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cn u post da MS too i think i can help u
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AS Biology P1 MCQs Preparation Thread
- Thread starter Soldier313
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Net Primary Productivity is the rate of production of organic food after allowing for that lost via respiration by plant.
So rate at which energy is lost via respiration = 5000 kJm^-2year^-1
Total = 1000,000
5000/1000 000 x 100
= 0.5 %
amylase will break down the amylose part of starch into its monomers, which are glucose molecules...and these are reducing sugars...this happens when the reaction takes place. The test for reducing sugars is the Benedicts test. And gives a positive result, a brick red ppt, with reducing sugars so the answer is A, hope that helps
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any one there?
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need hlp in octber 2003 mcqss 16,, and 6
MAY 2004: mcqs 36,, 32,, 24,, 16,, and 4
MAY 2004: mcqs 36,, 32,, 24,, 16,, and 4
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october 2004 mcq 32, 24, 17, and 5
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PLEASE HELP SOMEBODY PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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PLEASE HELP!! PLEASE PLEASE
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HELP
32 - antibodies in plasma actually means that they are antibodies against that blood group, so if the antigens of the blood group enter the body, the body will generate a response against that blood group.
for example...Blood group A has antibodies to B, or antibodies against B....so it cannot take blood from B
In the question they are saying which blood groups can receive blood from A.
see the blood groups which have no antibodies against A....that is B and O
the blood groups that can safely receive blood from A are the ones with no antibodies to generate a response against A....which are A and AB so the answer is B.
32 - 2 membranes of the cells of the alveolar wall
2 membranes of the endothelial cells of the capillary
1 membrane of the RBC
see the picture...
24 - it says the protein contains all the types of amino acids, and there are 20 types of a. acids.
so the minimum number needed will be 20 since each tRNA is specific to one amino acids.
16 - it says the molecules are too big to pass through.....it means neither through the lipid bilayer nor through the transporter proteins. so eliminate all the processes which involve the passage of molecules 'through' the membrane...the one left is endocytosis. Although endocytosis involves the inward extension of the membrane but nothing passes through.
4 - lysosomes are the organelles that contain hydrolytic enzymes, so see the option with the largest activity of lyssomes. which is C
Attachments
The rate of enzyme catalysed reactions in human cells is regulated.
Which of the following may be involved in such regulation?
1 a change in enzyme concentration
2 a change in substrate concentration
3 inhibition by the final product of the reaction
A 1 only
B 3 only
C 1 and 2 only
D 1, 2 and 3
the answer is D and i chose C. why inhibition by the final product of the reaction?
Which of the following may be involved in such regulation?
1 a change in enzyme concentration
2 a change in substrate concentration
3 inhibition by the final product of the reaction
A 1 only
B 3 only
C 1 and 2 only
D 1, 2 and 3
the answer is D and i chose C. why inhibition by the final product of the reaction?
16 - it the question it says the enzyme concentration is constant....
initially the rate of the reaction increases because there are free molecules of enzymes and es complexes form.
After some time at X....all the active sites are occupied....so increasing the substrate wont make a difference. and so the no of enzyme molecules are the limiting between X and Y...
6 - ok this will change with the size of the print of your paper...
the ACTUAL size of the line is 35 micrometers.
measure it with the ruler to get the size of IMAGE.....
now MAGNIFICATION = IMAGE / ACTUAL
measure the size of one mitochondrian
use the formula again ACTUAl = IMAGE / MAGNIFICATION
hope this helps
Q23) it's DNA code.. while DNA code is same as tRNA code, only difference is the T and U.. So, the code will be exactly the same but change T to U.
Q19) the stage that will begin from X is anaphase. Look at X.. the distance doesn't change right, cuz it's in metaphase. the next stage will be anaphase. distance between centromeres of chromosomes and pole of spindle will decrease cuz chromosomes will get nearer to the opposite pole. distance between centromeres of sister chromatids will increase because between a sister chromatid, will be separate to opposite poles.
Hope it helps.
thanks a ton
the explanation of 3 is to do with the "control of metabolic pathways"....the final product sends a negative feedback (inhibition) to the starting enzyme...n the production of the product is stopped/inhibited .
Thaaaanks =D
http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s07_qp_1.pdf
please explain questions 3 and 4
please explain questions 3 and 4
the elastic fibres and elastin that the alveoli contain are they both the same thing in the alveoli. do they both have the funtion of stretching and recoiling the arterioles >??
another thing does anybody has a good explanation of the meselson Dna experiment in which they put DNA in caesium chloride or something?
another thing does anybody has a good explanation of the meselson Dna experiment in which they put DNA in caesium chloride or something?
Yes the elastic fibres/elastin, do have the same function in blood vessels.
You may find the video at the following link helpful in understanding the DNA experiment: http://highered.mcgraw-hill.com/sit.../chapter14/meselson_and_stahl_experiment.html