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)