QUESTIONS
- You are provided with solution W ,Solid Q, Iodine solution ,Benedict’s solution, Hydrochloric acid and Water bath.
- Using reagents provided carry out tests to determine the food substance present in solution W
Record the procedure ,observation and conclusion in the table below
Food test Procedure Observation Conclusion - Label three test tubes as A, B and C. Place 3ml of Solution W into each test tube. Divide solid Q into three equal portions.
To the test tube A add one portion of solid Q and shake thoroughly
To the test tube B add the second portion of Solid Q shake thoroughly and heat to boil.
To the test tube C add the third portion of solid Q, followed by 8 drops of 2M hydrochloric acid and shake to mix.
Place the three set ups into a water bath maintained at 37oc for 40 minutes.
Add equal amounts of Benedict’s solution to each of three test tubes and heat to boil. Record your observation.
Set up A ………………………………………………………………………1mk
B ………………………………………………………………………1mk
C ……………………………………………………………………...1mk
Account for your observations above (3mks) - Name any other factor that affects the reaction above. (1mk)
- Give a reason why temperature of the water bath was maintained at 37oc (1mk)
- Using reagents provided carry out tests to determine the food substance present in solution W
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- You are provided with Flower specimen K. Use it to answer the questions that follow
- Name the type of gynoecium in the flower.(1mk)
- With a reason state the agent of pollination.
Agent of pollination………………………………………………………….……………1mk
Reason ………………………………………………………………………………….. 1mk
- The photographs labelled Q, R,and S are sections of some plant parts.
- Name the type of placentation in the specimens shown in photographs Q, R and S .With
Reasons (6 marks)
Fruit Placentation Reason - Giving a reason in each case, name the mode of dispersal of the specimen in photograph Q and S (4marks)
Q
Mode………………………………………………
Reason……………………………………………
S
Mode………………………………..……………
Reason…………………………………………… - What type of fruit is R .Give a reason.(2mks)
- Name the type of placentation in the specimens shown in photographs Q, R and S .With
- You are provided with Flower specimen K. Use it to answer the questions that follow
- The diagram below represents a section of human skeleton and muscles.
-
- Name the parts labelled : W, S, R, Q 1mk
- What is the significance of part A (1mk)
- Describe the role of Q during inhalation. (2mks)
- Name the type of muscle on the diagram above.(1mk)
- What type of joint is at P (1mk)
- Name the bone that articulate with R at:
- Proximal end (1mk)
- Distal end (1mk)
-
CONFIDENTIAL
REQUIREMENTS
- Each candidate will require;
- 50ml of Solution W- Starch solution, prepared with warm water.
- Solid Q -5g of Diastase in a stoppered container
- 4 test tubes in a rack
- 4 Droppers
- 100ml plastic beaker
- 10ml measuring cylinder
- Test tube holder
- Spatula
- Three labels
- Means of timing(Wall clock/stop watch)
Access to
- Benedict’s solution placed in a test tube with a dropper
- 1M Hydrochloric acid with dropper.
- Iodine solution with a dropper
- Source of heat
- Hot water bath maintained at 37ºC
NB/Question 2 and 3 Photos should be coloured
MARKING SCHEME
-
Food test Procedure Observation Conclusion Reducing sugar(s);
Reject: Specific sugars e.g. Glucose/ Simple sugars/ Monosaccharide(s)To 1ml/ 2ml or drops of the solution W (in a test tube) add 1ml/ 2ml\drops of Benedict’s solution; [food substance and Benedict’s solution used must be the Equal proportion] Heat to boil/ Accept Place in a hot water bath
√Reject: Benedict ^/ benedict’s/ Benedict’s only
Note: √Procedure must be correct, all the way√ Quantities used- ratio of 1:1Blue colour persist Reducing sugars Absent
Starch To the( drops /2ml/1ml )of solution W in a testtube ,Add drops iodine solution
Reject ,iodine onlyBlue black colour
Reject any other colour,
Accept blackStarch present - Set up
A - Orange colour 1mk
B - Blue colour/ Green 1mk
C - Blue colour/ Green 1mk
Account for your observations above 3mks
Solid Q was an enzyme Hydrolysed/breakdown Starch into sugars/Glucose in A
In testtube B Boiling denatured the enzyme hence starch was not hydrolysed.
In testtube C Starch was not hydrolysed ,Acidic pH denatured the enzyme - Substrate concentration; Inhibition ; Coenzyme and co-Factor
- To provide Optimum/suitable temperature for enzyme reaction.
-
-
-
- Syncarpous
- Agent of pollination……Insect Accept correct example of an insect eg Bee1mk
Reason 1mk
Brightly coloured petals
-
- Q Marginal placentation - Placenta running longitudinally with seeds in a single line
R Axile/ central placentation –Placenta centrally placed/ presence of loculi/chambers
S Parietal placentation.-Ovary wall divided by placenta which is on ridges with many seeds attached - Q Mode Self - dispersal
Reason - The pods contains lines of weakness/sutures.
S Mode - Animal
Reason - Succulent /fleshy /brightly coloured. Any 1mk - Berry
Reason:- Has a centrally placed placenta
- Has many seeds
- Presence of loculi(with juicy sacs)
- Q Marginal placentation - Placenta running longitudinally with seeds in a single line
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-
-
- W - Ilium
S - Rib
R - Humerus
Q - External intercoastal muscles - Allow passage of nerves and blood vessels(1mk)
Make pelvic girdle less denser/lighter to reduce the weight load supported by hind limb - It Contract moving Ribcage upward and outward,This increase volume of thoracic cavity reducing pressure in the thoracic cavity.
- Skeletal Muscle;
- Ball and socket
- W - Ilium
-
- Scapula (1mk)
- Ulna (1mk)
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