Cellular respiration

Question 1

What is metabolism

Answer 1

Describes collection of all chemical reactions that occur in the body

Question 2

What is anabolism

Answer 2

It is to build

I.e. synthesis of glycogen from glucose or synthesis of peptides from amino acids

Question 3

What is catabolism

Answer 3

It is to destroy (breaking large molecules into smaller ones)

I.e. Cellular respiration - oxidation of glucose and CO2

Breakdown of proteins to peptides

Question 4

What are the energy carriers in the body

Answer 4

ATP and it acts like a rechargable battery.

ATP –> ADP + Pi (free phosphate)

This could also reverse

Question 5

What are some features of ATP

Answer 5

ATP can’t be stored

It can be generated in presence (aerobic respiration) or absence of oxygen (anaerobic respiration)

Question 6

What are some examples of uses of ATP

Answer 6

ATP is used for the active transport of molecules across cell membranes (i.e. Na K+ pump)

Contraction of muscles

Synthesising hormones, cell membranes other essential molecules

Cell division and growth

Question 7

What does cellular respiration involve a series of

Answer 7

Involves a series of oxidation-reduction reactions

Question 8

What does oxidisation mean

Answer 8

Involves the loss of electrons (i.e. loss of a hydrogen)

Glucose being oxidised to carbon

Question 9

What does reduction mean

Answer 9

Involves the gain of an electron (i.e. addition of a hydrogen)

O2 being reduced to water

Question 10

What are some other energy carriers which are involved in the process of cellular respiration other than ATP

Answer 10

nicotinamide adenine dinucleotide (NAD) - It is NADH in its reduced form, and carries electrons and is a good electron donor. NAD+ (oxidised form) - not carrying electrons and is a good electron acceptor

Flavin adenine dinucleotide (FAD) - It is FADH2 in its reduced form, and carries electrons and is a good electron donor. FAD is the oxidised form and doesn’t carry electrons but is a good electron acceptor

Question 11

What are the 4 cellular respiration pathways which occur in order

Answer 11

Glycolysis

Intermediate reaction (doesn’t directly use O2)

Krebs cycle (doesn’t directly use O2)

Electron transport chain (uses oxygen)

Question 12

Explain the process of glycolysis. What is produced and how much of it. What are the requirements of it

Answer 12

It is a series of 10 reactions in the cytosol that produces 2 pyruvate molecules from 1 glucose molecule

Doesn’t use oxygen and occurs regardless of whether O2 is present or not

Produces 4 ATP molecules overall, however it has a net gain of 2 ATP (uses 2 ATP somewhere in the process), before 4 ADP is turned into 4 ATP

NAD+ picks up electron and is reduced to NADH. Thus, two NADH at the end

Thus gain of 2 ATP, 2 NADH and 2 pyruvate moleules per glucose molecule

Question 13

Explain the intermediate reaction. What is produced and how much of it. What is the requirements of it

Answer 13

This involves the conversion of pyruvate produced from glycolysis into acetyl CoA. Electrons are removed, and given to NADH electron basket

Overall, 2 NADH and 2 acetyl CoA is produced from the two glucose molecules (i.e. 1 NADH and 1 acetyl CoA per glucose molecule)

Question 14

Explain the Krebs cycle. What is produced and how much of it. What are the requirements of it

Answer 14

Series of 8 reactions in the mitochondrial matrix.

For every acetyl CoA taking part, products are 2 x CO2, 3x NADH, one FADH2, one ATP

Overall, if the two acetyl CoA come in from the two pyruvate molecules of a glucose molecule, it creates 6x NADH, 4 x CO2, 2 FADH2, two ATP

Question 15

What is the function of NADH and FADH2

Answer 15

It is to carry electrons which are going to be used for the electron transport chain

Question 16

Explain the electron transport chain. What is produced and how much of it. What are the requirements for it

Answer 16

Basically the previous electron carriers (NADH and FADH2) oxidise in the matrix, thus turning into NAD+ and FAD. As a result of this, electrons are deposited in one (of four) protein complexes, which assists in bringing the H+ from the matrix to the intermembrane space. As such, the intermembrane space has an extremely high concentration of H+ (protons) from the deposition of the four protein complexes. These e- are then used to react with oxygen and H+ in the matrix to produce H2O.

The creation of ATP occurs with the ATP synthase which allows for H+ to flow through it (via the electrochemical gradient of protons), to ultimately free phosphate and turn ADP to ATP, ultimately producing ATP

This process creates 28-34 ATP per glucose oxidised

Question 17

What is efficiency considered as

Answer 17

Refers to amount of ATP produced per molecule of glucose

Question 18

Compare glycolysis and aerobic respiration

Answer 18

Glycolysis is faster, but only produces a net of 2 ATP per glucose molecule

However, electron transport chain takes longer but produces 28-34 molecules per glucose molecule

Question 19

How many atp molecules produced for every NADH

Answer 19

3 ATP molecules

Question 20

How many atp molecules produced for every FADH2

Answer 20

2 ATP molecules

Question 21

Explain atp as a currency of a cell

Answer 21

It is used as a currency of the cell such as:

active transport of molecules across cell membrane

contraction of muscles

synthesising hormones, cell membranes and other essential molecules

cell division and growth

Question 22

Explain atp as a coin between catabolism and anabolism