K.C.S.E Biology Q & A - MODEL 2018PP2QN06
The effect of auxin concentration on growth response of two parts of a plant, X and Y was investigated over a period of time. The results were tabulated as shown in the table below.
(a) On the same axis, draw line graphs of the effect on growth of the two parts, X and Y (percentage inhibition or stimulation) against the concentration
(b) With reasons, name the two parts of the plant, X and Y.
(c) From the graph identify: .
(i) the point at which the percentage stimulation was the same for both X and Y.
(ii) the optimum concentration of auxins required for part Y
(d) State three ways in which the effects of auxins on plants is applied in flower farming.
(e) Distinguish between simple and conditioned reflex action
Low auxin concentration stimulates (rapid/faster) cell division and elongation/growth in roots;
High concentration of auxins inhibits growth in roots;
Low auxin concentration has little effect on the growth of shoots/shoots are stimulated to grow with high auxin concentration (up to a given optimum);
c) i. 33%±2;
ii. 1.0 parts per million;
(d)Faster maturity of flowers/earlier flower formation/flowering;
Prunning/decapitating shoot tips to allow sprouting of lateral buds, hence more yield;
Keeping flowers fresh;
Stimulate formation/development of (adventitious) roots;
K.C.S.E Biology Q & A - MODEL 2018PP1QN23
State two characteristics of living things illustrated in the photograph below.
K.C.S.E Biology Q & A - MODEL 2018PP1QN14
The diagram below illustrates a germinating seedling.
(a) Name the type of germination illustrated in the diagram
(b) Describe how the type of germination named in (a) above is brought about.
(b) Hypocotyl elongates faster than the epicotyl; pushing cotyledons above the ground;
K.C.S.E Biology Q & A - MODEL 2017PP1QN14
The photograph below illustrates a germinating seedling.
(a) Name the type of germination illustrated in the photograph.
(b) Explain the function of each of the parts labelled G and H.
b. G- Elongates to expose the foliage leaves to light photosynthesis
H- Stores food (for growth);
For photosynthesis (it is green);
Protects plumule during germination;
K.C.S.E Biology Q & A - MODEL 2017PP1QN05
The photograph illustrates a housefly at various stages of its development.
(a) (i) On the photograph, name the stages of the life cycle.
(ii) Using arrows, link the stages of the life cycle in the correct order.
(b) (i) State two differences between the life cycles of a housefly and that of a cockroach.
(ii) State one advantage of the life cycle of a cockroach to itself.
K.C.S.E Biology Q & A - MODEL 2016PP1QN15
What is seed dormancy
K.C.S.E Biology Q & A - MODEL 2015PP1QN19
(a) Using the axes provided below, sketch a curve to illustrate the growth pattern observed in the phylum arthropoda.
(b) Explain the growth pattern observed observed in arthropods.
K.C.S.E Biology Q & A - MODEL 2015PP1QN18
The diagram below shows an experimental set-up to investigate the conditions necessary for germination. Test tube P was placed in a refrigerator while Q was left at room temperature. The set-ups were observed regularly for two weeks but no germination occurred.
Explain the observations in P and Q.
P - the low temperature/freezing temperature inactivated enzymes;
Q - Boiling eliminated oxygen; oil layer prevented entry of oxygen necessary for respiration during growth;
K.C.S.E Biology Q & A - MODEL 2014PP1QN02
What is meant by the term seed dormancy?
K.C.S.E Biology Q & A - MODEL 2013PP1QN19
State three factors in seeds that cause dormancy.
K.C.S.E Biology Q & A - MODEL 2012PP1QN25
State the role of the following hormones in the life cycle of insects:
ecdysone hormone; .
K.C.S.E Biology Q & A - MODEL 2012PP1QN24
State four characteristics of apical meristem cells.
K.C.S.E Biology Q & A - MODEL 2012PP1QN20
State three aspects that can be used to estimate growth in seedlings