1.
State what is meant by photosynthesis.
[1 mark]
- endothermic reaction that uses light to make glucose from CO₂ and water
JD SCIENCE
Bioenergetics
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by a limiting factor.
[1 mark]
- a factor in shortest supply that holds the rate down
3.
State what is meant by chlorophyll.
[1 mark]
- green pigment that absorbs light
4.
State what is meant by glucose in plants.
[1 mark]
- product used for respiration, stored as starch, used to make cellulose, proteins and oils
5.
State what is meant by aerobic respiration.
[1 mark]
- exothermic reaction using oxygen to release energy from glucose
6.
State what is meant by anaerobic respiration in muscle.
[1 mark]
- incomplete breakdown of glucose without oxygen, producing lactic acid
7.
State what is meant by anaerobic respiration in yeast.
[1 mark]
- fermentation producing ethanol and CO₂
8.
State what is meant by the stomata.
[1 mark]
- pores in the leaf that allow gas exchange
9.
State what is meant by xylem.
[1 mark]
- tissue that transports water and minerals from roots to leaves
10.
State what is meant by phloem.
[1 mark]
- tissue that transports dissolved sugars
11.
Amira is asked about photosynthesis in a AQA Biology paper.
(a) [2 marks]
- occurs in chloroplasts
(b) [3 marks]
- why the rate levels off at high light intensity
12.
Amira is asked about a limiting factor in a AQA Biology paper.
(a) [2 marks]
- light, CO₂ or temperature for photosynthesis
(b) [3 marks]
- why growers increase CO₂ in a greenhouse
13.
Amira is asked about chlorophyll in a AQA Biology paper.
(a) [2 marks]
- found in chloroplasts
(b) [3 marks]
- why a plant with yellow leaves photosynthesises more slowly
14.
Amira is asked about glucose in plants in a AQA Biology paper.
(a) [2 marks]
- can be converted to sucrose for transport
(b) [3 marks]
- why a starch test is used after a photosynthesis experiment
15.
Amira is asked about aerobic respiration in a AQA Biology paper.
(a) [2 marks]
- produces CO₂ and water
(b) [3 marks]
- why more energy is released than in anaerobic respiration
16.
Amira is asked about anaerobic respiration in muscle in a AQA Biology paper.
(a) [2 marks]
- releases less energy
(b) [3 marks]
- why an oxygen debt builds up
17.
A plant produces 12 cm³ of oxygen in 4 minutes. Calculate the rate.
[3 marks]
- 12/4
- Final answer: 3 cm³/min
18.
Light intensity is estimated as 1/d². If d = 20 cm, calculate 1/d².
[3 marks]
- inverse square
- Final answer: 2.50e-3
19.
Respiration releases 1200 J from 0.5 g of glucose. Calculate J per gram.
[3 marks]
- Final answer: 2400 J/g
20.
A leaf loses 0.8 g of water in 10 minutes. Calculate the transpiration rate in g/h.
[3 marks]
- ×6
- Final answer: 4.8 g/h
21.
Temperature rises from 10°C to 20°C and rate doubles. What would you expect from 20°C to 30°C if Q10 = 2, before denaturation?
[3 marks]
- Q10 idea
- Final answer: rate doubles again
22.
A potometer air bubble moves 24 mm in 2 minutes. Calculate the mean speed.
[3 marks]
- Final answer: 12.0 mm/min
23.
Amira carries out the photosynthesis required practical with pondweed. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: light intensity / colour / CO₂
- Dependent: bubbles per minute / volume of O₂
(b) [2 marks]
- temperature, same length of pondweed
- so the test is fair / only one variable is changed
(c) [2 marks]
- bubbles not the same size
24.
Amira carries out testing a leaf for starch. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: whether the leaf was destarched / covered
- Dependent: iodine colour
(b) [2 marks]
- same boiling time in ethanol
- so the test is fair / only one variable is changed
(c) [2 marks]
- not destarching the plant first
25.
Amira carries out the potometer transpiration practical. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: wind / temperature / humidity / light
- Dependent: distance moved by the bubble
(b) [2 marks]
- same leafy shoot
- so the test is fair / only one variable is changed
(c) [2 marks]
- air leak in the apparatus
26.
Amira carries out investigating respiration with germinating seeds and limewater or a respirometer. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: alive vs boiled seeds
- Dependent: CO₂ produced / volume change
(b) [2 marks]
- same mass of seeds
- so the test is fair / only one variable is changed
(c) [2 marks]
- temperature change affects gas volume
27.
Compare photosynthesis with aerobic respiration.
[4 marks]
- photosynthesis stores energy / endothermic
- respiration releases energy / exothermic
- equations are reverse
28.
Compare xylem with phloem.
[4 marks]
- xylem: water, one way, dead
- phloem: sugars, both ways, living
29.
Compare aerobic respiration with anaerobic respiration in muscle.
[4 marks]
- aerobic: more ATP, CO₂ + water
- anaerobic: lactic acid, oxygen debt
30.
Compare a palisade cell with a guard cell.
[4 marks]
- palisade: photosynthesis
- guard cell: controls stomatal opening
31.
Apply your knowledge of anaerobic respiration in yeast to this situation: CO₂ bubbles
[3 marks]
- CO₂ bubbles
32.
Apply your knowledge of the stomata to this situation: reduce water loss
[3 marks]
- reduce water loss