Answers to Hands on Pg 36 -42

 (a)

(i) Pancreas secretes insulin

(ii) Glucose converted to glycogen in liver cells

 (iii) Some glucose converted to fat

 (iv) Rate of cellular respiration increases

(b) (i) Pancreas secretes glucagon

 (ii) Liver cells breaks down glycogen to glucose

 (iii) Some fats converted to glucose

 (iv) Rate of cellular respiration decreases

 (c) (i) Erector muscles relax to lower body hair

 (ii) Vasodilation

(iii) Sweat glands secrete sweat

 (iv) Decrease in metabolic rate

 (d) (i) Erector muscles contract to raise body hair to trap air

 (ii) Vasoconstriction

(iii) Skeletal muscles stimulated to cause shivering

 (iv) Increase in metabolic rate

Objective Pg 38-40

1. A 2. B 3. B 4. A  5. A 6. C 7. C 8. C 9. D 10. D   11. D 12. D  13. C  14. A 15. D

16. D 17. B

Subjective Questions Pg 41-42

1. (a) (i) X : Afferent neurone

Y : Efferent neurone

(ii) X : Transmits impulses from receptors to the central nervous system

Y : Transmits impulses from the central nervous system to effectors

C (ii) When an impulse reaches the synaptic knob, it causes the vesicle containing neurotransmitters to move to the membrane and release the neurotransmitters. These neurotransmitters diffuse across and attach to the membrane of the dendrite of the next neurone which then stimulate the transmission of impulse.

2. (a) (i) Auxin

(ii) To stimulate the growth of coleoptile and to enable the coleoptile to respond to a stimulus

 (b) In Experiment 1, the presence of auxin in the tip of the shoot stimulates the growth of the coleoptile. In Experiment 2, the growth is inhibited when the tip

of the shoot is cut.

C ii) Auxin stimulates growth even when the tip is covered but it cannot pass through aluminium to stimulate growth.

(d) The coleoptile grows straight upwards.

(e) (i) To stimulate the growth of adventitious roots

 (ii) To stimulate the development of fruits without fertilisation, i.e. parthenocarpy

