B3.5 Factors affecting enzyme action

Question 1

describe the effects of temperature on an enzyme-controlled reaction.

Answer 1

Rate of enzyme‑controlled reaction initially increases as temperature
increases, up to optimum temperature.
Once temperature exceeds 40 °C, protein structure of enzyme starts to
break down.
Rate of reaction slows and ultimately stops when enzyme is denatured
(stops working)

Question 2

Explain the effect of temperature and PH on enzyme action

Answer 2

Both change shape of active site
both change rate of enzyme‑controlled reaction and ultimately stop it.
Temperature permanently denatures most enzymes over about 40 °C.
Different enzymes work best at different pH levels.

Question 3

when you get an infectious disease you may get temperature ; this is a way your body defends you as many microorganisms cannot reproduce at high temperatures. However, people always try to bring the temperature of an ill person down. Explain why this may be the case.

Answer 3

If body temperature increases too much (e.g., over 40 °C), proteins
making up cell structure start to be damaged and shape of protein
molecules making up enzymes is affected.
This changes shape of active sites
making enzymes less effective and ultimately denaturing them,
preventing chemical reactions necessary for life.
Reducing temperature in ill person represents balancing act between
damaging harmful microorganisms and damaging ill person’s own cells