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4551/2 PEPERIKSAAN PERCUBAAN 2009 SULIT

E2 : glucose cannot be converted into glycogen

E3 : Excess glucose will not be reabsorbed from the

nephron // proximal convoluted tubules

E4 : into ( peritubular) capillaries // blood capillaries

Any three points

Able to suggest a laboratory experiment to confirm thecontent of the urine

Sample answer:

F1 : (The laboratory experiment to be conducted) isthe Benedictstest.

P1 : (In a test tube) , add about 1 ml of urine samplewith 1 ml of Benedictssolution

P2 : The mixture is heated (in a water bath) for 5minutes

P3 : Observe the presence of brick red precipitate toconfirm the presence of glucose in the urine

Any three points

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Biodiversity is

important

for severalreasons:

F- itprovides humans with necessities of life 1

P- is a resource for food /timber to build shelter / as afuel/fibers for clothing 1

F- many plant species are original sources of

pharmaceutical drugs/medicines. 1P- New commodities, for example, new crop plants or

medicinal materials could be developed using the gene 1

pool from wild species in the forests.

F-Allow for biological control to maintain stable 1population

P- Regulate climatic conditions, biogeochemical cycles, 1

prevent flooding

F- Natural ecosystems and species in the wild are 1beautiful

P- there is much pleasure to be derived from unspoilt

natural environment. 1F- Ecotourism 1

P-could provide income for some countries 1Any 2F and 2P

4

Waste materials from households

- rich in organic matters,bacteria and microorganism 1

- (in oxidation pond) the sewage is decomposed by(millions0 of aerobic bacteria (in the presence of

oxygen) 1

- Decomposed sewage /sludge settled to the bottomof the pond 1

- Fermentation takes place at (sedimentation tanks) 1

- Using anaerobic bacteria 1- Produce methane/carbon dioxide/minerals 1

- Digested sludge used as fertilisers 1

Any 6 6


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8(b) The first coloniser are the plankton and algae. These

species are usually brought in by muddy feet of birds and

other animals that visit the pond. 1

The phytoplankton and algae photosynthesise and providefood for the zooplankton. When these organisms die and

decompose, there is more organic matter in the pond. 1

These organic matter provides nutrients for growth ofsubmerged plants.

Submerged plants such asHydrilla andElodea are now

found in the pond. They can photosynthesise and spread 1

rapidly by vegetative propagation.

When the submerged plants die, they sink to the bottom.

They are decomposed and the humus layer becomes 1

thicker. Soil is also eroded into the pond and the pondbecomes shallower.

The conditions become unsuitable for submerged plants

but more favourable for floating plants. The seeds are

usually brought in by birds and animals that use pond.

1

The floating plants such asLemna, Eichornia and

Nymphaea now grow in the pond.

1

The floating plants cover a large area of the surface water

and reduce the amount of sunlight to submerged plants.

The submerged plants die, decompose and more humus is 1

formed.

As the pond becomes more shallow and fertile, the floating

plants are gradually replaced by emergent plants. Sedges,

for example, Cyperus andFimbristylis are found on the 1

edge of the pond.

As more plants die and decompose, the pond becomes evenmore shallow. The floating plants die and sedges and other

emergent plants spread from the edge to the middle of the 1

pond.

Eventually the pond is filled with soil and becomes drier.


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Terrestrial herbaceous plant such as Euphorbia hirta, 1Ageratum conyziodes and other grasses grow in the area.

The land becomes drier and more fertile.

The herbaceous plants are gradually replaced by shrubs 1

and small trees.

Eventually a terrestrial forest is formed.

1

10

TOTAL 20


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QUESTION 9QUESTION 9

No Marking Criteria Marks

(a) Similarities

- plants and humans are exposed to stimuli from the

external environment, such as light, water,

chemical, etc.

- these external stimuli stimulates automatic or

involuntary responses in plant and reflex actions in

humans,

Differences

F-rate of response

P-is slow in plants, is fast in humans

F-Duration of response

P-for plants response lasts longer if the stimulus stays

the same; it involve either a rapid response for

humans.

F-Location of response

P-for plants, a response takes place at the region justbelow the shoot tip or above the root tip; for humans

response takes place in one or more specific

effectors in different parts of the body.

F-Nature of message

P- for plants it is chemical; for human it is both

chemical (hormone) and electrical

F-Type of response

P- for plants it is a growth movement caused by celldivision and cell elongation; for humans it involvesmuscular contraction or secretions from glands

Any 2Fs and 2Ps

1

1

2

1

1

1

1

1

1

1

1

1

1

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