respiration

Question 1

define aerobic respiration

Answer 1

the controlled release of energy from food using oxygen

Question 2

what is the chemical equation for aerobic respiration

Answer 2

C6H1206 +602 –> 6Co2 + 6H2O + energy

Question 3

what is the first stage of aerobic respiration

Answer 3

glycolysis, it takes place in the cytosol

Question 4

does glycolysis require oxygen

Answer 4

no

Question 5

is glycolysis a high or low energy process

Answer 5

low energy

Question 6

what are the products of glycolysis

Answer 6

pyruvic acid, 2ATP molecules, water

Question 7

is stage 2 aerobic or anaerobic

Answer 7

aerobic, O2 is needed

Question 8

where does stage two take place

Answer 8

in the mitochondria

Question 9

what is formed from pyruvate in stage two

Answer 9

acetyl coenzyme A (acetyl coA)

Question 10

how does NADH form

Answer 10

pyruvic acid loses two high energy electrons which combine with NAD+ and a proton to form NADH

Question 11

where does NADH go at the end of stage two

Answer 11

it enters an electron transport system

Question 12

where does acetyl coA go after being formed in stage two

Answer 12

it enters a series of reactions called the krebs cycle

Question 13

where does the krebs cycle take place

Answer 13

the lumen of the mitochondria

Question 14

is oxygen required for the krebs cycle

Answer 14

yes

Question 15

what happens to the acetyl coA during the krebs cycle

Answer 15

it is broken down into carbon dioxide and protons

Question 16

describe the main events of the krebs cycle

Answer 16

1. acetyl coA combines with a 4 carbon molecule to form a 6 carbon molecule. 2. this 6 carbon molecule is broken down by releasing a Co2 and removing 2H which containes 2 electrons. 3. these two electrons and a proton combine with NAD+ to form NADH. 4. The five-carbon molecule releases another Co2 and 2H to form NADH. 5. one molecule of ATP + water are made from ATP + P. 6. another 2H are removed to form NADH.

Question 17

what are the products of the krebs cycle

Answer 17

3 NADH molecules, two Co2 molecules, one ATP + water

Question 18

outline the main events of the electron transport system

Answer 18

NADH formed in the krebs cycle enters an eectron transport chain. High energy electrons are passed from the NADH to electron acceptors. As this happens, energy is released and is used to form ATP and the rest is lost as heat . At the end of each system, the now low energy electron is removed by combining it with oxygen and hydrogen to form water.

Question 19

what is oxidative phosphorylation

Answer 19

the production of ATP by the electron transport system, as it requires oxygen and phosphate

Question 20

where does the electron transport system take place?

Answer 20

in the cristae of the mitochondria

Question 21

what is fermentation

Answer 21

anaerobic respiration is called fermentation… two types: lactic acid fermentation and alcohol fermentation

Question 22

what is lactic acid fermentation

Answer 22

occurs in some anaerobic bacteria, fungi and animal cells when there is not enough oxygen. glucose -> 2 lactic acid + small amout of energy

Question 23

describe alcohol fermentation

Answer 23

takes place in bacteria, some fungi and plants when they are deprived of oxygen. this involves the partial breakdown of glucose. glucose -> 2 ethanol + 2 carbon dioxide + small amount of energy

Question 24

how are micro-organisms used in bioprocessing

Answer 24

bacteria can be used to make yoghurts, antibiotics. yeast can be used to make beer + wine, fungi can produce antibiotics + citric acid

Question 25

experiment: to prepare and show the production of alcohol by yeast

Answer 25

1. dissolve 5g of glucose in 100cm^3 of water. 2. boil the solution in a conical flask for 5mins to elimiate gases + form anaerobic conditions. 3. when the solution cool, add a sachet (5G) of dried yeast. 4.cover the liquid with a thin layer of oil to prevent oxygen from entering. 5. add an airlock to the top of the conical flask with limewater. 6. Co2 produced will turn limewater cloudy/milky

Question 26

Explain how you tested for ethanol production

Answer 26

1. filter the solution to remove yeast cells. 2. add 3cm^3 of potassium iodide in a test tube. 3. add 3cm^3 of filtrate to the solution. 4. add 5cm^3 of sodium hypochlorite to the test tube. 5. warm the test tube gently in a water bath. 6. watch for pale yellow crystals being formed