Key area 2.1

Question 1

What is cell metabolism

Answer 1

Sum total of all chemical reactions within a cell

Question 2

What is a metabollic pathway

Answer 2

Enzyme conrtolled sequence of chemical reactions in the cell

Question 3

Name the 2 types of metabollic pathways

Answer 3

Catabolic

Anabolic

Question 4

Describe catabolic

And give an example

Answer 4

Brings about the break down of complex molecules into simplier ones

Releases energy
Protein - Amino acids

Question 5

Describe anabolic pathways

Answer 5

Brings about the biosynthesis or molecules from smaller ones

Requires energry
Amino acids - proteins

Question 6

What is the advantage of having a reversible pathway

Answer 6

Allows the cells to regulate the pathway

Question 7

hat are steps in metabolic pathways regulated by

Answer 7

Enzymes

Question 8

What is the function of the cell membrane

Answer 8

Allows the entry and exit of substances in the cell

Question 9

What is the cell membrane made of

Answer 9

Phospholipids and embedded proteins

Question 10

What is the purpose of having membrane bound compartments in cells

Answer 10

Allows compartmentalisation which means reactions can be kept seperate in cells

Question 11

What is the advantage to cells of having many small compartments

Answer 11

Higher surface area allows high concentration and high reaction rates

Question 12

Name and describe the types of proteins found in the membrane

Answer 12

Enzymes: Catalyse a specific reaction
Channel (Pore): Allows specific mols and ions to pass through by passive transport
Carrier (Pump): Binds to specific mols or ions temporarily allowing them to pass by active transport
Structual protein: Help maintain the shape of the cell

Question 13

How do enzymes speed up chemical reaction

Answer 13

Speed up chemical reactions by lowering activation energy

Bringing substrate close

Question 14

Explain the induced fit model

Answer 14

• Active sit has a flexible structure
• Active site alters its shape to fit substrate more closely
• This increases the rated reaction as it helps orient the substrate in right way for reaction to occur

Question 15

State the affinities an enzyme has for a product and substrate

Answer 15

Enzymes have a high affinity for the substrate

Enzyme have a low affinity for the product

Question 16

What is enzyme co-factor

Answer 16

Molecules needed to make an enzyme more efficient

Question 17

Describe what is meant by a multi-enzyme complex

Answer 17

A group of enzymes working together to acheive one step in a metabollic pathway

Question 18

3 ways an enzyme activity can be regulated

Answer 18

• Controlling number of enzymes in a cell
• Keeping reactants in compartments
• Changing enzyme shape most effective

Question 19

What is an inhibitor

Answer 19

Reduces rate of reaction by interfering with enzyme in some way

Question 20

Name the types of inhibition

Answer 20

• Competitive
• Non competitive
• Feedback

Question 21

Describe how competitive inhibiton works

Answer 21

• Similar shape to substrate
• Binds to enzyme active site but remain inactive
• Less substrate can bind to enzyme
• Temporary as increasing substrate concentration will outnumber inhibitors

Question 22

Describe non competitive inhibiton

Answer 22

• Binds to substrate only other site not active site
• Causes whole enzyme to change structure
• No longer binds with specific substrate
• May or may not be temporary as these inhibitors do not compete

Question 23

Describe how feedback initiation works

Answer 23

The product binds to an enzyme earlier on in the pathway

It’s bind to another site than the active site

This changes the shape on the enzyme meaning it can no longer bind to its specific substrate

Question 24

Describe how feedback initiation works

Answer 24

The product binds to an enzyme earlier on in the pathway

It’s bind to another site than the active site

This changes the shape on the enzyme meaning it can no longer bind to its specific substrate