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Question 1

How many carbons are there in the first 4 metabolites of the ‘upper’ Embden-Meyerhof (investment) pathway before aldolase?

Answer 1

6C, 6C, 6C, 6C

Question 2

What is the terminal electron acceptor in aerobic respiration?

Answer 2

Molecular oxygen only

Question 3

Here is an example of a half -reaction with its gibbs function. Give true statements about it.
3,5-dinitrosalicylic acid +e->3-amino-5-nitrosaliclic acid
=+30.9kj/mol DNS reduced

Answer 3

1. 3,5-dinitrosalicylic acid is being reduced
2. 3-amino-5-nitrosalicylic acid is more reduced than 3,5-dinitrosalicylic acid
3. It is not impossible to do this reaction physically as free electrons don’t exist in aqueous solution
4. The reaction is not thermodynamically favourable

Question 4

Fates of pyruvate produced in the glycolytic pathways in any organism?

Answer 4

1. Oxidation to ethanol and carbon dioxide in alcohol fermentation some fungi
2. The Swanson condensation and then Krebs cycle
3. Oxidation to butanol-1-ol, acetone and acetic acid in ABE fermentation in some bacteria
4. Oxidation to lactate in homolactic fermentation in the muscles of the mammalian

Question 5

What part of the NADP molecule is the electron carrier?

Answer 5

The nicotinamide moiety

Question 6

Functions of compartmentalisation of parts of a metabolic pathway?

Answer 6

1. To protect the rest of the cell from toxic intermediates
2. To stop some metabolites reacting with other enzymes when it is not wanted
3. To protect the cell from e.g: hydrolase enzymes that can cleave proteins and lipids
4. To raise the conc of some metabolites for some enzymes

Question 7

What is the difference between NADH and NADPH?

Answer 7

NADH is primarily used in catabolism; NADPH is primarily used in anabolism

Question 8

State the law of energy

Answer 8

Energy cannot be created nor destroyed ;only transformed from one form to another

Question 9

How many of the 6C of a hexose sugar has been lost by the end of Embden-Meyerhoff pathway to CO2

Answer 9

0C

Question 10

If a metabolic pathway can operate in the reverse direction, these things happen..

Answer 10

1. There will be some degree of commitment on the first steps on both directions
2. Most non-terminal steps will be common to both directions
3. Additional steps may be needed in the reverse direction
4. The first and last steps will be unique to each directionality

Question 11

Which part of the FAD molecule is the electron carrier?

Answer 11

The flavin moiety

Question 12

In central metabolism…

Answer 12

Catabolism generates ATP and NADPH; anabolism consumes ATP and NADPH

Question 13

What do FAD and NAD have in common?

Answer 13

Both FAD and NAD can carry 2 electrons

Question 14

What are the mechanisms by which ATP can be made from ADP?

Answer 14

Ion-gradient-coupled phosphorylation only and using sodium ions only

Question 15

What are the names of the 2 sectors of the proton-translocating 2-sector ATPase?

Answer 15

F1 hanging off the membrane and Fo within the membrane (that is the roman letter “O”)

Question 16

Statements about the ‘lower’ Embden-Meyerhoff (‘payoff’)

Answer 16

1.it contains one redox reaction
2. It is repeated twice, once for each G3P unit
3. It is often found as a metabolism in the eukarya
4. It produces 2NADH in toto

Question 17

Statement about respiratory chains and ATP biosynthesis in common pathogenic bacteria found in the gut of the mammalian…

Answer 17

They generate /use sodium-motive force, not proton-motive force

Question 18

What is the role of the link reaction?

Answer 18

To convert pyruvate to acetylene-CoA (and CO2), linking the gylcolytic pathways and Krebs’ cycle.

Question 19

What is the metabolic mode of an organism that uses the following;
Energy source: electromagnetic radiation
Electron donor: amino acids
Carbon source: amino acids
Terminal electron acceptor: sulfate

Answer 19

Anaerobic photoorganheterotroph

Question 20

Which statement about biochemical reaction coupling is not true?

Answer 20

Biochemical reaction coupling is 100% efficient and there are no losses

Question 21

Which statements about the Entner-Doudoroff pathway is false?

Answer 21

It is only found in the bacteria

Question 22

What is a common terminal electron acceptor used in anaerobic respiration by organisms living in marine sediment?

Answer 22

Sulfate