BIoenergetics

Question 1

What is the suns energy used for in plants?

Answer 1

To make food

Question 2

What does the plant manufacture glucose from?

Answer 2

The plant manufactures glucose from carbon dioxide and water using energy transferred from the environment to the chloroplasts by light

Question 3

Is photosynthesis endothermic or exothermic?

Answer 3

This is an endothermic reaction because photosynthesis needs an input of energy from the environment.

Question 4

What is the word equation for photosynthesis?

Answer 4

Carbon dioxide + water –(light)–> glucose + oxygen

Question 5

Symbol equation for photosynthesis?

Answer 5

6CO2 + 6H2O –(light)–> C6H12O6 + 6O2

Question 6

What type of reaction is photosynthesis?

Answer 6

An enzyme controlled reaction.

Question 7

Limiting factors for photosynthesis?

Answer 7

Carbon dioxide concentration, temperature, light intensity.

Question 8

What are the uses for the glucose made from photosynthesis?

Answer 8

1. To produce cellulose which strengthens plant cell walls.
2. To be converted into insoluble starch for storage inside cells or special areas like roots or bulbs.
   3.To be converted into amino acids for protein synthesis.
   Glucose is combined with nitrate ions absorbed from the soil. Specific amino acids join in long chains to make a named protein.
3. To produce fat or oil for storage.
   Seeds and nuts contain lots of fat or oil as an energy store.

Question 9

What is the definition of a limiting factor?

Answer 9

A factor which is not at an optimum level to enable maximum rate of photosynthesis e.g. temperature

Question 10

Name the raw materials needed by a plant for photosynthesis?

Answer 10

Carbon dioxide and water

Question 11

Name the green pigment present in plant cells.

Answer 11

Chlorophyll

Question 12

What is the role of chlorophyll?

Answer 12

To transfer energy from the environment and use it to synthesise glucose from carbon dioxide and water.

Question 13

Is respiration endothermic or exothermic?

Answer 13

Respiration is an exothermic reaction which means energy is transferred to the environment. Some of the energy is used inside cells and the rest will be transferred out of the cell.

Question 14

Why do living organisms need energy?

Answer 14

1. For movement. To enable muscles to contract in animals.
2. For keeping warm. To keep a steady body temperature in a cold environment.
3. For chemical reactions. To build larger molecules from smaller ones.

Question 15

Word equation for aerobic respiration in humans

Answer 15

glucose + oxygen —-> energy + carbon dioxide

Question 16

Symbol equation for aerobic respiration in humans

Answer 16

C6H12O6 + 6O2 —–> 6CO2 + 6H2O

Question 17

Where does aerobic respiration occur?

Answer 17

Inside mitochondria

Question 18

Anaerobic respiration equation in humans

Answer 18

glucose —> lactic acid

Question 19

Anaerobic respiration is plants equation

Answer 19

glucose ——> ethanol + carbon dioxide

Question 20

When does respiration occur in cells?

Answer 20

Continuous

Question 21

Why is fermentation of economic importance?

Answer 21

Used in the manufacture of bread and alcoholic drinks.

Question 22

Describe three ways in which the body responds to vigorous exercise in order to ensure sufficient oxygen reaches the muscle cells

Answer 22

Increase in heart rate; increase in breathing rate and increase in breath volume.

Question 23

If exercise carries on for a long time, what happens to the muscles?

Answer 23

Muscles become fatigued and stop contracting efficiently.

Question 24

What are carbohydrates made from?

Answer 24

Many glucose molecules

Question 25

What are lipids made from?

Answer 25

1 molecule of glycerol and 3 molecules of fatty acid

Question 26

What is protein made from?:

Answer 26

Many amino acids

Question 27

What is metabolism?

Answer 27

Metabolism is the sum of all reactions which occur in a cell or body.

Question 28

Describe the process for removing lactic acid from the body.

Answer 28

Blood flows through the muscle cells and transports the lactic acid to the liver where it is converted back into glucose. The glucose is then used in aerobic respiration or stored as glycogen.

Question 29

What is meant by the oxygen debt?

Answer 29

The amount of extra oxygen which is needed to remove all lactic acid from the body is known as the oxygen debt.