B3-Food & Ecosystems

Question 1

What factors affect the rate of reaction

Answer 1

Temperature
pH
Substrate Conc.

Question 2

How do I change the temperature to increase the rate of reaction

Answer 2

Increase it

Question 3

Why does increasing the temp. increase the rate of reaction

Answer 3

There are more collisions between the active site of the enzyme and the substrate

Question 4

What are Enzymes

Answer 4

Enzymes are biological catalysts

Question 5

What do Enzymes do

Answer 5

Speed up reactions

Question 6

What has happened to an enzyme when a substrate does not fit into it’s active site

Answer 6

It has denatured

Question 7

What happens if the pH of the environment surrounding an enzyme is too high or too low

Answer 7

It affects the bonds holding the active site together, the enzyme eventually denatures

Question 8

What is the optimum pH for MOST enzymes

Answer 8

It is neutral 7

Question 9

What happens if I increase the substrate conc.

Answer 9

The reaction begins to get faster

Question 10

what is the name of the model which describes the substrate fitting into the active site

Answer 10

Lock and key model

Question 11

what is respiration

Answer 11

Process of transferring energy from a molecule such as glucose

Question 12

How do animals produce energy

Answer 12

Animals consume glucose by breaking down the bio mass of organisms they eat

Question 13

What kind of reaction is respiration

Answer 13

Its exothermic

Question 14

what is exothermic

Answer 14

exothermic is the release of energy in a reaction

Question 15

Is respiration 1 or several chemical reactions

Answer 15

It is several chemical reactions

Question 16

What is ATP

Answer 16

ATP is a store of energy from respiration

Question 17

why do we have ATP

Answer 17

The energy from respiration cant be used directly by cells

Question 18

what is energy used for

Answer 18

Contracting muscles. making new molecules, breaking molecules and active transport

Question 19

what are the processors need for organism staying alive

Answer 19

Contracting muscles. making new molecules, breaking molecules and active transport

Question 20

where and when does respiration happen

Answer 20

All cells all the time

Question 21

what does aerobic respiration produce

Answer 21

it produces lots of ATP

Question 22

where does respiration happen in the prokaryotic cell happen

Answer 22

It happens in the cytoplasm

Question 23

where does respiration happen in the eukaryotic cell

Answer 23

It happens in the Cytoplasm and the Mitochondria

Question 24

When do human cells perform anaerobic respiration

Answer 24

During exercise . The body can’t meet the demand of oxygen from muscles so the muscles respire anaerobically. Produces lactic acid as a result

Question 25

When do plant root cells anaerobically respire

Answer 25

When the soil becomes waterlogged, there is no oxygen .

Question 26

When do bacterial cells respire anaerobically

Answer 26

When under the skin. There is very little oxygen, only bacteria, respiring anearobically survive

Question 27

Why is anaerobic respiration not as good as aerobic

Answer 27

It produces less energy per glucose molecule

Question 28

What is glucose anaerobically respired to make in humans

Answer 28

Glucose= Lactic acid . It is partially broken down glucose , so not all of the energy from the bonds in glucose are released

Question 29

What do plants and some micro organisms produce during anaerobic respiration

Answer 29

Glucose = Ethanol + CO2. Again Glucose is only partially broken down.

Question 30

how much Atp is produced in anerobic respiration

Answer 30

2 ATP is produced

Question 31

What does the enzyme catalase break down

Answer 31

Hydrogen Peroxide (H2O2)

Question 32

What does catalase make

Answer 32

Water and Oxygen

Question 33

What can you collect in the reaction metabolised by catalase

Answer 33

Oxygen

Question 34

How can you investigate the affect of temperature(or any factor) on enzyme activity

Answer 34

You can either measure how fast a product appears
OR
You can measure how fast a substrate disappears

Question 35

Why is the reaction catalysed by Catalase important

Answer 35

We can collect the O2 and measure how much is produced in a set time ie. we can measure how fast the reaction happens

Question 36

How do we measure the speed of the catalase reaction

Answer 36

1) Pipette X amount of H2O2 into a boiling tube .
2) Put the tube in the water bath at Y temperature (for 5 minutes so the tube is at the right temperature)
3) Set up the rest of the appartus so that water is in an upturned measuring cylinder in a tub of water. The measuring cylinder has a delivery tube in it and is attached to a bung.
4) Put some catalase in the H2O2 solution in the boiling tube and quickly attach the bung with the delivery tube.
5) Record how much oxygen is produced in the first minute , repeat three times until the reaction seems to stop producing oxygen (which will be in the upside down measuring cylinder)
6) Repeat at different temperatures

Question 37

When measuring a reaction w hat must you control

Answer 37

Any other variables e.g. when measuring the affect of temperature on a reaction you must measure other factors including; pH, potato(source of catalase)

Question 38

How do you calculate the rate of reaction

Answer 38

You calculate the mean volume of oxygen produced each minute (Volume/Time) Units will be cm3/second .