protein molecules
• when carrying something they are ‘loaded’ when they are not carrying something they are ‘unloaded’

Question 13

what do coenzymes do?

Answer 13

• loosely bind to the active site of the enzyme assisting in catalysing reactions
• move energy, protons and electrons between reactions in the cell.

Question 14

ATP- a familiar coenzyme

Answer 14

• energy is released from ATP when the bond to the third phosphate is broken
• they need to be recycled back to ATP before they can be reused

Question 15

denaturation

Answer 15

irreversible change in the protein structure resulting in permanent loss of protein function

Question 16

critical temperature

Answer 16

the temperature at which denaturation of enzyme molecules begins to occur

Question 17

competitive inhibitors

Answer 17

bind at the active site, blocking the substrate

Question 18

non- competitive inhibitors

Answer 18

bind at an allosteric site, causing a change in the active site