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BIOLOGY PRACTICAL QUESTIONS – MIGORI DISTRICT
Each candidate should be provided with the following:
- Irish potato (one large one each – N)
- 75 ml of conc. brine labelled L1.
- 75 ml of distilled water labelled L2.
- Potato borers.
- Six test tubes.
- Iodine.
- Benedict’s solution.
- Sodium hydroxide.
- 10% copper II sulphate.
- Means of heating.
- Means of timing.
- A ruler.
Q.1 Below are two sets of photomicrographs A and B showing various processes of cell divisions.
Examine them.
Q. (a) Using observable features only, identify the type of cell division represented by the
photomicrographs in set A and set B. Give a reason in each case.
Cell division in set A
Reason:
Cell division in set B.
Reason:
(b) Name the division process represented by number 3 and 4 in photomicrographs of set A and
number 1 and 3 in photomicrographs in set B. Complete the table below.
(c) Name one region in higher pants where the cell division represented by photomicrographs
set A and B occurs.
(d) Describe the process that is taking place at photomicrographs set A number 3 and
photomicrograph set B number 2.
(e) State the importance of each of the cell division in
A and B in the bodies of living
organisms.
2. You are provided with specimen N. You have also been provided with a cork borer bore out
three (3) pieces each measuring 5 cm. Take each piece and place into the test tubes labelled
A, B and C separately.
Fill test tube A with solution labelled L1.
Fill test tube B with solution labelled L2.
Leave test tube labelled C empty (Do not pour anything into it.)
(a) (i) Remove the pieces and dry each using blotting paper and measure its length. Record in the
table below.
(ii) Account for the observation made in the measurements of each piece after 30 minutes
above.
(b) (i) Crush the remaining tissue into a paste and carry out food tests on it using the reagents
provided.:
(ii) What would imbalances of such food substances cause in the diet?
Excess of the foods.
Deficiency of the foods.
3. Study the photographs provided above and answer the questions below.
(a) Give the identity of T1 and T2.
(b) How is each specimen adapted to its function?
(c) Label the parts of T2 marked A to F
(d) State the effect of too much sugar in the diet on specimen T1 and T2
in humans.
(e) (i) What is the name of the gap found between T1
and T2
in herbivores.
(ii) State the function of the gap named in e(i) above.
MIGORI / NYATIKE DISTRICT BIOLOGY PRACTICAL MARKING SCHEME (ANSWERS)
1. (a) Set A Mitosis;
Reason:- Two (daughter) cells formed;
Set B Meiosis
Reason-Four (daughter) cells formed;
(b) A 3 Metaphase;
4 Anaphase;
B 1 Metaphase 1;
3 Telophase1;
(c) Set A – shoot tip/root tip/cambium /flower buds/apical meristems/cambium meristems;
Set B – Anther /ovary;
(d) Set A; number 4- Chromosome align at the equator
Set B: – number 2: Homologous chromosomes separate and move (migrate towards the
opposite poles;
(e) Set A- Results in growth;
Set B- Gamete formation/gamete variation
2. (i) A = 3mm;
B = 7mm
C = 5mm;
(ii) A- The solution (L1) is hypertonic to the cell sap of the potato tissue; water is drawn
out of them by osmosis; the cells become plasmolysed and flaccid and they shrink
/decreases in length;
B- The solution L2 is hypotonic to the cell sap of the potato tissue; they gain water by
osmosis; and become turgid. They cause the tissue to increase in length; C – No change; control experiment
(b)
FOOD SUBSTANCE | PROCEDURE | OBSERVATION | CONCLUSION |
STARCH | Add 3 drops iodine. Solution to food substance to be tested | Colour changes to blue-black (black) | Starch present |
REDUCING SUGAR | Add on equal amount of Benedict’s solution to the food substance and heat to boil | The colour changes from blue to green to yellow to orange and brown precipitate formed | Reducing sugar present |
PROTEIN | To about 2cm3 of food substance add 1cm3 of NaOH solution . Add 1-2 drops of copper sulphate | Purple or violet colour formed | Proteins present |
(b) Obesity;
Marasmus in children and muscle wasting in adults
3. (a) T1 – incisor; (tooth)
T2 – Molar; (tooth)
(b) Incisor (T1) – sharp /wedge-shaped; for cutting;
Molar (T2) – broad surface with cusps; for grinding
(c) A – Nerve
B- Pulp cavity
C – Enamel
D – Dentine
E – Blood vessel
F – Periodontal membranes
(d) Cause bacteria to grow and produce acids which cause tooth decay;
(e) (i) Diastema;
(ii) Allows movement of tongue when cutting grass and turning food in the mouth
