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
(c) Apical meristems
K.C.S.E Biology Q & A - MODEL 2007PP1QN09
State two ways in which the root hairs are adapted to their function
K.C.S.E Biology Q & A - MODEL 2006PP2QN08
Describe how water moves from the soil to the leaves in a tree.
Water exists as a thin film in the soil between soil particles. The concentration cell sap is greater than that of the surrounding solution in the soil; Thus drawing water molecules across the cell wall and membrane into the root hair cells; by osmosis; water drawn into the root hair cell dilutes the cell sap/ makes it less concentration than that in the adjacent cell into the cortex cells. (By osmosis); across the endosperm by active transport; into the xylem vessels (of the root); Then conduct the water up into the xylem (vessels) of the stem; into xylem of leaves. Water is pushed/ rises up the stem by root pressure ( in the xylem vessels) water would rise by capillary; cohesion, and adhesive forces; water moves as a continuous an uninterrupted water column in the xylem (vessel) up the tree to the leaves. As water vaporizes from the spongy mesophyll cells; their cells sap becomes more concentrated than adjacent water flows into the cells from other surroundings cells; which in turn takes in water from xylem vessels within the leaf veins. This creates a pull / suction force/ transpiration pull that pulls a stream of water from xylem vessel in the stem and roots; the transpiration pull maintains continuous column of water from the roots into the leaves (transpiration stream).
K.C.S.E Biology Q & A - MODEL 2006PP2QN04
The diagram below represents a traverse section through a plant organ
A. From which plant organ was the section obtained?
B. Give two reasons for your answer in (a) above.
C. Name the parts labeled J,K and L.
D. State two functions of the part labeled M.
(b) Presence of root hairs
Presence of endodermis
Xylem star shaped at centre
Phloem at arms of the xylem
(c) J- Epidermis
L – Xylem
(d) - Absorption of water
Absorption of minerals salts
K.C.S.E Biology Q & A - MODEL 2006PP1QN03
Name two tissues in plants which are thickened with lignin.
K.C.S.E Biology Q & A - MODEL 2005PP1QN14
A set up that was used to investigate certain process in plants is shown in the diagram below.
a) What process was being investigated?
b) (i) State two precautions that should be taken when setting up the experiment.
(ii) Give a reason for each precaution stated in b(i) above.
c) State three environmental factors that influence the process Under investigation.
b)i) The leafy shoot should be from herbaceous plant
Cut off the last few centimeters of the stalk under water
All the air in the capillary tubule should be expelled
Jelly should be applied around the stem around the rubber bung.
The end of the capillary fusing should rest in beaker of water.
ii) Avoid air bubbles.
For continuity of the flow of water
Jelly should not touch the xylem vessels because it might block they xylem.
To avoid introduction of air bubbles in the xylem.
For continuity of water uptake.
Availability of water
K.C.S.E Biology Q & A - MODEL 2004PP1QN10
How are the xylem vessels adapted for support?
K.C.S.E Biology Q & A - MODEL 2003PP1QN09
a) Material that strengthens xylem tissue.
b) Tissue that is removed when the bark of a dicotyledonous plant is ringed.
K.C.S.E Biology Q & A - MODEL 1996PP1QN 19
The diagram below represents then pathways of water from the soil into the plant.
(a) Name the structures labeled K and L.
(b) Explain how water from the soil reaches the structure labeled L.
(c) Name the process by which mineral salts enter into the plant
(a) K- Root hair
L- Xylem vessel
(b) Water moves from the soil into the root hair by osmosis; because concentration of cell sap is higher than water in the soil; the cell sap in the root hair is diluted, thus making it less concentrated than neighboring cell; therefore water moves into the neighboring cell; it is actively secreted into structure L.
(c) Active transport/ diffusion