PEPERIKSAAN PERTENGAHAN TAHUN 2012-III

6(a)(i)	Process Y = ultrafiltration A process whereby: F1 – water and solutes from glomerulus  being forced to filter through the membrane of Bowman’s capsule F2 -  by the high hydrostatic pressure F3 - forming glomerular filtrate  that contains water, glucose, amino acids, urea, mineral  salts and other small molecules
(ii)	F1 -   less efficient in filtration of waste products and excess water in blood plasma P1-    as a result, urea uric acid/ creatinine / salt concentration will be increase P2 -   increase the blood pressure Suggestion : F1 -   use haemodialysis machine F2 -   to replace the function of kidney;  to filter all the waste product and excess water.
(b)	F1 – Glucose reabsorb by facilitated diffusion into blood capillary E1 – Glucose needed by our body F2 – Acid amino reabsorb by facilitated diffusion E2 – Acid amino is needed for body growth / tissue repair F3 – Plasma protein is a big molecule and cannot move via membrane plasma. E3 – Plasma protein is still circulating in blood capillary. F4 – Urea is secreted substances and cannot move back to blood capillary E4 – Water is reabsorb by osmosis and the concentrate of urea increase. F5 – Sodium ion is move back to blood capillary via active transport E5 – Sodium is importance for maintain the blood pressure.
7a)(i)	Muscle cell respiration / Q Yeast fermentation / P  1  Aerobic respiration / with O2  Anaerobic respiration/ without O2  2  Involves respiration enzyme  Involves respiration enzyme // zimase  3  Produces water, CO2 and energy  Produces ethanol, CO2 and energy  4  Occurs in the mitochondria  Occurs in the cytoplasma  5  Produces a lot of energy / 2880 kJ / 36 ATP per molecule glucose  Produces very little energy / 150 kJ / 2 ATP per molecule glucose  6  Glucose is completely oxidised  Glucose is not completely oxidised
(ii)	During vigorous activity, 1. more blood is sent to the muscles 2. so that oxygen supply to the muscles is increased 3. The heart beats faster 4. to deliver more blood, hence the pulse rate increases After some time during the activity, 1. respiration takes place anaerobically 2. because the maximum rate of oxygen uptake is less than oxygen demand. 3. there is build up of lactic acid 4. After activity, a period of recovery is needed to provide the oxygen 5. so that the lactic acid can be oxidized 6. and to provide the energy for the recovery of the muscles
b)	Similarities Fish / M Human / N  F1 : Both possess large surface area for gaseous exchange  E1 : Filaments  Alveoli  F2 : Both possess very thin surface gaseous exchange  E2 : Thin filaments // single cell, therefore rate of diffusion is higher  E2 : Thin alveoli // single cell, therefore rate of diffusion is higher  F3 : Both respiratory organs have extensive blood capillary network  E3 : faster transportation of respiratory gases  E3 : faster transportation of respiratory gases  F4 : Both possess respiratory surfaces which are constantly damp  E4 : More gases can dissolve  E4 : More gases can dissolve  F5 : Both use muscles to change pressure in respiratory organ, thorax and mouth  E5 : Possess muscles attached to the mouth and operculum  E5 : Possess diaphragm and intercostals muscles  F6 : Both possess system whereby oxygen is transported to the body tissues by blood vessels  E6 : Closed blood circulatory system  E6 : Closed blood circulatory system Differences  F7 : To ensure sufficient and continuous supply of oxygen  E7 : Water flow prevents gills from sticking  Rings of cartilage in trachea to avoid from collapsing  F8 : Position of organs to ensure that respiratory surface would not dry out E8 : Surface for gaseous exchange is outside the body since fish lives in water  Surface for gaseous exchange is inside the body to avoid dehydration
8(a)	(i) Glucose P1 : Excess of glucose in the blood is converted to glycogen and stored in the liver P2 : In the liver , if glucose level in blood is low glycogen is converted to glucose P3 : Excess of glycogen is converted to lipids by the liver P4 : Reaching the body cells, glucose is oxidized to release energy in cellular respiration (ii) Amino acids P5 : In liver , synthesized of plasma protein from amino acids P6 : In liver excess of amino acids ( cannot be stored in the body but) undergo deamination process. P7 : Urea is then eliminated by the kidney   P8 : In body cells , amino acids is used to synthesise new protoplasm and repair of damaged tissues   P9 : In body cell , amino acids is used to synthesise enzymes/antibodies/hormones  (iii) Lipids P10 : Excess lipids is stored in adipose tissues P11 : Phospholipids and cholesterol make up the plasma membrane                                                                                                                   Any 10
(b)	Total energy value is 5250+1500+2400+2400+750+2500+400+600=15800kJ
	P1 :  The menu is not a balanced diet // does not contain the 7 classes of food in appropriate ratio P2 : Menu is highly rich in carbohydrates and fats // no vegetables and lack of vitamins  // Higher energy intake compare to energy requirement for a girl aged 15 Consequences P3 : Constipation P4 :  lack of  fiber, faeces moving to slowly through the colon P5 : Scurvy P6 : lack of vitamin C  //any other vitamins deficiency with explanation P6 : Obesity P7 :  increase in body weight drastically due to energy requirement is less then energy intake P8 : Diabetes mellitus  P9 : excess of glucose contain in blood , food is highly rich in carbohydrates P10 : Arteriosclerosis P12 :  fats deposited in the lumen of blood vessel P13 : Heart attack P14 :  blockage in the coronary artery // Any other cardiovascular diseases with explanation
9a)	P1 : Farmers use fertilizers that usually contains nitrates/phosphate P2: Fertilizer/animal waste which contain nitrate/phosphate may washed out in water when it rains/leaching/run into the lake. P3: Algae/green plant in the lake grow faster (when they are supplied with extra nitrate/(phosphate) P4: (they may grow so much) that they completely cover the water. P5: block out the light for plants growing beneath them. P6.Photosynthesis rate reduced P7:Dissolve oxygen also reduced P8: Plants  on the top of water and beneath water eventually die. P9: Their remains are good source of food bacteria //bacteria decomposed the dead plant rapidly//bacteria breed rapidly P10:The large population of bacteria respires, using up oxygen ,so there is very little oxygen left for other living organism P11: BOD increased P12: Those fish which need oxygen have to move other areas or die                                                                                                                  Any 10
(b)	Negative/bad effects 1. Expose soil to soil erosion// loss of nutrients//loss of water     catchment area 2. Cause increase in atmospheric carbon dioxide 3. Deforestation causes the removal and thinning of the soil layer due     to exposure to wind and air. 4. The bottom of river is silted by eroded soil. 5. Landslide occurs as the top layer of soil crumbles. 6. Loss of habitats. 7. Loss of thousand species of flora and fauna due to the loss of     habitats. Positive/good effects 1. Increases job opportunities among villagers. 2. Improves the infrastructure such as new roads. 3. Increases the economic level of the villagers by selling logs.

