1D
4: secrete lipase 5:secrete bile salt
2B
Absorption of nutrients by the colon is insignificant.
To see what kinds of operations the doctor will have for obese people, check here.
http://en.wikipedia.org/wiki/Bariatric_surgery3C
Only prokaryotes do not have mitochondria.
4D
Y is plant.
seed: flowering plants
cone: gymnosperms
spore: fern and mosses
5A
P does have chlorophyll. It can either be A, B, or D.
Q doesn't have fruit, i.e. no flower. It is either A or C.
R has flower. It is either A or C.
Therefore, answer is A.
6D (I got this wrong and I not sure.)
Diffusion when concentration nitrate in soil solution > that of root cells.
Active transport when concentration nitrate in soil solution < that of root cells.
7B
According to your opinions.
8A
Structure W allows movement in one plane. (If it moves in all directions, you'd better go to the hospital...) Y is synovial fluid. It doesn't produce fluid itself.
9A
alcoholic fermentation: glucose---->energy+ethanol+carbon dioxide
lactic acid fermentation: glucose---->energy+lactic acid
10A
Cialiary muscles contract/relax. Curvature of lens change.
11D
1 is lens. 2 is vitreous humour. 6 is cornea. All 3 can refract light.
12B (not sure)
A cannot kill pathogens. C and D are physical barriers. My book said saliva can kill bacteria. @@
13C
Let the dominant allele be A, the recessive one be a.
The parents have genotype AA and aa respectively.
Genotype of offspring is Aa. The dominant character will be shown.
14C
Both 1 and 2 are normal and have the normal allele. 3,4 and 6 have the disease and have the diseased allele. They must have inherited this allele from their parents. At least one of the parents have both alleles and is heterozygous. Since the diseased allele cannot express its effect in a heterozygous situation, it is recessive.
15A
Let the normal allele be D, the diseased allele be d.
Genotype of individual 5 is either DD or dd. (Genotype of 1 and 2 is Dd.)
Her husband's genotype is dd.
If she is DD, her children's genotype must be Dd. P (diseased boy)=0.5*0=0
If she is Dd, her children's genotype is either Dd or dd. P (diseased boy)=0.5*0.5=0.25
16D
A, B and C are discontinuous variation.
17B
Inner and middle layer of 1 contains living cells. It cannot help to remove metabolic waste. It absorbs ultra-violet, not infra red.
18D
3: vasodilation/vasoconstriction
4: hair erect/ lie down
5: subcutaneous fat prevent heat loss
19C
In the orginal set up, oxygen is taken in and carbon dioxide is released. There would not be any change in air volume. The carbon dioxide produced have to be absorbed to see the difference.
20A (corrected)
The frog won't produce oxygen. C and D are wrong.
Since all carbon dioxide produced are absorbed by soda lime, the rise in liquid level is caused by the oxygen absorbed by the frog.
21C
Flask A contains carbon dioxide produced by the rate through respiration. Flask B does not have carbon dioxide. All carbon dioxide is absorbed by NaOH.
22B
The air gradually gets stuffy. Concentration of oxygen drops. Breathing rate of the rate increases.
23B
From the graph. The activity of both enzynes>0 at pH=5.
24D
A: cannot draw a conclusion like that
B: at some pH values, this is not true
C: wrong reading from the graph
D: rate of activity of enzyme A> that of enzyme B at pH=4.
25A
C is wrong. B is not the reason. (What if I increase the temperature??) D is wrong because there is no control in this experiment. It is only for comparison.
26B (not sure)
W: palisade mesophyll cell (photosynthesis)
X: xylem (transportation of water)
Z: every living cell in the plant can store starch
27A
X does not have vacuole.
28C
A: an hour already...
B: it is immersion. this is not true.
D: different size does not cause such difference
29A
P: stop ovulation (contraceptive pills)
Q: prevent sperm and egg from reaching each other (condom, or spermicide)
R: prevent implantation (IUD)
30A
Both can transport the gamate.
