R2101 4.2 Describe aerobic and anaerobic respiration and the factors that affect them

Question 1

What is respiration?

Answer 1

The process by which cells release energy contained in carbohydrates in order to fuel the growth of the plant

Question 2

Where does respiration take place?

Answer 2

In the mitochondria in ALL plant cells

Question 3

When does respiration take place?

Answer 3

Respiration takes place continuously, whereas photosynthesis takes place only when light is present

Question 4

What are the inputs of respiration? (2)

Answer 4

1. Carbohydrates - made by photosynthesis and transported in the phloem in a soluble form (types of glucose and sugars) and stored in flower, roots or special storage organs like tubers or corms.
2. Oxygen - a by product of photosynthesis but extra oxygen can be obatined from atmosphere through stomata by gaseous exchange

Question 5

What are the outputs if respiration? (3)

Answer 5

1. Carbon dioxide - reused in photosynthesis or released through the stomata
2. Water released as vapour from the stomata
3. Energy that fuels growth

Question 6

Aerobic respiration equation

Answer 6

glucose+oxygen > carbon dioxide + water +energy

Energy is stored as ATP

Question 7

Two stage process of respiration

Answer 7

Stage 1: Doesnt need oxygen
This splits the glucose
It release some carbon dioxide and a little energy

Stage 2: Does need oxygen
This uses the oxygen to break down all that remains of the glucose into carbon dioxide, water and a LOT of energy

Question 8

Anaerobic respiration equation

Answer 8

glucose > alcohol (ethanol) + carbon dioxide + energy

Releases little energy - keeps plant ticking over.

Question 9

What factors affect the efficiency of respiration? (2)

Answer 9

1. Oxygen
2. Temperature

Question 10

Effect of lack of Oxygen on respiration

Answer 10

Without oxygen there is a build up of ethanol in the plant.
Therefore anaerobic respiration takes plants - until the build up of ethanol kills the roots.

Question 11

Effect of temperature on respiration? (2)

Answer 11

1. As temperature increases the rate of respiration increases and the plant turns more sugars into energy for growth
2. As it gets colder the plant slows down its respiration rate, growth slows down or ceases and less energy is needed for cell division

Question 12

Time of day differences betwen photosynthesis and respiration ?(4)

Answer 12

1. Photosynthesis takes place only in the green parts of the plant
2. Respiration takes place in ALL parts of the plant
3. Photosynthesis takes place only in sunlight
4. Respiration takes place ALL the time

Question 12

Differences betwen photosynthesis and respiration ?(4)

Answer 12

1. Photosynthesis takes place only in the green parts of the plant
2. Respiration takes place in ALL parts of the plant
3. Photosynthesis takes place only in sunlight
4. Respiration takes place ALL the time

Question 13

Horticultural implications / applications for respiration (4)

Answer 13

1. Waterlogging
2. Propagation
3. Produce storage
4. Seed storage

Question 14

Waterlogging and respiration (2)

Answer 14

1. Anaerobic respiration will occur in waterlogged soils or in waterlogged compost in pots.

2.The ethanol produced will be toxic to the roots and the roots will start to dies - reducing water uptake so the plants will wilt

Question 15

Cuttings Propagation and respiration (3)

Answer 15

1.Cuttings should be potted in a mix that contains plenty of air
2. For cuttings to produce roots there must be active cell division, and high energy is need to fuel this.
3. Bottom heat in a propagator will speed up respiration and so the formation of new tissues

Question 16

Produce storage and respiration (5)

Answer 16

1. Fruits, flowers and vegetables continue to respire after harvesting -using up stored sugars - causing an apple to shrivel
2. Low temperatures can slow respiration - be careful not to damage tropical fruits such as banana’s
3. Reduce carbon dioxide in the atmosphere in ‘controlled atmosphere storage’
4. Leafy vegetables decay rapidly as they have very little stored food, root vegetables take longer to break down.
5. Respiration gives off water vapour, and some energy is give off as heat, giving perfect conditions for diseases unless storage is controlled.

Question 17

Seeds and respiration

Answer 17

1. For efficient storage most seeds are kept in sealed containers at low temperature to restrict oxygen levels
2. At point of germination seeds respires anaerobically until seed coat splits and oxygen can enter
3. The respiration rate rises rapidly to convert the foodstore to radical and plumule growth