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Flashcards in 2: Cell Respiration Deck (13):
1

What do all living cells need?

a continual supply of energy

2

What is energy used by cells used for? Where does this energy come from (chemically)?

- a wide range of processes including active transport and protein synthesis
- energy in form of ATP (adenosine triphosphate)

3

How do cells get ATP?

- produce it themselves through cell respiration:
- carbon compounds e.g. glucose or fat are carefully broken down and the energy released by doing this is used to make ATP

4

Define 'cell respiration'.

controlled release of energy from organic compounds to produce ATP

5

Is ATP a good source of energy?

yeaa boi - immediately available as an energy source:
- it can diffuse to any part of the cell and release its energy within a fraction of a second

6

Contrast aerobic cell respiration and anaerobic cell respiration.

1. oxygen used?
- aerobic: yes
- anaerobic: no

2. substrate:
- aerobic: glucose or lipids
- anaerobic: glucose only

3. yield of ATP per glucose
- aerobic: large
- anaerobic: small

4. products:
- aerobic: CO2 and water
- anaerobic:
humans: lactate
yeast: CO2 and ethanol

7

Draw a flow diagram of aerobic cell respiration. (p32)

pyruvate -> large amount of ATP + water + CO2

8

Draw a flow diagram of anaerobic cell respiration. (p32)

glucose -> pyruvate + small amount of ATP

9

State an advantage of anaerobic respiration over aerobic respiration when providing energy for muscles. When is anaerobic respiration often used?

- although anaerobic makes less ATP per glucose, it can supply ATP at a more rapid overall rate than aerobic (for a short time - about 2 mins)
- during very vigorous exercise e.g. sprinting or weight lifting

10

Why can we only anaerobically respire for a very short time?

- lactate (lactic acid) and hydrogen ions are produced by anaerobic respiration
- hydrogen ions lower the pH of blood
- after ~2mins, concentration of hydrogen ions is too high, making blood too acidic, so aerobic cell respiration must be used

11

What are the two products of anaerobic respiration in yeast?

ethanol and CO2

12

How is CO2 (produced by anaerobic respiration of yeast) used?

In baking industry:
- yeast mixed into dough before baking
- rapidly uses up all oxygen present and then produces ethanol and CO2
- CO2 forms bubbles making bread rise, and less dense (leavened)
- when baked, ethanol evaporates

13

How is ethanol (produced by anaerobic respiration of yeast) used?

in brewing and biofuel industries:
- yeast cultured in liquid containing sugar and other nutrients, but not oxygen (therefore anaerobic respiration)
- ethanol concentration rises, at 15% ethanol -
- fermentation ends before ethanol conc becomes toxic to yeast
- CO2 bubbles into atmosphere

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