4 Bioenergetics

Question 1

Is photosynthesis endothermic or exothermic?

Answer 1

Endothermic

Question 2

State the equation of photosynthesis.

Answer 2

6CO2 + 6H2O –> C6H12O6 + 6O2

Question 3

Where does photosynthesis occur in the cell?

Answer 3

Chloroplast

Question 4

What is photosynthesis?

Answer 4

Building glucose from carbon dioxide and water using light

Question 5

Name the pigment in chloroplasts that absorbs light.

Answer 5

Chlorophyll

Question 6

State an adaptation of the leaf for efficient photosynthesis.

Answer 6

Broad leaves/Thin/Have chlorophyll/Air spaces/Guard cells to regulate stomata opening

Question 7

How does higher light intensity affect the rate of photosynthesis?

Answer 7

Increase

Question 8

Apart from light and carbon dioxide concentration, name one other limiting factor of photosynthetic rate.

Answer 8

Temperature/Chlorophyll levels

Question 9

Why would photosynthetic rate decrease at higher temperatures?

Answer 9

Enzymes become denatured

Question 10

Name one use of glucose in plants.

Answer 10

Respiration/Make and strenghten cellulose cell wall/Make starch for storage/Make lipids as energy store

Question 11

Why do plants need nitrates for good growth?

Answer 11

Make proteins

Question 12

State one factor to maintain in a greenhouse for optimal plant growth.

Answer 12

High CO2 levels/Constant light/Appropriate temperatures/Regulate watering

Question 13

Define ‘aerobic respiration’.

Answer 13

Exothermic reaction that breaks down glucose to release energy using oxygen

Question 14

State the equation of aerobic respiration.

Answer 14

Glucose + Oxygen –> Carbon dioxide + Water

Question 15

Is respiration endothermic or exothermic?

Answer 15

Exothermic

Question 16

Where does aerobic respiration occur in the cell?

Answer 16

Mitochondria

Question 17

Give one importance of respiration.

Answer 17

Metabolic reactions (eg. Build)/Muscle contraction/Mainting body temp/Active transport

Question 18

State one response of the body to exercise.

Answer 18

Increase heart rate/breathing rate/Glycogen coverted to glucose/Increase blood flow to muscles

Question 19

What happens to the glycogen stored in muscles when you exercise?

Answer 19

Converted into glucose for respiration

Question 20

What is anaerobic respiration?

Answer 20

Breakdown of glucose to release small amount of energy without the use of oxygen

Question 21

Name the toxic substance produced by anaerobic respiration.

Answer 21

Lactic acid

Question 22

State an effect on your body after anaerobic respiration.

Answer 22

Muscle fatigue

Question 23

Define ‘oxygen debt’.

Answer 23

Amount of oxygen needed to break down lactic acid

Question 24

What do plants make in anaerobic respiration?

Answer 24

Ethanol and carbon dioxide

Question 25

Give one use of yeast doing anaerobic respiration.

Answer 25

Making bread/alcohol

Question 26

Give one example of a metabolic reaction in cells.

Answer 26

Convert glucose to glycogen,starch,cellulose/Make lipids/proteins/Respiration/Photosynthesis/Breakdown of proteins

Question 27

State a function of liver.

Answer 27

Detoxification/Breakdown of old blood cells/Remove lactic acid (convert to glucose)

Question 28

Pollen grains grow down into female flowers on their way to fertilising an egg. In the flower tissue, oxygen concentrations are low. Suggest which molecules are produced as a pollen grain respires

Answer 28

Ethanol and carbon dioxide. Pollen grains can respire anaerobically as the pollen tube moves towards an egg.

Question 29

Describe how anaerobic respiration is important in bread making

Answer 29

The anaerobic respiration of) yeast is involved. Bubbles of carbon dioxide make the bread rise

Question 30

Define the inverse square law.

Answer 30

For a type of electromagnetic radiation such as light, as the distance from the light source increases, light intensity is inversely proportional to the square of the distance.

Question 31

Explain how some plants are adapted to growing in the shade

Answer 31

Shade-adapted plants produce more chlorophyll (so that they are more efficient at absorbing light. This allows them to photosynthesise at lower light intensities.

Question 32

Describe an experiment to investigate the effect of the presence of chlorophyll on photosynthesis

Answer 32

1) use a plant with variegated leaves
2) kill and preserve a leaf by dipping it in boiling water
3) decolorize/remove chlorophyll from the leaf by immersing it in hot alcohol
3) dip it in water to soften it
4) place in a Petri dish and flood with iodine solution
5) a blue-black colour indicates the presence of starch
6) the parts of the leaf that contained chlorophyll will stain blue-black, indicating that chlorophyll is required for photosynthesis

Question 33

A student investigated the effect of different parts of the spectrum on photosynthesis. She covered three test tubes containing pond weed with plastic filters. She counted the bubbles produced over one minute intervals. Suggest how the student could check the repeatability of her results.

Answer 33

by carrying out the experiment/repeating it several times
the student can see how close they are together, ie repeatable