Question 5
- Name four scientists that contributed to the development of the cell theory. [4 marks]
(b) In the table below, list three classes of plants based on their life cycles and name two examples each of the classes listed.
|
Classes of plants based on life cycles |
Two examples |
(i) |
|
|
(ii) |
|
|
(iii) |
|
|
[9 marks]
(c) State three adaptive features of the amnion in a developing foetus of a mammal. [6 marks]
(d) State one role each of the following organisms in the nitrogen cycle:
(i) Rhizobium;
(ii) Azotobacter;
(iii) Blue-green algae. [3 marks]
(e) Make a diagram, 6 cm – 8 cm long of the mouthpart of a butterfly and label fully. [8 marks]
Observation
This question was compulsory.
Question 6(a), Just a few candidates could attempt this question, some of them lost marks to the spelling mistakes of the names.
In 6(b), the marks lost were due to spelling mistakes e.g. anual, beinnial, per-annual e.t.c.
In 6(c), some candidates could not relate structure to function
In 6(d), most candidates mixed up the roles of each organism in the nitrogen cycle.
In 6(e), candidates made very poor or wrong drawing. Most of the drawings did not show the proboscis is coiled, wrong spelling mistakes in labels were also observed to have cause loss of marks.
The expected answers are:
(a) Scientists that contributed to the development of the cell theory
- Robert Hooke - Baptist Lamarck
- Theodor Schwann - Antonio van Leeuwenhoek
- Matthias Jakob Schleiden - Marcello Malpighi
- Rodolf/Rudolf Virchow - Jansen
- Felix Dujardin - Nehemiah Grew
Note: Spelling must be correct to score.
Any 4 x 1 [4 marks]
(b) Classification of plants and examples
S/No. |
Classes of plants based |
Two examples |
(i) |
Annual |
Maize, rice, cowpea/beans; millet; yam; cocoyam; |
(ii) |
Biennial |
Pepper; carrot; onion; pineapple; cassava; |
(iii) |
Perennial |
Mango; cocoa; orange; oil palm; avocado; |
Note: Spelling must be correct to score.
(c) Adaptive features of the amnion
- Amnion is thin; and covers the embryo;
- Contains amniotic cavity; filled with fluid; that protects the embryo from shock/mechanical injury/serves as shock absorber;
- Amniotic fluid; provides suitable temperature/moisture for the foetus;
- Contains slippery amniotic fluid; for easy passage/lubrication of foetus;
- Amniotic fluid; provides sterile/disease free environment; for foetal development.
Note:
Structure must correspond with function to score.
Structure x 1 mark; function x 1 mark.
Function alone does not score; Structure alone scores.
(d) Roles of the following organisms in a Nitrogen Cycle
(i) Rhizobium
Absorbs atmospheric nitrogen in the soil; to build up nitrates; which the plants use to form proteins.
(ii) Azotobacter
Produce nitrates from free nitrogen in soil; converts nitrite to nitrate.
(iii) Blue-green algae
Fix atmospheric nitrogen into nitrate.
(e) Diagram of the mouthpart of a butterfly
Title (TL)
Quality (Q)
Clarity of lines (CL)
Size (SZ) (6 cm to 8 cm)
Neatness of labels (NL)
Details (D)
Long coiled Proboscis (CP)
Labial palp shown (LP)
Labels (L)
- Proboscis; maxillary palp; labial palp; labrum; mandible