Question 1
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(a) State two roles each of the following compounds in respiration:
(i) glucose;
(ii) oxygen. [4 marks]
(b) List two types of cellular respiration [2 marks]
(c) Name the structures of gaseous exchange in the following organisms:
[4 marks]
S/NoOrganism
Structure of gaseous exchange
(i)
(ii)
(iii)
(iv)
Amoeba
Tilapia
Adult toad
Grasshopper
(d) Make a diagram, 6 cm to 8 cm long of an open stoma in a leaf and label fully. [10 marks]
Observation
A few candidates could state the roles of glucose and oxygen in respiration, majority could list the types of cellular respiration.
A few candidates could name the structures of gaseous exchange in the listed organisms, although majority lost mark to poor spellings and interchange of answers.
Just a few of the candidates could make the drawing of stoma and label fully. Some actually drew a leaf instead of the stoma.
The expected answers are:
(a) Roles of the following compounds in respiration
(i) Glucose
Is broken down to give energy/ (ATP); carbon dioxide; and water is given off.
(ii) Oxygen
Oxidises/ breaks down/ burns; the glucose, releasing energy completely.
(b) Types of cellular respiration
Aerobic; Anaerobic
Note: spelling must be correct to score.
(c) Structures of gaseous exchange
S/No. |
Organism |
Structures of gaseous exchange |
i. |
Amoeba |
Cell membrane/ entire body surface |
ii. |
Tilapia |
Gills |
iii. |
Adult toad |
Lungs, skin, buccal cavity |
iv. |
Grasshopper |
Trachea/tracheole |
Note: spellings must be correct to score.
(d) Diagram of an open stoma in leaf
Title (TL) Open stoma in a leaf
Details (D)
Clarity of lines (CL)
Size (Sz) measure across the diagram or transversely
Neatness of labels (NL)
Quality (Q)
Bean shaped guard cells (BG)
Chloroplast shown on guard cells (CS)
Opening of stoma clearly shown (OS)
Labels (L)
Chloroplast; epidermal cells; stoma; nucleus; thin outer wall; thick inner wall; guard cells; sap vacuole