Cell Respiration . . .

... check your knowledge in (fairly) easy stages.

1. Basics about cell respiration
2. Going deeper with glycolysis
3. The Krebs Cycle
4. The Electron Transfer Chain

Marks are shown in brackets. The marking point in the answers are separated by ; . The / denotes an acceptable alternative wording. If unsure about anything and you can't work it out from your textbook email me!

1. What is cell or tissue respiration? (2 )
2. What other way is the term 'respiration' commonly understood? (1)
3. What is the connection between your answers to 1 and 2? (2)
4. Cell respiration results in energy being stored in a short term chemical substance called? (1)
5. What is the substance you have named in 4 synthesised from or converted to? (1)
6. Give an overall word equation for aerobic cell respiration. (1)
7. Name the FOUR key stages of cell respiration. (4)
8. What are the useful end products of the first stage? (2)
9. How much of these products is produced? (2)
10. What name is given to respiration when oxygen is absent? (1)
11. What end products are possible from this type of respiration a)in animals and b) yeast? (2)
12. What name is given to respiration when oxygen is present? (1)

1. The breakdown/oxidation of glucose to release energy;


It may occur in the presence or absence of oxygen;

2. Breathing- commonly called (whole) body respiration;
3. Body respiration supplies the oxygen;

and removes the carbon dioxide; used in cell respiration

4. Adenosine Triphosphate (ATP will usually be OK!);
5. Adenosine Diphosphate (ADP);
6. GLUCOSE + OXYGEN à ENERGY + WATER + CARBON DIOXIDE (if you said ATP instead of energy, that is fine!);
7. Glycolysis; Link Reaction; Krebs/TCA/Citric acid Cycle; Electron Transfer Chain/Oxidative phosphorylation;
8. Pyruvate/Pyruvic Acid; (both are usually acceptable) ATP;
9. 2 pyruvates; 4 ATP's but 2 ATP's simply repay that used to start the whole thing rolling, making a NET product of 2 ATP's;
10. Anaerobic respiration;
11. Animals- Lactic Acid/Lactate; Yeast- Alcohol/Ethanol; (NOT ethanal) which is an intermediate substance).
12. Aerobic Respiration;

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Respiration 2 - Going deeper with glycolysis

1. Remind me- what is produced (and how much) at the end of glycolysis? (3)
2. How many carbons are there in the original glucose molecule? (1)
3. How is the substance triose phosphate produced during glycolysis?(1)
4. What is another name (and abbreviation) for triose phosphate? (2)
5. Triose phosphate is then 'oxidised' to form another 3-carbon substance before we get to pyruvate.(for A level we only need to note one-though there are several!) Name the substance and give its abbreviation. (2)
6. What gaseous substance is produced by the oxidation of GALP? (1)
7. Name the substance that 'mops up' your answer to 6. Which vitamin is vital for this substance to be present?(2)
8. Name the process whereby the glucose molecule's activation energy is overcome. (1)
9. What does your answer to 9 actually mean in chemical terms? (2)
10. When during glycolysis, is ATP formed? (2)
11. Where in the cell does glycolysis happen? (1)
12. How much ATP do you think there is in the human body- 1g, 5g, 50g, 500g, 1kg? What are the implications of this? (2)

20- excellent. Carry on to the next quiz-'Going deeper with Hans'

Below 15 - keep going over the questions, writing your answers down, until you get 20!

1. 2 molecules of ATP (NET); and 2 molecules of pyruvate; from one molecule of glucose;
2. Six - it is shown as 6C;
3. By splitting the original 6C glucose into two 3 carbon molecules of triose phosphate;
4. Glyceraldehyde-3-phosphate; or GALP; (note the '3-phosphate' part of GALP is where the name 'triose phosphate' comes from. In other words it has 3 (tri) phosphates.)
5. Glycerate-3-phosphate; GP;
6. Hydrogen;
7. NAD⁺ (becomes NADH); NAD (nicotinamide adenine dinucleotide) is derived from the B vitamin nicotinic acid; check if you need to know about this vitamin in your human biology units-remember synoptic questions!
8. Phosphorylation;
9. A phosphate molecule is added to the glucose molecule; it is derived from ATP; (which now becomes ADP due to the loss of one phosphate)
10. During the conversion of GALP to GP; and during the conversion of GP to pyruvate;
11. Cytosol; (you may get away with 'cytoplasm'-though this really refers to everything, including organelles, that is between the nucleus and cell surface membrane).
12. Around 50g;. You may not be directly asked this, but it follows that as we use about 140kg of ATP daily there must be an incredible rate of turnover, breakdown and regeneration! ATP really is a 'short-term energy store'. It's an important principle to remember.

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1. During aerobic respiration, where does the pyruvate go after glycolysis? (1)
2. What substance does it combine with? (1)
3. When the pyruvate combines with the substance named in answer 2; what two substances are produced? (2)
4. "acetyl CoA combines with .............. .............. to form .............. .............. "(2)
5. Which two substances 'mop up' the hydrogen produced during the Krebs Cycle? (1)
6. Precisely where in the cell does the Krebs Cycle take place?(1)
7. The hydrogen atoms are the ................ power for the ETC (1)
8. Where is most of the ATP produced (precisely) during respiration? (1)

10- excellent. Carry on to the next quiz-"Electron Transfer"

6-9 recheck your weak areas before carrying on to the next quiz.

5 or less - keep going over the questions, writing your answers down, until you get 10!

1. It enters the mitochondria;
2. Acetyl co-enzyme A ( or acetyl CoA);
3. Carbon dioxide; and hydrogen;
4. "acetyl CoA combines with oxaloacetic acid to form citric acid "
5. NAD and FAD;
6. Matrix of the mitochondria;
7. Reducing;
8. On the stalked particles;

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Fill in the blanks.

The ........................ attached to NAD and ........................ is transferred to a number of ........................ containing ........................ carriers called ......................... In the process the atoms of ........................ are split into protons and ......................... The former are not passed along the carriers but eventually recombine with ........................ to form .........................

The negatively charged ........................ however ARE passed from carrier to carrier, alternately ........................ and ........................ them.

As this happens, energy is released at each stage and is used to power ........................ pumping. This process works as follows.

The energy released at each stage of the transfer chain is used to pump ........................ across the ........................ ........................ into the ........................ ......................... This creates a pH gradient as well as a ........................ difference. The result is that ........................ diffuse back into the mitochondrion (probably via the ........................ particles).

As this diffusion occurs, the enzyme ........................ ........................ is activated resulting in the formation of the substance ........................

You need to score 22!

The HYDROGEN attached to NAD and FAD is transferred to a number of IRON containing PROTEIN carriers called CYTOCHROMES. In the process the atoms of HYDROGEN are split into protons and ELECTRONS. The former are not passed along the carriers but eventually recombine with OXYGEN to form WATER.

The negatively charged ELECTRONS however are passed from carrier to carrier, alternately OXIDISING and REDUCING them.

As this happens, energy is released at each stage and is used to power PROTON pumping. This process works as follows.

The energy released at each stage of the transfer chain is used to pump PROTONS across the INNER MEMBRANE into the INTERMEMBRANE SPACE. This creates a pH gradient as well as a POTENTIAL difference. The result is that PROTONS diffuse back into the mitochondrion (via the STALKED particles).

As this diffusion occurs, the enzyme ATP SYNTHETASE is activated resulting in the formation of the substance ATP.

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