K.C.S.E Biology Q & A - MODEL 2016PP2QN06

K.C.S.E Biology Q & A - MODEL 2016PP2QN06

An experiment was carried out to investigate the effect of temperature on the rate of reaction catalysed by an enzyme. The results are shown in the table below.

​(a) On the grid provided plot the rate of reaction against temperature. 
(b) When was the rate of reaction 2.6 mg of product per unit time? 
(c) Account for the shape of the graph between:
(i) 5°C and 40°C 
(ii) 45°C and 60°C 
(d) Other than temperature name two ways in which the rate of reaction between 5°C and 40°C could be increased.
(e)(i) Name one digestive enzyme in the human body which works best in acidic condition. 
(ii) how is the acidic condition for the enzyme named in (e) (I) above attained’? 
(f) The acidic condition in (e) (iii) above is later neutralized.
(i) Where does the neutralization take place? 
(ii) Name the substance responsible for the neutralization.

answers

​(b) 330C and 51.5 (± 0.50C)
 32.5 - 33.5 and 51.0 – 52.0
(c) (i) 5°C and 40° C 
 As temperature is increased rate of reaction is increased/ more products are formed (per unit time) because enzymes become more active
(ii) 45° C and 60° C 
 As temperature increase rate of reaction decreases less/products are formed (unit per time) because enzymes become denatured by high temperatures above 40, hence cannot act on substrate.
(d)  Increase in enzyme and substance concentration
 Use of co-factors and co-enzymes
(e) (i)  Pepsin,
 Chymosin
 Renin
(ii)  Wall of stomach/ gastric gland/ oxyntic/ pariental/ cell produced Hydrochloric
(f) (i)  Duodenum
(ii)  Bile juice/ e.g. NaHCO3