Topic 4- Bioenergetics

Question 1

What is aerobic respiration?

Answer 1

Exothermic reaction- glucose reacts with oxygen to release energy used by cells

Question 2

State the word equation for photosynthesis

Answer 2

Carbon dioxide + water -> glucose + oxygen

Question 3

Is photosynthesis exothermic or endothermic?

Answer 3

Endothermic- energy transferred from environment to chloroplasts by light

Question 4

What are 3 leaf adaptations which maximise photosynthesis rate?

Answer 4

Broad leaves- maximise surface area
Chlorophyll present- trap light energy
Guard cells- control opening of stomata for gas exchange

Question 5

What are the 4 main factors that affect the rate of photosynthesis?

Answer 5

1. Temperature
2. Light intensity
3. CO2 concentration
4. Amount of chlorophyll

Question 6

How does temp affect rate of photosynthesis?

Answer 6

Increasing temp increases rate
Kinetic energy of particles is increased
Rate decreases past certain temp as enzymes become denatured

Question 7

How does light intensity affect the rate of photosynthesis?

Answer 7

Increasing light - increases rate

Until another factor becomes limiting

Question 8

How does CO2 concentration affect the rate of photosynthesis?

Answer 8

Increasing CO2- increases rate
Until another factor becomes limiting
As CO2 is required to make glucose

Question 9

How does amount of chlorophyll affect the rate of photosynthesis?

Answer 9

Decreasing chlorophyll- decreases rate

It is required to absorb light energy

Question 10

What is a limiting factor?

Answer 10

Environmental factor that can restrict the rate of photosynthesis

Question 11

What are 3 different uses of the glucose produced during photosynthesis?

Answer 11

Respiration
Cellulose (strength)
Lipids (energy storage)

Question 12

What is the word equation for aerobic respiration?

Answer 12

Glucose + oxygen -> CO2 + water

Question 13

Where does aerobic respiration take place?

Answer 13

Mitochondria

Question 14

Why do orangisms require energy produced by respiration?

Answer 14

Synthesis of larger molecules
Muscle contraction
Active transport

Question 15

What is anaerobic respiration?

Answer 15

Exothermic reaction

Glucose broke down to release energy in the absence of oxygen

Question 16

What is the equation for anaerobic respiration?

Answer 16

Glucose -> lactic acid

Question 17

Why is anaerobic respiration less efficient than aerobic respiration?

Answer 17

Glucose not completely broken down so less energy transferred

Question 18

Why can anaerobic respiration lead to muscle fatigue?

Answer 18

Lactic acid builds up in muscles- prevent efficient contraction

Question 19

What is an oxygen debt?

Answer 19

Amount of oxygen needed to convert lactic acid back into glucose after anaerobic respiration

Question 20

What is fermentation?

Answer 20

Type of anaerobic respiration that occurs in yeast cells

Question 21

What is the equation for fermentation?

Answer 21

Glucose -> ethanol + CO2

Question 22

Why is fermentation important?

Answer 22

Used in production of bread and alcoholic drinks

Question 23

What are the differences between aerobic and anaerobic respiration?

Answer 23

1. Aerobic requires oxygen
2. Aerobic produces CO2+H2O, anaerobic produces lactic acid
3. Aerobic transfers more energy

Question 24

How do muscles store glucose?

Answer 24

As glycogen

Question 25

What changes in body take place when muscular activity increases?

Answer 25

Breathing rate increases- increases rate of gas exchange
Heart rate increases- increases flow of oxygenated blood to muscles
Stored glycogen converted back to glucose

Question 26

How is lactic acid transported away from muscles?

Answer 26

Blood flow through muscles transports LA back to liver; oxidised back to glucose

Question 27

What is metabolism?

Answer 27

Sum of all reactions taking place in a cell or organism

Question 28

How d cells use energy transferred by respiration?

Answer 28

Continuously carry out processes which lead to the synthesis of new molecules