skema pecutan.docx

4551/2 PEPERIKSAAN PERCUBAAN 2009 SULIT

F1 : Concentration of glucose / amino acid / urea / sodium ions in the blood plasma and glomerular filtrate are the same.

E1 : All glucose / amino acid / urea / sodium ionsenter the Bowman’s capsule / nephron / are in the glomerular filtrate

E2 : through ultrafiltration.

E3 : Able to pass through the wall of blood capillaries / Bowman’s capsule.

F2: No glucose / amino acid in the urine.

E4 : All glucose / and amino acid are reabsorbed from the proximal convoluted tubule / nephron

E5 : by facilitated diffusion / active transport into the(peritubular) capillaries // blood capillaries

F3 : Less sodium ions in the urine than in the blood plasma / glomerular filtrate.

E6 : Some sodium ion have been reabsorbed from theNephron (by active transport into the peritubular capillaries // blood capillaries)

F4 : No protein in the glomerular filtrate / urine.

E7 : They are large molecules.

E8 : Unable to pass through the wall of blood capillaries / Bowman’s capsule.

F5 : Very high content of urea in the urine.

E9 : Secretion of urea into the nephron at the distal convoluted tubules

Any ten points

1

1

1

1

1

1

1

1

1

1

1

1

1 Max

10

(b) (ii) Able to explain changes that might occur to the content of the adult’s urine.

Sample answer:

E1 : excess glucose is found in his urine 1

13


E2

E3

E4

Ablecontent

Sample

F1

P1

P2

P3

Biodiversity is important

for several reasons:

F- it provides humans with necessities of life 1P- is a resource for food /timber to build shelter / as a

fuel/fibers for clothing 1F- 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 1 populationP- Regulate climatic conditions, biogeochemical cycles, 1

prevent floodingF- Natural ecosystems and species in the wild are 1

beautifulP- 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 ofoxygen) 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


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 provide food for the zooplankton. When these organisms die and decompose, there is more organic matter in the pond. 1These organic matter provides nutrients for growth ofsubmerged plants.

Submerged plants such as Hydrilla and Elodea are now found in the pond. They can photosynthesise and spread 1rapidly by vegetative propagation.

When the submerged plants die, they sink to the bottom. They are decomposed and the humus layer becomes 1thicker. 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 as Lemna, Eichornia andNymphaea 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 1formed.

As the pond becomes more shallow and fertile, the floating plants are gradually replaced by emergent plants. Sedges, for example, Cyperus and Fimbristylis are found on the 1edge of the pond.

As more plants die and decompose, the pond becomes even more shallow. The floating plants die and sedges and other emergent plants spread from the edge to the middle of the 1pond.

Eventually the pond is filled with soil and becomes drier.


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

QUESTION 9


QUESTION 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 responseP-is slow in plants, is fast in humans

F-Duration of responseP-for plants response lasts longer if the stimulus stays

the same; it involve either a rapid response for humans.

F-Location of responseP-for plants, a response takes place at the region just

below the shoot tip or above the root tip; for humans response takes place in one or more specificeffectors in different parts of the body.

F-Nature of messageP- for plants it is chemical; for human it is both

chemical (hormone) and electrical

F-Type of responseP- for plants it is a growth movement caused by cell

division and cell elongation; for humans it involves muscular contraction or secretions from glands

Any 2Fs and 2Ps

1

1

2

11

1

1

1

1

1

1

1

1

8

10

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