31B
The ovary is still there. Ovulation will not be affected.
The uterus is gone. Nowhere for implantation.
The sperm cannot reach the egg becuase the uterus is gone. No fertilization.
32A
Very obvious... I just want to mention that preganacy is still possible because you can take out the sperms/ eggs first and have test-tube babies.
33C
Vessel wall of R is the thinnest while that of Q is the thickest.
34A
B: no evidence
C: wrong, it has smaller volume
D: wrong
35C
1 small tree can support many ants.
36D (not sure)
A: =_______=
B: This shows a complete cycle. However, it is very clear that energy in ecosystem is not a complete cycle (otherwise you don't need the sun.)
C: grass doesn't eat fungus...
37D
Carbon dioxide level rises. Carbon dioxide is acidic and lowers the pH. You need something to remove the excess carbon dioxide.
38A (not sure)
Decomposers break down organic substances like faeces and dead bodies into inorganic nutrients. However, I am not sure of (2).
39B
A: virus is far different from cells.
B: cannot conclude in that way.
D: cell organelles are much smaller and cannot be seen clearly with light microscope.
40C
(1) from the graph, but this cannot help in identifying P and Q.
(2) from the graph and it's a fact.
(3) from the graph (periphery= 周圍)
Need to identify the photo-receptors.... tricky question...
41C
A: Image can be formed. But no receptor there so the signal to the brain.
B: Neurones can be found at the blind spot (area X).
D: P is rods. Insufficient P= night blindness.
42D
Visual purple is a pigment in rods and this is what makes the rods work.
eye ball too long=short sightness
43B
Water bird prey on small fish. They compete for shrimp.
44C
microscopic algae -->microscopic animal-->shrimp --> small fish --> water bird
45C
A: wrong. no. of competitors reduce. no. of mussels increase.
B: wrong. no. of prey decrease. no. of small dish decrease
D: wrong. no. of predators decrease. no. of microscopic animals increase.
46C
High level of auxin level promotes growth of shoot and inhibit growth and root.
47D
(1) Higher auxin concentration on the left. Growth on the left hand side is faster. Bend to the right.
(2) Reverse of (1)
(3) Positive phototropism. Bend towards light.
48D
X: umbilical artery (from embryo to mother, deoxygenated blood)
Y: umbilical vein (from mother to embryo, oxygenated blood)
49C
At P, left ventricle contracts. Biscuspid valve closes. Semi-lunar valve opens.
50B (not sure)
(2) is to withstand the high b.p. of the aorta. Itself has no effect on the b.p.
51A (not sure)
(1) is very obvious.
(2) increases repiration rate to produce more heat. No hormone.
(3) I don't think this need hormone... For stronger muscle contraction, more glucose will be uptaked.
52A
A: in liver
B: It affects many parts of the body. (please refer to secondary sexual characteristics)
C: sex hormones are fat, not protein
D: Hormones are ductless and transported in blood.
53C
A is wrong because capillaries don't dilate (arterioles do).
B is completely wrong.
D is irrelevant.
54A
His father has XY. He is the least likely to have the disease. (All the others have XX.)
55A
B: Bacteria of the same generation won't get stronger.
C: They can't choose to mutate in a specific way.
D: similar to B
56C
This is the example used by the book to demonstrate natural selection.
57D
Fusion of gamate from the smae plant also cause variations because each gamate has different genetic make-up, although it has less variation than cross-pollination.
58C
It is wrong to say that if a disease is dominant, more people will have it. Therefore A and B are wrong. As for D, not all diseases are fatal.
59B (very unsure)
A: no, self-pollination, for example, involve one parent only.
C: It depends on the conditions of the surrounding environment.
D: No. Offspring produced by asexual reproduction have no variation. They are poorer in adapting to the environment.
60B
A is wrong. Movement of pollen grain requires the help of external agents.
C: for pollen grain, the male gamate is inside. itself is not male gamate.
D: wrong, can be either X or Y.
