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a) The action of ptyalin stops at the stomach. Explain.
b) State a factor that denatures enzymes
c) Name the features that increase the surface area of small intestines
Date posted:
May 1, 2017
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The diagram below represents a section though a human tooth
a) i) Name the type of tooth shown.
ii) Give a reason for your answer in (a)(i) above.
b) State the functions of potassium ions in the human body.
Date posted:
May 1, 2017
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a) Distinguish between the terms homodont and heterodont
b) What is the function of carnassial teeth?
Date posted:
May 1, 2017
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What happens to excess fatty acids and glycerol in the body
Date posted:
May 1, 2017
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The set up below illustrates a procedure that was carried out in the laboratory with a leaf plucked from a green plant that had been growing in sunlight.
i) What was the purpose of the above procedure?
ii) Give reason for carrying out steps A, B and C in this procedure.
iii) Name the reagent that was used at the step labelled D.
iv) State the expected result on the leaf after adding the reagent named in (iii) above.
Date posted:
May 1, 2017
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A potted plant was kept in the dark for 48 hours. Two leaves X and Y were treated as shown in the diagram below.
The experimental set-up was kept in sun light for six hours after which a starch test was carried out on the two leaves
a) What were the results of the starch test on leaves X and Y?
b) Give reasons for your answers in (a) above
Date posted:
May 1, 2017
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The diagram below represents a set - up that was used to investigate certain process in a plant.
a) State the process that was being investigated
b) State a factor that would affect the process
Date posted:
May 1, 2017
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The diagram below represents a cell.
a) Name the parts labeled X and Y
b) Suggest why structures labelled X and would be more on one side than the other
Date posted:
May 1, 2017
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The graph below shows the effect of substrate concentration on the rate of enzyme reaction
a) i) Account for the shape of the graph between A and B.
ii) B and C
b) How can the rate of reaction be increased after point B?
c) State two other factors that affect the rate of enzyme reaction
Date posted:
May 1, 2017
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In an experiment to investigate a factor affecting photosynthesis, a leaf of a potted plant which had been kept in the dark overnight was covered with aluminum foil as shown in the diagram below.
The set up was kept in sunlight for three hours after which a food test was carried out on the leaf.
a) Which factor was being investigated in the experiment?
b) What food test was carried out?
c) Why was it necessary to keep the plant in darkness before the experiment?
Date posted:
May 1, 2017
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A freshly obtained dandelion stem measuring 5 cm long was split lengthwise to obtain two similar pieces. The pieces were placed in solutions of different concentrations in petri dishes (L1 and L2) for 20 minutes. The appearance after 20 minutes is as shown
State the significance of the biological process involved in the experiment
Date posted:
May 1, 2017
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The table below shows the concentration of sodium and iodine in sea water and cell sap of a plant
a) i) Name the process through which the plant cells take up sodium ions.
ii) Give a reason for your answer in (a) above
b) If the plant was sprayed with a chemical that inhibits respiration:
i) Which of the two ions uptake will be affected?
ii) Give a reason for your answer in (b) (i) above
Date posted:
May 1, 2017
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State two adaptations of chloroplast to its function
Date posted:
May 1, 2017
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Describe what happened during the light stage of photosynthesis
Date posted:
May 1, 2017
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What is the role of the vascular bundles in plant nutrition?
Date posted:
May 1, 2017
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Name two mineral elements that are necessary in the synthesis of chlorophyll
Date posted:
May 1, 2017
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Name the: a) Material that strengthens xylem tissue.
b) Tissue that is removed when the bark of a dicotyledonous plant is ringed.
Date posted:
May 1, 2017
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State the role of light in photosynthesis
Date posted:
May 1, 2017
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The diagram below shows a set-up for an experiment to demonstrate a certain physiology process.
a) What nature of solution is represented by 20% sugar solution?
b) Explain the observation made on the set-up after one hour.
Date posted:
April 29, 2017
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State three factors that affect the rate of diffusion
Date posted:
April 29, 2017
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In an investigation, a student extracted three pars of pawpaw cylinders using a cork borer. The cylinders were cut back to 50mm lenth and placed in a beaker containing a solution. The results after 40 minutes were as shown in the table below.
a) Account for the results in the table above
b) What would be suitable control set-up for the investigation?
Date posted:
April 29, 2017
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The diagram s below shows an experiment set-up to investigate a certain process in a plant tissue.
Explain the results obtained after 30 minutes
Date posted:
April 29, 2017
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Distinguish between haemolysis and plasmolysis.
Date posted:
April 29, 2017
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The diagram below show a red blood cell that was subjected to a certain treatment
Account for shape of the cell at the end of the experiment
Date posted:
April 28, 2017
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An experiment was set up as shown below
The set up was left for 30 minutes.
a) State the expected results.
b) Explain your answer in (a) above
Date posted:
April 28, 2017
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State the importance of osmosis in plant
Date posted:
April 28, 2017
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Why is oxygen important in the process of active transport in cells?
Date posted:
April 28, 2017
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A student drew a 6 cm long diagram of a plant flower. If the actual length of the flower was 12 cm, calculate the magnification of the drawing made by the student. Show your working
Date posted:
April 28, 2017
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The figure below is a fine structure of a generalized animal cell as seen under an electron microscope.
a) Name the parts labeled A and B.
b) How the is structure labeled B adapted to its function?
Date posted:
April 28, 2017
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Give reasons for carrying out the following procedures when preparing temporary wet mounts of plant tissues
a) Making thin plant sections.
b) Adding water on the plant section.
c) Placing a cover slip over the plant section.
Date posted:
April 28, 2017