C1.2.4—Cell respiration system

The need for energy

a. life processes/active transport/metabolism/movement require energy;

b. ATP provides energy for cell processes;

c. energy need to break bonds in a substrate during enzyme reactions;

d. energy is required to synthesize ATP from ADP

OR

energy is released when ATP is hydrolysed;

Release of energy

e. cell respiration produces ATP using energy stored in carbon compounds/glucose/fatty acids;

f. aerobic respiration occurs in mitochondria;

g. aerobic respiration requires oxygen;

h. aerobic respiration provides more ATP/energy than anaerobic respiration;

i. cells use mainly glucose and/or fatty acids as a fuel/substrate for respiration;

j. in aerobic respiration carbon dioxide and water are waste products

OR
$$\text { fuel/glucose }+\mathrm{O}_{2} \rightarrow \mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \text { (+ energy/ATP); }$$

k. anaerobic respiration (in humans) yields lactic acid as a waste product

OR

fuel/glucose → lactic acid (+ energy/ATP);

Correct equation can gain
marking points g. and j.
Equation does not need to be balanced.

8

Marking guidance:

max