K.C.S.E Biology Q & A - MODEL 2009PP1QN04
The state during which a seed cannot germinate even when conditions for Germination are suitable is called
ANSWER
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K.C.S.E Biology Q & A - MODEL 2008PP1QN21
What is seed dormancy
ANSWER
K.C.S.E Biology Q & A - MODEL 2008PP1QN17
Account for the following phases of a sigmoid curve of a growth of an organism
(a) Lag phase (b) Plateau phase
ANSWERS
(a) Few dividing cells/ cells not adjusted to surrounding environment
(b) Most cells fully differentiated/ rate of cell division equals rate of cells dying K.C.S.E Biology Q & A - MODEL 2008PP1QN01
Name the tissues in plants responsible for:
(a) Transport of water and mineral salts (b) Transport of carbohydrates (c) Primary growth
ANSWERS
(a) xylem
(b) Phloem (c) Apical meristems
K.C.S.E Biology Q & A - MODEL 2007PP1QN23
Name the hormone that is responsible for apical dominance
ANSWER
K.C.S.E Biology Q & A - MODEL 2007PP1QN19
Name the part of a bean that elongates to bring about epigeal germination
ANSWER
K.C.S.E Biology Q & A - MODEL 2007PP1QN19
State two environmental conditions that can cause seed dormancy
ANSWERS
K.C.S.E Biology Q & A - MODEL 2006PP2QN06
An experiment was carried out to investigate the effect of hormones on growth of lateral buds of three pea plants
The shoots were treated as follows: Shoot A – Apical bud was removed. Shoot B – Apical bud was removed and gibberellic acid placed on the cut shoot. Shoot C – Apical bud was left intact. The length of the branches developing from lateral buds were determined at regular intervals. The results obtained are as shown in the table below.
a) Using the same axes, draw graphs to show the lengths of branches against time.
b)i) What was the length of the branch in shoot B on the 7th day? ii) What would be the expected length of the branch developing from shoot A on the 11th day? c) Account for the results Obtained in the experiment d) Why was shoot C included in the Experiment? e) What is the importance of gibberellic acid in agriculture? f) State two physiological processes that are brought about by the application of gibberellic acid on plants.
answers
(b) (i) 105 + 1 (mm)
(ii) 134 – 140 (mm) (c) Graph A: The tip of the shoot which was removed contained indole acetic acid (IAA); which causes apical dominance/ inhibits growth/ development of more lateral buds; hence lateral buds sprouted/grew. Graph B; the gibberellic acid which was added on the cut. Promotes formation of lateral branches of stems, hence the fast growth of branches on shoot b. Graph C; The shoot tip which remained intact contains IAA which inhibits growth/ development of lateral buds; hence little change of length of lateral branches. (d) Control (e) Increase productivity (f) Promote cell division, and cell elongation
K.C.S.E Biology Q & A - MODEL 2006PP1QN14
Why is oxygen necessary in the germination of seeds?
answer
K.C.S.E Biology Q & A - MODEL 2006PP1QN14
Distinguish between epigeal and hypogeal germination.
answers
​K.C.S.E Biology Q & A - MODEL 2005PP1QN08
Name three factors in seeds that cause dormancy.
answers
K.C.S.E Biology Q & A - MODEL 2004PP1QN17
During germination and growth of a cereal, the dry weight of endosperm, the embryo and total dry weight were determined at two – day intervals. The results are shown in the table below.
a) Using the same axes, draw graphs of dry weigh of endosperm, embryo and the total dry weight against time
b) What is the total dry weight on day 5? c) Account for: i) Decrease in dry weight of endosperm from day 0 to 10 ii) Increase in dry weight of embryo from day 0 day 10 iii) Decrease in total dry weight from day 0 to day 8 iv) Increase in total dry weight after day 8 d)Dormancy. i) Within a seed ii) Outside the seed e) Give two characteristics of meristematic cells
answers
​(b) 38.5 (mg); Acc. + 0.5 ( i.e. 38 – 39)
(c) (i) Hydrolysis of starch into simple sugars; which are translocated to the embryo; Respiration/ to give energy/ heat/ gases Acc. Simple sugar oxidized (ii) New materials are synthesized from protein); bringing about growth of embryo; acc new cells/ protoplasm synthesized (iii) The rate of respiration is faster than that of synthesis of materials for growth (iv) First leaf (carried out photosynthesis) leading to growth (d) (i) Presence of absiscic acid/ germination inhibitors; Embryo not fully developed Absence of hormones/ enzymes that stimulate germination Impermeable seed coat; rej hard seed coat Acc. Inactive enzymes/ hormones/ absence of gibberellins/ cytokinins. (ii) – Unsuitable / unfavourable temperature - absence of light - lack of water - lack of oxygen (c) Dense cytoplasm - Thin cell wall - Absence of vacuoles ( cell sap) K.C.S.E Biology Q & A - MODEL 2003PP1QN07
The diagram below represents regions of a root tip.
