CELL PHYSIOLOGY

Explain each of the following physiological observations:
(a) sportsmen release little, concentrated urine at the end of a strenuous exercise 
(b) a rabbit has a higher oxygen demand than a camel 

In investigating a certain physiological process, students set up the apparatus as shown below and made the observations after 30 minutes as illustrated.

​(a) Name the physiological process being investigated.
(b) Account for the observation made at the end of the experiment. 
(c) State the likely identity of G. 

A group of form two students placed a fresh leaf in warm water. They observed that air bubbles formed on the surface of the leaf.
(a) What biological process were they investigating? 
(b) Name the structures from which the air bubbles were coming from.
(c) Explain the distribution of the structures named in (b) above on the leaf surfaces of a land plant.

The photograph below represents a leaf obtained from a certain plant.

​Account for the observations made if the leaf was tested for starch.

K.C.S.E Biology Q & A - MODEL 2017PP1QN15

 The set up below illustrates a certain physiological process.

​(a) (i) Name the physiological process. 
(ii) Give two examples of the process named in (a) (i) above in plants. 
(b) State two ways by which the movement of dye molecules in the set up would be slowed down.

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.

A freshly obtained dandelion stem measuring 5cm long was split lengthwise to obtain two similar pieces. The pieces were placed in two different solutions of different concentrations in petri dishes (L1 and L2) for 20 minutes. The appearance after 20 minutes is as shown.

​(a) Account for the appearance of the pieces in solutions L1 and L2 
(b) Suite the significance of the biological process involved in the experiment.

K.C.S.E Biology Q & A - MODEL 2016PP1QN25

K.C.S.E Biology Q & A - MODEL 2016PP1QN018

Students set up an experiment as illustrated below.

​(a) Name the physiological process that resulted in the observations made after 30 minutes.
(b) State the importance of the physiological process investigated in plants. 
(c) Explain the observations made after 30 minutes.

What is meant by each of the following terms?
(i) Crenated cell. 
(ii) Flaccid cell.

K.C.S.E Biology Q & A - MODEL 2014PP1QN10

The diagram below shows a set up for an experiment to demonstrate a certain physiological process.

​(a) What nature of solution is represented by 20% sugar solution? 
(b) Explain the observation made on the set up after one hour.