8/19/2019 HKCEE - biology - 2000 - paper I - A.pdf http://slidepdf.com/reader/full/hkcee-biology-2000-paper-i-apdf 1/4 .." ~PI..eBD 2000 CE Biology Paper I Marking Scheme FOR TEACHERS' USE ONLY Marks rz.",l-t'O (i) The cells of A and the cells of the foetus are fonned by mitosis of the zygote "".""'" (ii) (1) (2) female I A spennca"ying an X chromosome I fused with an egg, which always contains an X chromosome ".'.'" I to fonn a zygote I offspring with two X chromosomes. '... I thus resulting in a female foetus (iii) There are 3 chromosomes 1 / an extrachromosome s present (iv) The foetus may be expelled out of the uterus I miscarriage ' I (v) ) ) ) any ) Blood from A to the foetushas higher oxygen content higher nutrient content lower carbon dioxide content lower urea content (accept other correct answers) Total: 10 marks ,( .(b) (i) Tissue A is .palisade mesophyll issue B is .spongy mesophyll I 1 (ii) (iii) Number of chloroplasts n region 1 s 20; while that n region 2 is 12 I Ratio of chloroplast density n region 1 to that in region 2 is 5:3 I ,: " 0 o. '_0. his allows."thc eaf to carry out pho~synthcsis at a higherrate 1 because issue A has a higher ~ensityofchloroplasts 1 and it is located in the upper ayer of the leaf :. 1 so its cells are under direct illumination I can receive more sunlight than the cells oftissueB 1 Effective communication (C) 11 (iv) Put the stem ofa leafy shoot in a dye solution for some time ~..~ ut cross sections of the stem and the leaf """' ".""""'" Examine the sections under the microscope ell type C would be stained by the dye ' Total: 12 + 1 marks -.( I. (c) (i) Oxygen in the tidal air diffuses through'theresidual air '..." ""'... 1 and dissolves in the water film lining the air sac 1 It then diffuses across he walls of the air sacand he capilla[): nto the blood... 1 I Effective communication (C) i I (I) The volume of tidal air will increase .' '..' ".'...""."...'.'.'." 1 (2) The oxygenuptake in the blood becomes aster I (ii) (iii) becausehe distanceof diffusion of oxygen rom the tidal air) to the water film is reduced ) or because he surface area of the air sac for diffusion of ) anyone 1 oxygen s increased ) Particles Tar deposit on tii~ ~all of the air ~c 1 thus reduce he rate ofdiffiisionofoxygen ..., 1 (accept other correct anSWers) ..". .,: .,1,:... '~ '. .:' Total: 8 + 1 marks ;"'---:-:i -;':J:~~;::.~ .1-:;; ,;~,~:;.;~j~:~~.~.-.',~-;-~-;-;-.b;:.:; " ~~_.. ' ' ..;, '.' ,. 20OO-CE-Brn ":. .,.. two
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8/19/2019 HKCEE - biology - 2000 - paper I - A.pdf
2. (a) (i) The daily energy intake of Jane is 6620 kJ """ '" I
which is less than her daily energy requirement I
Thus she has to consume I mobilize the fall food reserve in her body : I
~t;o ~~:;;:=~~~~h t ,
L-~=::~:~=~ .-- -l
ij) Amino acids are broken down in the liver I
to form carboh~drafC a part without nitrogen (and urea) ".'" '.'.' I
which will be oxidized/used in respiration to release energy I
(iii) anaemia '."" """'" "." ". I
(iv) Rub a piece of ham on a filter paper m translucent spot will remain after drying I
Immerse the paper in an organic solvent and the spot will disappear 1 any
OR one
Add alcohol to a piece ofham and obtain a clear solution m set
Add water to the clear solution I
The solution will turn milky 1
" .A + I marks
.(b> I
(i)
-
(ii)
.u..I: au
F ro m I t o S u ni s o f l g ht i nt en s y , t he s z e o f t he p up i d ec re as es
w h increasing lght intensiyowever, when the lght intensy is above S unis
t he s iz e o f t he p up i w r em ai n u nc ha ng ed w h i nc re as ng l gh t i nt en si yh is re sp on s e h elp s to p rev en t ex ce s s ve lg h t e nte rin g th e e y e. . . ' "o th at th e lg h t-s en s iv e c els o f th e re tin a ma y n o t b e d amag edg ht-se n si iv e c els / p h oto rc ce p to rs -+ s en s ory n e u ro ne / o pt ic n e rv e
-+ associatinn neurnn.c in .-+ motor neurone / nerve -+ iis muscle
( I f : ma rk fo r e a ch te nn ) Ded u c I f : mark i th ere is n o a r ro w s ign .ecause al the lght entering the eye is absorbed by the retina and the choroids a resul no lght is refleced out of the eye through the pupi
(iii)
3
I
iv)
I
Total: 9 marks
Advantage:
The chanceof pollination fertilization is higher )
Lesswastage f pollen grains ) anyone I
Desirable characters of the parent are more likely to be transmitted)
to the offspring )
Disadvantage:
Lessgenetic variation (accept ther con-ect nswers) I
Remove he anthers rom the flower before heyare mature I
Use a brush o dust pollengrains of another ea flower onto the stigma of this flower I
Cover he flower with a plastic bag o prevent urther pollination ". ...' I
Effective communication (C) 1
(I) Greenpod colour s dominant o yellow pod colour I
or The allele for greenpod colour s dominant o the all~le for yellow pod colour
(2) Let G represent the allele for green pods I
and g representhe allele for yellow pods
F, Gg X Gg I
It~ It~
Gamete C(;:~~a 1
Fz GG Gg Gg gg t
' Y. "'
gree~POd: yello7 pod } I
Deduct 1 mark for leaving out the abels ofF., gameteand Fz..
Total: 11 + I marks
(i)
(ii)
( -"
(iii)
2000-CE-BIO 1-9 .-
H m~. ~ (JI.~ =~F_Q.~~~CtiERS'~~-f~gt ~'Yi.~:;-:l
8/19/2019 HKCEE - biology - 2000 - paper I - A.pdf
(I) Blood capillary2) Its wall is one-cell thick I the diameter of the lumen is
slightly greater than or similar to that of a red blood cellhe pressure of blood in A is higher than the pressure of
the fluid surrounding the muscle cellshis forces the plasma except the plasma protein out of Arawing (D): clear and accurate diagram. double line for capillary wall,
biconcave RBC "",."",.,.",.,.,."""",.,.."..,."",
Labels (L): any three of the following labels and title; '/z mark each