>>> 1997
1) Which is the shortest route that can be taken by the blood
travelling from a leg to an arm in the human body?
A leg-heart-lungs-heart-arm
B leg-heart-lungs-liver-arm
C leg-liver-heart-lungs-arm
D leg-lungs-heart-lungs-arm
My answer is A but the book's answer is B something wrong?
<<<
Your answer A is correct.
>>> 1998
2) Which changes take place as blood flows through muscles
during a long period of exercise?
blood
temperature - concentration
of dissolved lactic acid
A
decreases - decreases
B decreases
- increases
C increases
- decreases
D increases
- increases
Why does the concentration of dissolved lactic acid
increase?
My answer is C and the book's answer is D <<<
Because anaerobic respiration (in prolonged period of exercise)
produces lactic acid.
>>> 1999
3) When is the sex of the baby determined?
A before ovulation
B between ovulation and fertilisation
C at the moment of fertilisation
D after the first division of the zygote
My answer is B and the book is C. No idea on this. o.o
<<<
Fertilization. Because only at fertilization, will the actual
sperm be identified. Some sperms carry X chromosome, some carry Y
chromosome. Eggs always carry X chromosome.
>>> 2000
4) What will be most likely to produce flowers of the same type
and colour?
A growing all the plants from seeds from one parent
plant
B growing all the plants from cuttings from one parent
C growing all the plant at the same temperature
D growing all the plants in the same light intensity
Why is the answer B instead of A? <<<
Seeds are the result of sexual reproduction and fertilization.
Even self-fertilization involves genetic recombination.
>>> 2001
5) Where is urea produced?
A bladder
B blood cells
C kidney
D liver
My answer is D but the answer is C o.o <<<
Liver beaks down excess amino acids to ammonia, which is
converted to urea, which is excreted by the kidneys as urine.
>>> 2003
6) Starch is digested to maltose by the enzyme amylase.
According to the 'lock and key' hypothesis, which is the
'key' and which is the 'lock'?
'Key' ---------- 'Lock'
A amylase ------------ maltose
B amylase-------------- starch
C starch-------------- amylase
D starch--------------- maltose
My answer is C but the book's answer is B. I thought the
enzyme is the 'lock' as it stays unchanged throughtout the
reaction????
(P.S there is another similar question to this one and the
book also choose the 'key' to be the enzyme)???? <<<
This is one part of the 'O' level syllabus that is dumb. The
"key" and "lock" are simply models, and only the SPECIFICITY of the
model makes sense. One can argue either way for which is the key
and which is the lock.
>>> 2006
7) Some organisms live in the dark at the bottom of the
seas and ,to synthesise glucose, use energy from chemicals in
the very hot water that comes out of the volcanoes.
What is a distinguishing feature of these organisms?
A Their enzymes are easily dentaured by heat.
B They do not need carbon dioxide
C They do not need to be green
D They all obtain energy only by being carnivores
My answer is B but the book's is C. I
don't quite understand this question.. <<<
They do not need chlorophyll, since there is no light to be
absorbed.
>>> OTHER QUESTIONS:
8) Is germination in syllabus? <<<
Check yourself :
http://www.seab.gov.sg/
>>> 9) When concentration of adrenaline in blood
increases, will it lead to an increase in insulin in blood? (since
there is a increase in blood glucose concentration)
<<<
Yes.
>>> 10) Some features of the plant leaves are
listed
1 hairs on lower surface
2 large surface area
3 waxy cuticle
Which features reduce water loss from the leaves?
A 1 and 2 only
B 1 and 3 only
C 1,2,3
D 2 and 3 only
My answer is B but the book's is A. Need some help..
<<<
1 & 3. Large surface area increase water loss, but bo pian,
because large surface area allows greater surface area to capture
more light and absorb more carbon dioxide, both important
for photosynthesis.
>>> Help will be kindly appreciated, Thank you all.
(Bio paper on Thursday, hopefully can catch up) <<<
Welcome. 