PEPERIKSAAN PERTENGAHAN TAHUN 2012-II

5(a) (b)    c ) d) e) f)

Pain receptor                                                                                                            P1 - When an impulses arrives in the axon terminal P2-  it stimulates (synaptic) vesicles to move towards and bind with         the presynaptic membrane P3 -The vesicles fuse / release the neurotransmitter into the synapse P4 -The neurotransmitter molecules move across the synapse to the       dendrite of another neurone P5 -Stimulated to trigger a new impulses which travels along the        neurone M  : Sensory receptor // finger tip N  : Effector // muscles tissues 1. Accomodation of the eye 2. Production of saliva 1. The nerve impulse will not be sent from afferent neurone to the     effector 2. The effector / muscles will not contract 3. The hand will not be removed immediately from the needle.

PEPERIKSAAN PERTENGAHAN TAHUN 2012-I

No.	Marking criteria
1a)(i) (ii) b)(i) (ii) c) d)	W : Red blood cell/erythrocyte Y  : Xylem W : To transport oxygen Y :  To transport water and mineral ions from the roots up the leaves Nervous system F : control / coordinate activities of the body E1 : detect stimuli E2 : transmit electrical signals / nerve impulse E3 : to muscle / gland / effector                                               F1 : have large number E1 : to provide large surface area F2:  cells in tissue X is one-cell thick E2 : to increase diffusion / osmosis rate. E2: have a higher concentration of solutes than the water in surrounding soil                                                                                                F : Herbicide contains active respiratory poison / toxic E1: denatures the respiratory enzymes E2. which stops cellular respiration E3 : no production of ATP. E4 . Active transport of the ions cannot take place in the absence of ATP
2a)(i)      (ii) b)(i) (ii) (c) d)(i) (ii)	Mitosis Because the cell cycle /mitosis occur in skin cell /somatic cell F : Q is metaphase E1 : Chromosome align at metaphase plate/equator of cell E2 : spindle fibres fully formed E3 : attach to centromere of the chromosome                                                                                                      P1: To ensure new cells produced are identical in chromosomal number. P2: To ensure the sister chromatid can separate / move to opposite poles                                                                                                    -Chromosomal number (4) = 1 mark -Chromosomal behavior/correct diagram = 1 mark -Label (at least 2) = 1mark Cloning / tissue culture F : large numbers of clones can be produced E1: within a short period of time / any time E2 : clones inherited good characteristic E3 : example on good characteristic /resistance to diseases/ fast growth rate / large fruit
3a) b)(i) (ii)  (iii) c)(i) (ii) d)	Biotic components: Producer, Consumers, plant, fish, tadpole (any 2) Abiotic : Temperature, pH, light intensity, soil, rock, water (any 2) Plant/Hydrilla à larva à fish à bird C1 : 4 trophic levels C2 : Sequence and position of organism in pyramid is correct. Get rid of the bird from the habitat C1 : 10% X 1500 kJ C2 : = 150 kJ P1- lost to atmosphere as heat energy P2- used to decompose dead matter (by decomposer) P3 -used to carry out metabolism reaction in cells P4- respiration P5- excretion P6- defaecation                                                                                                    F : deforestation / logging / open burning E1 : extinction / destroy of flora / fauna E2 : loss of biodiversity E3 : disruption of food chain/web E4 : Land slides / soil erosion / water pollution / flash flood
4a)(i) (ii) (iii) b) c) d)	-Follicle Stimulating Hormone/FSH -To stimulate the formation of follicles in the ovary F1-Undersecretion of hormone W inhibits Q from the pituitary gland F2-Ovulation is delayed/does not occur F3-Oversecretion of hormone W stimulates secretion of hormone Q F4-Ovulation occur earlier ·      16th - 22nd day : Y is formed, hormone X is secreted, endometrium thickens ·      23rd - 28th day : Y degenerated, the level of hormone X declines resulting in menstruation P1 : protect the foetus by absorbing shock P2 : protects foetus from physical damage P3 : allow movement of the foetus                                                                                                     F : N secrete progesterone to stimulate / induce the thickening endometrium E1 : infection caused N not to secrete progesterone E2 : endometrium are no longer thicken // endometrium break down so, foetus is aborted.                                                                                                     P1: HCG stimulates ovulation. P2 : ovum / secondary oocyte is released from the ovary to fallopian tube. P3: ovum fuses with sperm in fallopian tube forming a zygote. P4: corpus luteum secretes progesterone. P5 : progesterone maintains the thickness of the uterine wall/ endometrium P6: the thickness of the uterine wall enables implantation to occur. (3)