QUESTIONS
- You are provided with
- Liquid cooking oil
- B1
- B2
- Irish potato
Label two test tubes X and Y. Into each test tube, put 2cm3 of water and 8 drops of liquid cooking oil. To the test tube labeled X add 8 drops of liquid B1, shake both test tubes and allow the content to stand for 2 minutes-
- Record your observations in (2mks)
- Name the process that has taken place in test-tube X (1mk)
- State the significance of the process named in a (ii) above in digestion (1mk)
- Name the digestive juice in humans that has the same effect on oil as liquid B1 (1mk)
- Name the region in the digestive system into which the juice is secreted (1mk)
- Label two test tubes E and F. Place 2cm3 of liquid B2 into each. Add a drop of iodine solution into each test tube.
- Record your observation (1mk)
- Suggest the identity of liquid B2 (1mk)
- Cut out a cube whose sides are 1cm from the irish potato provided. Crush the cube to obtain a paste and place the paste in the test tube labeled E. Leave the set up for at least 30minutes.
Record your observation (2mks)
Contents of test tubes F after 30 min
Contents of test tube E after 30 min - Account for the results in b (iii) above. (1mks)
-
- Cut out another cube whose sides are 1cm from the Irish potato and crush it. Place the crushed paste into a test tube. Carry out food test with the reagent provided. Record the procedure and results. (2mks)
Food being tested Procedure Observation Conclusion - Account for the results in (c) (i) above. (3mks)
- Cut out another cube whose sides are 1cm from the Irish potato and crush it. Place the crushed paste into a test tube. Carry out food test with the reagent provided. Record the procedure and results. (2mks)
-
- The photographs labelled J, K and L are all related to mammalian kidney.
- Name the hormone produced by the structure labelled P. (1 mk)
- Name the parts labelled Q, R and T. (3 mks)
- State the process by which wastes are filtered from blood in the structure labelled S. (1 mks)
-
- Give two components of blood that that are not filtered at structure S.(2 mks)
- Give reason why the components you have named in d (i) above are not filtered. (2mks)
- Give two nutrients reabsorbed at the part labelled S. (2 mks)
- What two adaptations would be expected in the structure L in a desert animal like a camel. (2 mks)
- Below are drawings of specimens from plants. Study them and answer the questions that follow
- What is the role of the specimens to the plants. (1mk)
- Differentiate the specimen Q from specimen R. ( 2mks)
- Label the parts labelled C and D
- Explain what happens to the floral structures after fertilization. (4mks)
- With a reason state the class of plants from which the specimens were obtained. (2mks)
MARKING SCHEME
-
-
- Test tube X
Liquid becomes cloudy/turbid suspension formed/oil broken up into small droplets which are dispersed throughout the liquid. (The oil becomes emulsified)
Test tube Y
Oil floats on the water/two separate/immiscible layers are formed - Emulsification
- Increased surface area for action of enzyme lipase(answer tied to a (ii))
- Bile
- Duodenum (tied to (a) (ii) and (iv) )
- Test tube X
-
- Blue black
- Starch
- Contents of F remain unchanged. Blue black colour in E disappears/fades/changes to pale/light yellow/light brown/orange. (Answer tied to b (ii) )
- Enzyme/Amylase in potato breaks down starch/converts/hydrolyses/changes/digests starch into maltose/reducing sugars/simple sugars that do not give a blue black colour with iodine.(1mk)
Procedure
-
- Add equal amount of Benedict’s solution to paste and boil in a hot water bath
Food being tested Procedure Observation Conclusion Reducing sugar To the food substance add equal amounts of Benedict’s solution and heat/boil (in a hot water bath) Colour changes from blue to green to yellow to orange and finally brown or colour changes to brown Reducing sugars present
- Starch in potato is converted to maltose/glucose/reducing sugar by enzyme amylase/maltose/diastase. Rej ptylin
- Add equal amount of Benedict’s solution to paste and boil in a hot water bath
-
- The photographs labelled J, K and L are all related to mammalian kidney.
- Name the hormone produced by the structure labelled P.:
Adrenaline ;aldosterone (1 mk) - Name the parts labelled
Q - Cortex
R –pelvis
T- Collecting tubule (3mks) - State the process by which wastes are filtered from blood in the structure labelled S.
Ultrafiltration (1 mks) -
- Give two components of blood that that are not filtered at structure S.
Blood cells / Plasma protein (2 mks) - Give reason why the components you have named in d (i) above are not filtered. (2mks)
They have very large molecules; structures that can filter through the pores in the glomerulus.
- Give two components of blood that that are not filtered at structure S.
- Give two nutrients reabsorbed at the part labelled S
Glucose / Amino acids (2 mks) - What three adaptations would be expected in the structure L in a desert animal like a camel. (3 mks)
- Small glomerulus to reduce filtration of water.
- Long loop of Henle to maximize reabsorption of minerals (sodium salt)
- Very long distal convoluted lobule to increase surface area for water reabsorption.
- Highly coiled distal convoluted lobule to allow more time for water re-absorption.
- Name the hormone produced by the structure labelled P.:
-
- Reproduction ;
R Q Superior / hypogynous
Ovary ;Inferior / Ovary;Epigynous ovary Monocarpous Polycarpous / apocarpous / free capels - C – Anther ;
D- Sepal / Calyx ; - The petals degenerate / weather and are shed ;
The ovary develop into a fruit ;
The ovules develop into seeds
The ovary wall develop into a pericarp; - Class – dicotyledonae ;
Reason – The floral structure (anthers ) are in five in Q and 12 ( multiple of 4) in R ;
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