BIOLOGY PRACTICAL QUESTIONS AND ANSWERS – BUTERE EAST DISTRICT

 BIOLOGY PRACTICAL QUESTIONS – BUTERE EAST DISTRICT

 Each candidate should be provided with the following material/apparatus for the practical:-

• Medium sized Irish potato (1 piece each) labeled Q.
  
• Mortar and pestle.
  
• Scalpel
  
• Distilled water
  
• Cotton thread (20 cm long).
  
• Visking tube 15 cm long.
  
• 100 ml beaker.
  
• Stirring rod.
  
• Iodine solution.
  
• Means of timing.
  
• Photomicrographs labeled M and N.
  
• Transparent ruler graduated in mm
  
• Specimen K – Medium sized orange (should be moderately ripe and juicy)
  
• Test tubes (3 per candidate) in a test tube rack.
  
• DCPIP solution.
  
• Iodine solution.
  
• Benedicts solution.
  
• Means of heating water bath.
  
• Test tube holder.
  
• 3 droppers.
  
• 10 ml measuring cylinder.
  

1.  You are provided with a specimen labeled Q. Slice off about 2 cm thick disc from the

specimen. Peel it. Place the piece into a beaker and mash it into a paste using pestle and mortar.

Add 20 ml of distilled water and stir. Tie one end of the transparent visking tubing provided.

Decant the extract into the tubing and tie the other end tightly.

Ensure there is no leakage at both ends of tubing. Rinse the outside of tubing with water.

Immerse the tubing with its contents in a 100 ml beaker containing iodine solution. Allow to

stand for 20 minutes..  

a) Record your observations in the table below.

 (b) Account for the results obtained from (a) above.

 (c) What is the significance of the process being investigated to plants?

2.  Study the micrographs M and N show forms of a sexual reproduction in a certain group of

organisms. Study them and answer questions that follow.  

(a) (i) State the kingdom to which the two specimens belong.  

(ii) Give reason for your answer.

 (b) (i) What types of asexual reproduction are represented by the two specimens?

  (ii) State an example in each case of an organism that uses the type of reproduction named

above.

 (c) Consider the point marked X and Y. Measure the distances between the two in cm.

  (i) Distance ___________________________________ cm

  (ii) If the magnification of N is x60 of the actual specimen. What is the size of the actual

specimen in micrometers?  (Show your working)

What is the economic importance of the activities of M and N?  

3.  You are provided with the specimen labeled K. Make a transverse section of the

specimen  

(a) Draw and label the transverse section of the specimen.

(b) Which type of fruit is specimen K?  

(ii) How is the specimen adapted for dispersal by the agent named in c (i) above?  

(d) Squeeze the juice from the specimen K into a small beaker. Using the reagent provided to

test for the food substances in the juice. Record the substances, procedures, observations and

conclusions in the table below.

BUTERE EAST DISTRICT BIOLOGY PRACTICAL MARKING SCHEME (ANSWERS)

1.  a)

 b) – The extract inside the tubing contains starch, A blue – black was observed due to

diffusion of iodine from the beaker across the Viking tubing membrane; since iodine

has a low molecular size; –

Iodine solution retained the brown colour because starch molecules in the extract are

large; in size and could not pass through the pores of the viking tubing membrane;

into the beaker.

c) i) Gaseous exchange;

ii) Transpiration;  

iii) Translocation of sugars;  

2.  a) i. Fungi

  ii. Reproduce asexually by budding or sporulation.

 b) i) M – Budding

  N – Sporulation

  ii) M – Yeast  

  N – Rhizopus / Bread mould/mucor.,  

 c) i) 8.7 cm

  ii) Linear Magnification = Linear dimension of the Image

  Linear dimension of actual object  

  Linear dimension of Image = 8.7 cm x 10000 μm = 8700 μm

X60 = 8700 μm

  x

x = 8700 μm

60

X = 1450 μm

 d) M – Used in baking Industry and brewing Industry.

  N – Causes decay of dead organisms releasing nutrients. –

Causes food decay.

3.  a)

b) A berry/ hesperidium.

 c) i) Animal dispersal.

  ii) – Succulent endocarp/Juicy endocarp.

  – Scented

  – Bright colour exocarp.

  – Seeds resistant to digestion.  

 d)