QUESTION 5:
(a) (i) State three difference between the alimentary canals of earthworm and
cockroach. [3 marks]
(ii) State three similarities between the alimentary canals of earthworm and cockroach. [3 marks]
(b) The diagram below is an illustration of a biological cycle. Study it and answer questions 5(b)(i) to 5(b)(iii).
(i) Name the biological cycle. [1 mark]
(ii) Explain briefly three roles played by plants and animals in the cycle.
[3 marks]
(iii) Name the processes that occur in X,Y and Z. [3 marks]
(c) Complete the table below.
|
Organ associated with excretion in humans |
Three diseases each that affect the organ |
(i) |
|
|
(ii) |
|
|
[8 marks]
(d) (i) what is decay of organic matter? [2 marks]
(ii) Name two groups of organisms that cause decay of organic
matter. [2 marks]
(iii) State one other factor that causes decay. [1 mark]
(iv) Name the biological cycle that involves decay. [1 mark]
(e) Explain briefly the mode of nutrition in carnivorous plants. [3 marks]
This was a compulsory question and candidates performed relatively well in it.
Many candidates were able to state similarities between the alimentary canal of earthworm and cockroach.
Some of them were also able to name the processes in the diagram and state the roles played by plants and animals.
They could also complete the table on the organ associated with excretion and the corresponding diseases of the organs named.
Candidates were able to name groups of organisms that cause decay of organic matter.
However, many candidates showed weaknesses in explaining the mode if nutrition in carnivorous plants.
The expected answers are:
5. (a) (i) Differences between the alimentary canals of an earthworm and a cockroach
Earthworm |
Cockroach |
|
elaborate/biting/chewing mouthparts; |
simple |
alimentary canal divided into fore gut, |
|
presence of mesenteric caecum; |
|
malpighian tubules attached to canals. |
Note: points must correspond to score.
(ii) Similarities
Both have
- Mouth;
- Crop;
- Gizzard;
- (Small) intestines;
- Oesophagus;
- Anus.
Note: Spellings must be correct to score.
(b) (i) Name of biological cycle
Water
(ii) Roles of plants and animals in the cycle
- Plants and animals produce water as a by-product of respiration;
- plants give-off water through transpiration;
- animals give off water by perspiration/sweating/urinating/excretion;
- plants absorb water/animals drink water for body metabolism.
(iii) Processes that occur in X, Y and Z
X - Condensation
Y - Evaporation
Z - Evaporation
Note: Spellings must be correct to score.
(c) Table
Organ associated with excretion in humans |
Three diseases that affect the organ |
Kidneys |
Nephritis; kidney stones; diuresis; kidney |
Liver |
Cirrhosis; hepatitis; jaundice; dropsy; |
Skin |
Scabies; ringworm; acne; eczema; |
Lungs |
Bronchitis; cancer; asthma; tuberculosis; |
Note: (i) spelling of organs and diseases must be correct to score;
(ii) organ must be correct for the disease to score;
(iii) not more than three diseases should score for each of the two organs
(iv) the total mark is 8marks.
(d) (i) Decay
Is the breakdown of complex organic matter; into small/simple compounds; so that their nutrient can be absorbed.
(ii) Group of organisms that bring about decay
Saprophytes/fungi; bacteria; detritivores/decomposers.
(iii) Factor that brings about decay
- Temperature/Heat/warmth;
- Osmotic pressure;
- Amount of water;
- Amount of oxygen.
(iv) Biological cycle that involves decay
Carbon; Nitrogen
(e) Mode of nutrition in carnivorous plants
- They obtain nutrients from trapped insects and other small animals;
- The trapped insects are digested;
- And the amino acids are absorbed;
- Carnivorous plants grow on soils that are poor in nitrogen;
- Animal proteins supplement the nitrogenous compound