Question 1
A group of students set up an experiment to investigate a certain physiological process. The set up was as shown in the diagram below
- What physiological process was being investigated
-
i) State two major observations that made after some time.
ii) Account for the above observations in b(i) above - State the significance of the biological process involved in the experiment
Answer
- Osmosis
-
i) - Distilled in the Irish potato would reduce in level;
- Level of concentrated salt solution would increase in the Petri dish;
ii) Concentrated salt solution in the Petri – dish has higher osmotic pressure than the cells of the Irish potato; these cells lost water to the salt solution by osmosis; these cells because more concentrated and drew water from the neighboring cells; this process continued until the cells in contact with water in the potato drew it up -
- Absorption of water
- Opening and closing of stomata
Question 2.
A shoot of a seedling exposed to light on one side bends towards the source of light as it grows
- Name the response exhibited by the shoot of the seedling.
- Explain how the bending towards the sources of light occurs.
- Give three roles of tropism to plants
Answer
- Phototropism
- Auxins / IAA ; produced by the tip of the shoot ;diffuse / move to the dark side / away from the lit side / non illuminated side ; causing more cell / Division and ) elongation / growth on the dark side;
-
- Exposes leaves / shoot in position for aborption of more light;
- Enables roots of plants to seek / reach / search for water to facilitate fertilization;
- Enables herbicides plants to obtain mechanical support
Question 3
The equation bellows shows a chemical reaction that takes place in green plants under certain conditions
Carbon (IV) Oxide + Water → Glucose + X
- Name the
(i) Substance represent by X
(ii) Process represented by the equation - Other than the reactancts, state two conditions necessary for this reaction to occur
- Name three types of cells in which the process occurs
- Define a compensation point
Answer
- i) Oxygen
ii) Photosynthesis - - Presence of light ;
- Presence of chlorophyll; - - Palisable cells;
- Guard cells;
- Spongy mesophyl ;
- Palisade mesophyl; - Point when rate of oxygen production and carbon (IV) Oxide consumption are equal
Question 4
The diagram below represents a maize seedling
- Name the parts labelled P and Q
- State the function of the part labelled R
- Give three adaptations of the structure labelled S to its functions
- What is the role of air in germination of the above seedlings
Answer
-
P - Coleoptile / plumule sheath ;
Q - Root ; - R - Storage of food / Enzyme / to provide food to the seedlings;
-
- Elongated to increase surface area for absorption of water ;
- Has many mitochondria for active transport;
- Has thin wall / thin walled for paste absorption of water and mineral salts - Air contains oxygen for respiration / oxidation to produce energy
Question 5
A study was carried out to investigate the distribution of certain mammals in a game reserve with three different habitats. The results are shown in the table below.
From the above table suggest:
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i) a suitable method that could have been used to obtain the data from the three habitats
ii) Three reasons why all the mammalian species were found in the wounded grassland - From the data, deduce the feeding The vegetation in this game reserve was destroyed by fire. Two weeks after the onset of rains, most of the animals were found in the grassland. Explain
Answer
-
i) Belt transect / total count / physical count;
ii) - More food variety available ;
- Better comonflaged
- Presence of shelter / shade -
i) Grazer / feeds on grass ;
ii) Browser / feeds on twigs and leaves - Grass regenerates / grows / sprouts fasters then trees ; hence more forage was available in the grassland