Respiration

Question 0

How did you test for the presence of alcohol?

Answer 0

• Filter solution in the flask
• Add potassium iodide and sodium hypochlorite to a sample of filtered solution
• This will turn brown/orange colour
• place test tube in hot water bath
• the appearance of yellow crystals indicates alcohol is present

Question 1

Give two advantages of using immobilised yeast cells in the production of alcohol.

Answer 1

cheap
easy seperate from solution
reusable

Question 2

Explain the term METABOLISM.

Answer 2

Metabolism is the sum of all chemical reactions that take place within an organism. There are catabolic and anabolic reactions.
Catabolic reactios break down complex molecules to simpler forms.

Question 3

Write a note on the KREBS CYCLE.

Answer 3

Occurs in the 2nd stage of aerobic respiration in mitochondria. Starts with Acetyl CoA.
ADP is converted to ATP.

Question 4

Write something about ADP.

Answer 4

Adenosin Di Phosphate

low energy molecule made of the base adenine - a 5 carbon sugar called ribose and two phosphate groups.

Question 5

Cellular respiration may occur in one stage or two stages.

Give two differences, other than location, between Stage 1 and Stage 2.

Answer 5

Stage 1 - anaerobic

Stage 2 - produces small amount of energy

Question 6

Where in the cell does Stage 1 occur?

Answer 6

Cytosol

Question 7

What term is used to describe respiration in which only stage 1 occurs?

Answer 7

anaerobic respiration

Question 8

Name a chemical end product of anaerobic respiration.

Answer 8

lactic acid or ethanol

Question 9

In stage 2 of respiration electrons pass along an electron transport chain, releasing energy. In what molecule is this energy stored in the cell?

Answer 9

ATP

Question 10

To what are the electrons transferred at the end of the electron transport chain?

Answer 10

They combine with oxygen and hydrogen to form water.

Question 11

What name is given to the first stage of respiration?

Answer 11

Glycolisis

Question 12

The first stage ends with the formatio of pyruvate acid. In anaerobic conditions, what is produced from this pyruvate:

1) In muscle cells?
2) In yeast cells?

Answer 12

1) lactic acid

2) ethanol and Co2

Question 13

If conditions are aerobic, pyruvate next passes to an organelle in which the second stage of respiration takes place. Name this organelle.

Answer 13

Mitochondrium

Question 14

In the mitochondrium pyruvate is broken down to Co2 and two-carbon compound. Name this two-carbon compound.

Answer 14

Acetyl CoA

Question 15

The two-carbon compound (Acetyl CoA) passes directly into a series of reactions in the second stage of respiration. Name series of reactions and give one product.

Answer 15

Krebscycle- Carbon dioxide and water

Question 16

The electrons released from the above reactions pass along a transport chain and in the process energy is released.

1) To what use is this energy put?
2) At the end of the transport chain, what happens to the electrons?

Answer 16

1) to form ATP

2) electrons combine with protons