respiration

Question 1

importance of respiration for organisms

Answer 1

all organisms need to carry out respiration in order to make energy available in cells

Question 2

what is respiration (include example)

Answer 2

Respiration is a catabolic process involving a series of enzyme-catalysed reactions in cells.

Energy-rich respiratory substrates, such as glucose and fatty acids, are broken down to release energy.

Question 3

what happens to the energy

Answer 3

Some of the energy is transferred to chemical energy in ATP (adenosine triphosphate) and some is released as heat energy.

Question 4

what happens during respiration? (bonds, energy)

Answer 4

During respiration, high energy C-C, C-H and C-OH bonds are broken, lower energy bonds are formed, and the

remaining energy is released and used to attach inorganic phosphate to ADP (adenosine diphosphate) to make ATP.

Question 5

types of respiration

Answer 5

aerobic respiration

anaerobic respiration

Question 6

what is aerobic respiration

Answer 6

Aerobic respiration is when a glucose molecule is completely broken down to carbon dioxide and water in a series of reactions.

Question 7

stages in aerobic respiration

Answer 7

glycolysis

link reaction

Krebs cycle

electron transport chain

Question 8

where does glycolysis take place

Answer 8

in the cytosol

does not require o2

Question 9

3 stages of glycolysis

Answer 9

1. The phosphorylation of glucose. The hydrolysis of 2 ATP molecules provides the phosphate. The 6C hexose bisphosphate that is formed is unstable with a low activation energy.
2. The splitting of the 6C hexose bisphosphate formed into two 3C triose phosphate molecules.
3. The oxidation of each of triose phosphate to 3C pyruvate through the loss of hydrogen – this is through the action of a dehydrogenase enzyme. ATP is produced by substrate level phosphorylation in this process (2 ATP per triose phosphate).

Question 10

what does glycolysis produce?

Answer 10

-a net yield of 2 ATP produced by substrate level phosphorylation

-2 molecules of reduced NAD (also written as NADH2 and NADH + H+)

-2 pyruvates.

[NAD = nicotinamide adenine dinucleotide]

Question 11

where does link reaction take place?

Answer 11

matrix of mitochondria

Question 12

o2 involvement and link reaction

Answer 12

If oxygen is available, the pyruvate produced in the cytosol is actively transported into the matrix of the mitochondria.

Question 13

what does link reaction do

Answer 13

links glycolysis and Krebs cycle

Question 14

what does link reaction involve/ steps

Answer 14

3C pyruvate molecules are converted to 2C acetate (C2H5-) through the loss of a carbon dioxide (in modern Chemistry acetate is called ethyl but we still use acetate in this context)

carbon dioxide is produced through the action of a decarboxylase enzyme

hydrogen is lost through the action of a dehydrogenase enzyme

NAD is reduced by the hydrogen to NADH2

acetate is activated by combining with co-enzyme A to produce acetyl co-enzyme A.

Question 15

What enters the Krebs cycle and where does it take place?

Answer 15

Each acetyl co-enzyme A enters the Krebs cycle, which takes place in the matrix of mitochondria.

Question 16

what is the Krebs cycle

Answer 16

The Krebs cycle is a series of decarboxylation and dehydrogenation reactions. It is a means of liberating energy from bonds to provide ATP and reduced NAD (as well as reduced FAD).