a) Name the tow regions above X in ascending order
b) State the function of the part labeled X
answers
a) Zone of cell division Acc cell multiplication
Zone of cell elongation / enlargement; Acc expansion for elongation b) To protect root tip
K.C.S.E Biology Q & A - MODEL 2002PP1QN19
Describe the role of hormones in the growth and development of plants.
answers
Indole acetic acid/IAA/ Auxins
K.C.S.E Biology Q & A - MODEL 2002PP1QN04
During germination and early growth, the day weight of the endosperm decreases while that of the embryo increases. Explain.
answers
K.C.S.E Biology Q & A - MODEL 2000PP1QN19
How are leaves of mesophytes suited to their functions
answers
​Broad/ wide/ flat lamina provides large surface area for absorption of (O) and sunlight, thin to ensure short distance of CO2 reach photosynthesis/ palisade cells; presence of stomata guard cells for efficient diffusion of O2 gaseous exchange / H2O vapour transpiration/ CO2 into the leaf transparent cuticle epidermal cells; for light penetration into palisade cell which contains chloroplast next to upper epidermis; these receives maximum light for photosynthesis. Chloroplasts have chlorophyll, which traps light energy.
Leaves have vein, xylem and phloem to transport products of photosynthesis to other part of the plant. Air spaces on spongy mesopyll, easily circulates gases/ CO2 diffuse into palisade cells. Mosaic arrangements of leaves; enable leaves to trap sunlight. K.C.S.E Biology Q & A - MODEL 1999PP1QN12
A student set up an experiment as shown in the diagram below..
a) i) What is being investigated in the experiment?
ii) On the diagram below indicate the expected results after three days.
​iii) Why was it necessary to have wet cotton wool in the containe?
b) What is the role of the following to a germinating seed/ i) Oxygen ii) Cotyledons.
answers
​.a) i) Region of elongation (rapid) growth in a root.
b) i) Oxygen
Oxidation of stored food; to provide energy (for germination) ii) Cotyledons Store food necessary for germination; protecting the plumule. State three ways by which plants compensate for lack of ability to move from one place to another.15/6/2020
K.C.S.E Biology Q & A - MODEL 1999PP1QN06
State three ways by which plants compensate for lack of ability to move from one place to another.
answers
K.C.S.E Biology Q & A - MODEL 1998PP1QN08
A flower was found to have the following characteristics:
Inconspicuous petals Long feathery stigma Small, light pollen grains (a) What is the likely agent of pollination of the flower (b) What is the significance of the long feathery stigma in the flower?
ANSWERS
(a) wind
(b) To enable it trap pollen grains in the air; reject catch/ attach for trap K.C.S.E Biology Q & A - MODEL 1997PP1QN18
An experiment was carried out to determine the growth rates of bamboo and a variety of maize plants in two adjacent plots. The average height and average dry weight of plants from the two populations were determined over a period of twenty weeks. The data is as shown in the table below.
(a) Between which two weeks did the greatest increase in weight occur in
(b) Bamboo plants (ii) Maize plants (b) (i) Which of the two types of plants had a higher productivity by the end of the experiment (ii) Give a reason for your answer in (b) (i) above (c) Between weeks 14 and 18, the average height of the maize plants remained constant while average dry weight increased. Explain this observation (d) Suggest how the change in the average dry weight bamboo and maize Plants would have been at week 22 if the experiment was continued. (e) Why was it appropriate for this experiment to use (i) Dry weight instead of fresh weight (ii) Weight and height (f) Describe how the average height and weight of the plants were determined in this experiment. Average height Average dry Weight (g) Give a reason why secondary thickening does not occur in bamboo and maize plants
answers
(a) (i) Bamboo plants
4 and 6 (ii)Maize plants 12 and 14 (b) (i) Bamboo (ii) It had accumulated more weight and therefore greater dry weight (c) Maize plants have reached maturity/maximum height food being manufactured (in green parts); is utilized for growth storage primary in the cob. (d)Increase in weight – bamboo reject both increase/ decrease accept bamboo and maize increase/ decrease. (e) (i) Dry weight instead of fresh weight Fresh weight is dependant on the amount of water present in the plants and this fluctuates depending on environmental factors. (ii) Weight and height Both given a better measure of growth (f) Average height At every 2 weeks measure the height of samples of plants in each plot: Divide the total height by the number of plants in each of plot. Average dry weight Harvest the sample measure of the plants in each plot; dry to constant weight: And divide by the number of plants (g) Being monocots/ lack (Inter) fascicular cambium: The graph below represents the increase in the number of yeast cells over a period of 48 minute:
KNEC ANSWERS
(g)
(h)
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