Respiration

Question 1

respiration

Answer 1

the breakdown of food (carbs) to release energy

Question 2

respiration formula

Answer 2

c6h12o6 + 6o2 —-enzymes—> 6co2 + 6h2o + energy

Question 3

aerobic respiration

Answer 3

the breakdown of food in the presence of oxygen to release energy

Question 4

anaerobic respiration

Answer 4

the breakdown of food with no oxygen to release energy

Question 5

fermentation

Answer 5

another term for anaerobic respiration in yeast cells (no oxygen required)

applications:
baking, brewing

Question 6

fermentation in muscle

Answer 6

glucose –> lactic acid + very little energy

Question 7

fermentation in yeast

Answer 7

glucose –> ethanol + carbon dioxide + very little energy

Question 8

biotechnology

Answer 8

the use of living things (cells and enzymes) to manufacture useful products

Question 9

bioreactor

Answer 9

a vessel in which living cells, organisms or yeast are placed in to make a useful product

Question 10

immobilised cells

Answer 10

cells that are attached to an inert substance by physical or chemical means

Question 11

stage 1 glycolysis

Answer 11

location: cytosol
conditions: anaerobic
amount of energy released: very little (partial break down of glucose)

1. break down of glucose into 2 pyruvates (3 carbon molecules)
2. energy is released, picked up by ADP+P to form ATP+ water
3. 2e- and H+ released, picked up by NAD+ to form NADH

Question 12

fate of pyruvate when oxygen is present

Answer 12

taken to mitochondria
loses a co2
loses 2e- and H+ picked up by NAD+ to form NADH
broken down to 2 carbonacetyl group: acetyl coenzyme A

Question 13

fate of pyruvate when oxygen is not present

Answer 13

remains in cytosol
in yeast cells: pyruvate is converted to ethanol and carbon dioxide
in animal cells: pyruvate is converted to lactic acid

Question 14

stage 2 Krebs Cycle and electron transport chain

Answer 14

location: mitochondria
conditions: aerobic
amount of energy released: more than first stage

Question 15

describe the Krebs Cycle

Answer 15

1. acetyl group broken down to release carbon dioxide, hydrogen ions, electrons
2. carbon dioxide released as waste gas
3. NADH produced when 2e- and H+ are picked up by NAD+
4. ATP produced when energy is lost and picked up by ADP+P

Question 16

describe the electron transport chain

Answer 16

1. NADH from krebs broken down to hydrogen ions and electrons
2. electrons lose energy as they move through different carriers, energy released by e-

Question 17

products of electron transport chain

Answer 17

energy released forms ATP

2H+ ions and 2e- combine with oxygen to form water

Question 18

to prepare and show the production of alcohol by yeast

Answer 18

control: no yeast in glucose solution

1. boil a glucose solution (creates anaerobic conditions)
2. allow solution to cool
3. add yeast
4. add layer of oil
5. attach airlock to conical flask
6. add limewater to airlock (to show presence of carbon dioxide)
7. leave both in a water bath at 30°

Question 19

iodoform test

Answer 19

1. filter solution
2. add an equal volume of potassium iodine to filtrate- colour change : brown to colourless
3. add sodium hypochlorite
4. place in water bath at 50-60°
5. allow to cool

pale yellow crystals = ethanol present
colourless to yellow = alcohol has been produced