Enzymes

Question 1

Define enzyme

Answer 1

A protein that speeds up a reaction, but is not changed by the reaction

• Organic catalyst
• Decreases the amount of energy needed to make the reaction happen
• Reduces activation energy
• Allows reactions to occur fast enough to match the body’s requirements

Question 2

Define activation energy

Answer 2

The energy needed to start a chemical reaction

Question 3

Define substrates

Answer 3

Molecules that enzymes react with

Question 4

Factors affecting enzyme activity

Answer 4

• Concentration
• Temperature
• pH
• Presence of co-factors

Question 5

How does concentration affect enzyme activity?

Answer 5

• More concentration = faster reactions

Question 6

How does temperature affect enzyme activity?

Answer 6

• Higher temperature = faster reactions (up to 50 degrees)

- Denature

Question 7

How does pH affect enzyme activity?

Answer 7

Acidity

Question 8

How does the presence of co-factors affect enzyme activity?

Answer 8

Required for reaction to take place

Question 9

Define denatured

Answer 9

When an enzyme is not able to function properly due to changes in its active site

Question 10

Define catabolic

Answer 10

Breaking down a large molecule to smaller molecules

Question 11

Define anabolic

Answer 11

Small molecules combined to make a large molecule

Question 12

Why do cells need energy to do work?

Answer 12

• Make new molecules
• Building membranes and organelles
• Moving molecules in and out of the cell
• Movement

Question 13

Types of metabolism

Answer 13

• Catabolism

- Anabolism

Question 14

Where does a cell get energy?

Answer 14

• Food is broken down to a form the cell can use

- Extra energy is stored in the ATP molecule, a nucleotide

Question 15

Define ATP

Answer 15

• Adenosine triphosphate

- A molecule made up of adenine, ribose and 3 phosphate groups

Question 16

How does ATP work?

Answer 16

• Energy is stored in the bond between the second and third phosphate group
• When bond is broken, energy is released and ADP is formed

Question 17

ADP

Answer 17

Adenosine diphosphate

Question 18

Equation for ATP (energy currency)

Answer 18

ATP ADP + Phosphorus + Energy

Question 19

How do cells make energy?

Answer 19

• Cells make energy via respiration

- Mostly takes place in the mitochondria

Question 20

Equation for respiration

Answer 20

O2 + Glucose –> CO2 + Water + Energy

Question 21

Define respiration

Answer 21

The process of breaking down food molecules to release energy
- Occurs in the mitochondria

Question 22

Types of respiration

Answer 22

• Aerobic (requires oxygen)

- Anaerobic (requires an absence of oxygen)

Question 23

Define cellular respiration

Answer 23

The process where organic molecules from food are broken down in the cells to release energy.
Examples:
- Glucose
- Amino acids 
- Fatty acids
- Glycerol

Question 24

What can the energy from the breakdown of foods be used for?

Answer 24

• Building complex molecules
• Cell division/growth
• Movement of cell organelles and whole cells
• Maintaining cell organisation
• Active transport
• Transmission of nerve impulses

Question 25

How is the energy stored from cellular respiration?

Answer 25

• As glucose is broken down, 60% of the energy released is heat, used to maintain body temperature
• Remaining energy is used to form ATP