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BIOLOGY PRACTICAL QUESTIONS – KISUMU WEST DISTRICT

 

 Each candidate should have:-

  • Starch suspension labelled Liquid X
  • Iodine solution
  • Benedict’s solution
  • 2M hydrochloric acid (1ml)
  • 2 Droppers
  • Measuring cylinder (10ml size)
  • Means of heating/Bunsen burner
  • 5 test-tubes
  • Water in a small beaker
  • Thermometer
  • Test-tube holder
  • 3 boiling tubes
  • Tripod stand and gauze
  • 3 labels
  • White tile
  • Water bath
  • Diastase/ amylase enzyme (0.5g per student)

     

 N/B: –Liquid X is prepared by dissolving 5g of soluble starch in 50ml of distilled water.

  Thorough stirring is required whenever it is being used.

 

1.  You are provided with liquid X and substance Q

 (a) Place three drops of liquid X onto a white tile. Add four drops of iodine solution and record

  your observation.  

 (b) Pour 2ml of liquid X into a test-tube. Add equal amounts of Benedict’s solution and

  boil the mixture. Record your observation

(c) Label three boiling tubes as set-ups A, B, and C. Place 3ml of liquid X into each of the set-ups.

 Divide substance Q into three equal portions.  

 To set-up A, add one portion of substance Q and shake.

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  • Place the second portion of substance Q into a test tube. Add 1ml of water to it and boil for four minutes. Add it to set-up B and shake.
  • To set –up C, add the third portion of substance Q. Add 8 drops of 2M hydrochloric acid and shake.

 Place the three set-ups in a warm water bath maintained at 37oC for 40minutes.

 Cool the set-ups by dipping the boiling tubes in cold water

 Place 2ml of the contents of each set-up into three separate test tubes. Add equal amount of  Benedict’s solution to each of the three test-tubes and boil.

  Record your observations :-

 (d) Account for your observations in the set-ups:-

 (e) Give the most likely identity of substance Q  

 (f) Why was the water bath maintained at 37oC

2.  During a visit to a museum, students were shown some animals on display. Six of the animals

 are shown in the photographs below;

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 (a) Using observable features only, classify the animals, A, B and E into their respective classes.

  Give a reason for your answer in each case  

(b) State one morphological difference between C and E

(c) The dichotomous key constructed below can be used to identify some of the animals viewed in the museum:-

1. (a) Has jointed legs …………………………………………go to 2

(b) Lacks jointed legs ……………………………………..go to 3

2. (a) Has five or less pairs of legs ………………………. go to 4

(b) Has more than five pairs of legs …………………. go t o 5

3. (a) Has bilateral symmetry……………………………………………….EUNICE

(b) Has radial symmetry…………………………………………………..LUDIA
4. (a) Has five pairs of legs ……………………………………….CANCER

(b) Has four pairs of legs …………………………………….LACTRODECTUS

5. (a) Has I pair of legs per body segment …………………SCOLOPENDRA

(b) Has 2 pairs of legs per body segment ……………….SIGMORIA

 

 Use the dichotomous key above to identify animals labelled C, D and E. In each case show in

 sequence the steps followed (e.g. 1b, 2b, 3a e.t.c.) to arrive at the identity of each animal  

 

3.  Below are photographs I and II of young plants.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PHOTOGRAPH I PHOTOGRAPH II

 (a) With a reason in each case, name the class to which the plants belong:

(i) Plant in photograph I   ……………………………………………………………………………………..  

Reason………………………………………………………………………………………………………….  

(ii) Plant in photograph II  ………………………………………………………………………….  

Reason………………………………………………………………………………………………………….  

 (b) Identify the parts labelled G, J and M  

 (c) State two functions of the part labelled H  

 (d) (i) Name the swellings that would be developed in the roots of the plant in photograph I


later in its life  

  (ii) Which organism would be found in the swellings in (d)(i) above?

 (e) (i) State the type of germination exhibited by the plant in photograph II

(ii) Give a reason for your answer in (e) (i) above

 

 

 

KISUMU WEST DISTRICT BIOLOGY PRACTICAL MARKING SCHEME (ANSWERS)

1. (a) Blue black/black dark blue colour is formed

(b) No colour change/colour of Benedict’s solution remains;

Rej: No change /no reaction/ no observation /nothing happens

(c) Set-up A- colour changes from blue to green to yellow to orange/brown;

Set-up B: No colour change/ colour of Benedicts’ solution remains;

Rj- No change/no reaction/no observation/nothing happens

Set-up C- No colour change/colour of Bendict’s solution remains;

Rj- No change /no reaction/ no observation/ nothing happens

(d) Set-up A – Enzyme amylase/diastase/invertase (in Q); digests /hydrolisis/breaks down/

converts starch (in liquid X); to reducing sugar/maltose;

Set-up B: boiling denatures/destroys enzymes amylase/diastase/invertase; henc starch is

not converted to reducing sugar/maltose;

Set up C:- Hydrochloric acid provides unfavourable PH for enzyme amulase

diastase/invertase; hence starch is not converted to reducing sugar/maltose;

(e) Enzyme amylase/diastase/invertase;

(f) To provide optimum temperature for reaction of enzyme amylase/diastase;  

 

 

2. (a) (i) Chilopoda; Rj wrong spellings of classes but award marks for reasons

Reason – One pair of legs per body segment;

-Dorsoventrally flattened body; (consider first one only)

(ii) Insecta;

Reason- Body is divided into three parts/regions;

– Three pairs of legs;

– presence of wings;

(iii) Arachnida;

Reason:- Four pairs of limbs/legs;

C  E

  • 5pairs of legs 4Pairs of legs
  • Has antennae Lacks antennae
  • Lacks chelicerae /pedipalps  Has chelicerae/pedipalps
  • Has carapace Lacks carapace

(c)

ANIMAL

STEPS FOLLOWED

IDENTITY

C

1a, 2a, 4a;

CANCER;

D

1, 2b, 5b;

SIGMORIA;

E

1a, 2a, 4b;

LACTRODECTUS;

 

 

3.  (a) (i)Dicotyledonae;  Rej; wrong spellings of classes

  Reason: – Net-veined leaves

– Tap root system; Rj: tap roots (Mark first one  

(ii) Monocotyledonae;

 Reason :- Parallel –veined leaves;

  -Fibrous root system; Rj – Fibrous roots (mark first one)

(b)  G – Epicotyl; Rj wrong spellings  

  J- Hypocotyl;

   M – Prop roots;

(c) Stores food during germination

– turns green and carries out photosynthesis;

(d) (i) root nodules;  

 (ii) Rhizobium bacteria

(e) (i) Hypogeal germination;  

(ii) Cotyledon remains in the soil;

 


 




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