BIOLOGY PRACTICAL QUESTIONS AND ANSWERS – UGENYA – UGUNJA DISTRICT

BIOLOGY PRACTICAL QUESTIONS – UGENYA – UGUNJA DISTRICT

Each student should be provided with the following:-

• Onion bulb
  
• Iodine solution (5ml)
  
• Cover slip (1pc)
  
• Microscope slide (1pc)
  
• Means of labeling
  
• Hydrogen peroxide – 5ml per student
  
• Test tube (4)
  
• Distilled water
  
• Saturated sodium Chloride solution – Liquid H – 5ml per student
  
• Blotting paper (1pc)
  
• Means of timing
  
• Pestle and Mortar
  
• Piece of liver
  
• Wooden splint
  
• Benedicts solution – 5ml
  
• Scalpel blade
  
• Means of heating
  
• Boiling tube (1)
  
• Glass rod
  
• A pair of forceps
  
• Microscope (one for a group of five)
  

N/B – Provide a medium power objective lens of x10 and eye piece lens of x10 or x15.

1.  You are provided with a portion of an onion bulb. Remove one fleshy leaf from the onion bulb, peel the epidermis from the inner surface of the leaf and place it on a drop of iodine solution on a glass slide. Place a cover slip on the epidermis. Drain the excess iodine solution by use of a piece of blotting paper from the edge of the cover slip then leave the set up for one minute.

Place a drop of liquid H at the edge of the cover slip. Leave the set up for 5 minutes then drain excess liquid from the opposite of the slip using a blotting paper. Observe under medium power of the light microscope provided.

(a) Draw and label two neghbouring cells  

(b) Account for the results in (a) above  

(c) Using a pestle and mortar, crush two fleshy leaves of the onion bulb, add 4mls of distilled

water and stir. Decant into a test tube and label the resultant filtrate as solution J₁ and retain

the residue.

Using the reagents provided, carry out food tests on solution J₁ and fill the table below:

(d) Label one test tube as J₂ and another as K . Add 2mls of Hydrogen peroxide to each of the

test tubes.

  (i) Into the test tube labelled J₂, place the entire residue obtained in (c) above and immediately

introduce a glowing splint. Record your observations in the table below. Into the test tube

labelled K, place the piece of liver provided then immediately introduce a glowing splint

into the mouth of test tube and record your observations in the table below.

(ii) Name the enzyme responsible for the reactions in the test tubes above

  (iii) Explain the significance of the difference in the observations in part (i) above  

2.  Use the diagram provided to answer questions that follow:

(a) Name the bones that articulate with the structure labelled P

(i) Dorsally  ………………………………………………….

(ii) Ventrally……………………………………………………………………….

(b) Give three adaptations of structure M to its functions

 (c) (i) Name the fluid found within the part labelled S

(ii) State the function of the fluid named in (c) (i) above

(d) Identify the parts labelled: Q & R  

(e) State two changes that take place in the organ labelled N when the structure Y contracts

 (f) How is large surface area achieved for efficient functioning of the organ labelled N?  

3.  A student collected a number of invertebrates whose photographs appear below. He constructed a Dichotomous key as shown below to enable him place each specimen into its taxonomic group

photographs

DICHOTOMUS KEY

 1. (a) Organisms with a flat body  Go to 9

  (b) Organisms without a flat body  Go to 2

 2. (a) Organisms having a body in a shell Mollusca

  (b) Organisms without a shell  Go to 3

 3. (a) Organisms having a segmented body Go to 4

  (b) Organisms with a body not segmented Nematoda

 4. (a) Organisms having jointed appendages Go to 6

  (b) Organisms without jointed appendages Go to 5

 5.(a) Organisms with a long cylindrical body Annelida

  (b) Organisms having a short stout body Trematoda

 6. (a) Organisms with antennae  Go to 7

  (b) Organisms lacking antennae  Go to 8

 7. (a) Organisms with a pair of antennae Insecta

  (b) Organisms with more than one pair of antennae  crustacea

 8. (a) Organisms with pincer-like mouth parts Arachnida

  (b) Organisms with sucking mouth parts Acarina

 9. (a) Organisms having a ribbon like body Cestoda

  (b) Organisms with circular body  Crinoidea

 (a) Using the dichotomous key, identify the taxonomic group of each of the five specimens

  shown in the photographs. In each case show in sequence, the steps in the key that you

have followed to arrive at the identity of each specimen  .  

 (b) Name a pathogen that attacks human beings and is associated with the organism labelled V

UGENYA- UGUNJA DISTRICT BIOLOGY PRACTICAL MARKING SCHEME (ANSWERS)

1. a)

D – 1 ½ P – 1

Mag: x100 or x150 L – ⁴/_{2 Cl – ½}

 Mag – ½

 b) Liquid H is hypertonic/ highly concentrated; to cause a high osmotic pressure; water  

molecules are drawn from the onion epidermal cells by osmosis; excess water loss results in

the plasma membrane detaching from the cell wall/ hence the cell is plasmolysed; (OWTTE)  

c)  

d)   i)

ii) Enzyme catalase;

iii) The liver has more catalase enzyme; since it undertakes the role of detoxification  

in mammals;  

3.  i)

 ii) Schistosoma sp / S. haematobium / S. japonicum

rej.  – when not underlined separately.

– Wrong spelling.

– Lower case “S” for 1^st letter.