BIOLOGY PAPER 3 - 2019 MOKASA II MOCKS EXAMINATION

PAPER 3

PRACTICAL

MOKASA II JOINT EVALUATION EXAMINATION

Kenya Certificate of Secondary Education

231/3

BIOLOGY

INSTRUCTIONS TO CANDIDATES

• Write your Name and Index No. in the spaces provided above
• Answer ALL the questions in the spaces provided

1. You are provided with the following: pieces of thread, two pieces of visking tubing 6cm, Distilled water in a beaker, iodine solution in a beaker, Solution Y and Solution X. Open the two viskingtubings and tie one end tightly. Using a dropper put 4 cm3 of Solution Y and 4 cm3 of solution X into each visking tubing, respectively. Ensure that the visking tubing containing solution X is immersed in the beaker containing iodine solution(set up B) and the visking tubing containing solution Y is immersed in beaker containing Distilled water (set up A) . Leave the set up for 30 minutes. Remove the Visking tubing and make observation
   1. State the observations    2 Marks
      A……………………………………
      B………………………………………
   2. State the physiological process in  (2Marks)
      A……………………………………
      B……………………………………
   3. Account for the observation made in
      A…………………………………… 2(marks)
      B……………………………………… 3(marks)
   4. State the importance of physiological process A in plants                                2 Marks
   5. How can you speed the process in B?                                                  1 Mark

2. Below are photographs of invertebrates which belong to the same class. Examine them
   1. To which class do the above invertebrates belong?                               1Mark
   2. State two characteristics of the class named in (a) above                       2 Marks
   3. Complete the dichotomous key below to identify the invertebrates to their orders 3marks
      1.  
         1. Animal with wings       ……………………………………………………go to 3
         2. Animal without wings …………………………………………………….go to 2
      2.  
         1. Animal with hairy body ……………………………………………………Siphonoptera
         2. Animal with smooth body……………………………………………………Isoptera
      3.  
         1. Animal with one pair of wings………………………………………………...Diptera
         2. Animal with two pairs of wings………………………………………….........go to 4
      4.  
         1. Fore wings hard/elytra…………………………………………………………Coleoptera
         2. …………………………………………………. ....Go to 5
      5.  
         1. Long slender abdomen…………………………………………………………Odonata
         2. Short broad abdomen…………………………………………………………..Hymenoptera
   4. Using the dichotomous key above, identify to which orders the various organisms belong. In each case write down the steps that you followed to arrive at your answer.       (6mks)
      

      Specimen	Steps	Identity
      R1
      R2
      R3
      R4
      R5
      R6

3. You are provided with specimen K. Use it to answer the questions that follow
   1. Describe the floral parts                                                                                      3 Marks
   2. Cut the specimen KDraw one of the sections   4 marks
   3. With a reason state the agent of pollination                                                       2 Marks
   4. The photographs labelled Q,R,andS are sections of some plant parts.
      1. Name the type of placentation in the specimens shown in photographs Q, R and S(3 marks)
      2. Giving a reason in each case, name the mode of dispersal of the specimen in photograph Qand S                                                                (4mark)
         

BIOLOGY

PAPER 3

PRACTICAL 

MOKASA II JOINT EVALUATION EXAMINATION MARKING SCHEME

1. State the observation     4 Marks
   A
   Shrinking of the visking tube
   Level of brine in the beaker increases
   B
   The starch in the visking tube turn blue black
   The iodine reduces
2. State the physiological process in             2Marks
   A Osmosis
   B Diffusion
   1. Account for the observation made in
      A – Distilled water is hypotonic to that in the brine in the beaker; hence water molecules move into the beaker by osmosis leading to shrinking of the visking tube 3Marks
      B – Iodine molecules are small in size hence able to pass through the small pores of the visking tubing from region of high concentration to regions of low concentration by diffusion ; leading to the blue back color             3Marks
   2. State the importance of physiological A in plants                                  2 Marks
      • Support in seedlings, leaves and herbaceous plants
      • Feeding in insectivorous plants
      • Opening and closing of the stomata
   3. How can you speed the process in B                                                   1Mark
      • Increasing the concentration of iodine
      • Introducing heat
3. To which class do the above invertebrates belong                               1Mark
   Insect
4. State two characteristics of the class named in (a) above                       2 Marks
   Have three body parts
   Have three pairs of walking legs
   Have a pair of antennae
   Have a pair of compound eyes
5. Complete the dichotomous key below to identify the invertebrates above to their orders 3marks

1a.Animal with wings       …………………………………………………… go to 3

b.Animal without wings   ………… ………………………………………….go to 2

2a. Animal with hairy body ……………………………………………………Siphonoptera

b. Animal with smooth body……………………………………………………Isoptera

3a. Animal with one pair of wings………………………………………………...Diptera

b. Animal with two pairs of wings …………………………………………..   go to 4

4a. Fore wings hard/elytra…………………………………………………………Coleoptera

b. Fore wings membranous……………………………………………………...Go to 5

5a. Long slender abdomen…………………………………………………………Odonata

b. Short broad abdomen…………………………………………………………..Hymenoptera

1. Using the dichotomous key above, identify to which orders the various organisms belong. In each case write down the steps that you followed to arrive at your answer.(6marks)

3. You are provided with specimen K. Use it to answer the questions that follow
   1. Describe the floral parts                                                                                      3 Marks
   2. Cut the specimen K Draw one of the sections                             4 marks
   3. With a reason state the agent of pollination                                                       2 Marks
      Insect
      Bright coloured petals to attract insects
      Scented and produce nectar that attract insects that feed on nectar
      Pollen grains are relatively large, heavy and rough so as to stick onto the body of the insect
   4. The photographs labelled Q,Rand S are sections of some plant parts.

(i)Name the type of placentation in the specimens shown in photographs Q, R and S(3 marks)

Q Marginalplacentation

RAxile/ central placentation

SParietal placentation

(ii)Giving a reason in each case, name the mode of dispersal of the specimen in photograph Q and S                             (4mark)

QMode

Self-dispersal

Reason

Fruits are found inside a pod. The pods contains lines of weakness

S

Mode

Animal

Reason

Succulent and brightly coloured.