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A2 Biology | Post your doubts here
- Thread starter hassam
- Start date
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Errors in the MarkScheme??!
43/O/N/11 Q11 b
Chiasma formation in metaphase I? Isn't it supposed to be late prophase I?
41/O/N/10 Q9 a
Males homogametic? Aren't they supposed to be heterogametic?
and finally... 43/M/J/10 Q7 c
Anaerobic respiration in yeast involves ethanal dehydrogenase? Isn't it supposed to be alcohol dehydrogenase?
So, is it me or they are really making MISTAKES???
43/O/N/11 Q11 b
Chiasma formation in metaphase I? Isn't it supposed to be late prophase I?
41/O/N/10 Q9 a
Males homogametic? Aren't they supposed to be heterogametic?
and finally... 43/M/J/10 Q7 c
Anaerobic respiration in yeast involves ethanal dehydrogenase? Isn't it supposed to be alcohol dehydrogenase?
So, is it me or they are really making MISTAKES???
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To save you some reading, if u dont know what in situ means, it just means that bacteria can do the work underground rather than having to mine the rocks first.
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I suggest that u start with the last question. I find it to be easy marks.
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mRNA is transcribed from the gene coding for insulin and there is plenty of it in the beta cells whereas DNA contains all the genes and therefore would require restriction enzymes to cut out the insulin gene.
Our teacher said the same thing, its painstakingly lengthy, however he said if you try to practice writing over and over again it will help a lot
And also give confidence in yourself.
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2.5 ATP are actually produced per 1 reduced NAD and about 1.5 per reduced FAD. Per one glucose molecule, 2 reduced NAD are produced in glycolysis, 2 in the link reaction, 6 in the krebs cycle. 2 reduced FAD are produced in the Krebs cycle. Therefore, a total of 28 ATP molecules are produced by oxidative phosphorylation in the electron transfer chain. Don't forget the 4 ATP produced by substrate level phosphorylation (2 in glycolysis, 2 in the krebs cycle). This gives a total of 32 ATP molecules.
substrate level phosphorylation is when ATP is formed in the cytoplasm and matrix (i.e. not oxidative phosphorylation where ATP is produced on the cristae)
e.g height... if the person has alleles for being tall but he doesn't get enough diet or he's going through a process of starvation, there will be less chance for him being tall.
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like you can see in ethopia their was a gene of tall height but ad their is starvation spreading hence the gene couldnt florish hence affected by the env. phenotype is short height or normal heigh people.
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i cant find the second ppr can u please attach the question ?
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yes you are right about males being hetero gametic this is a mistake i guess ..
Height of person, the genes will be switched only in the availability of nutrition.
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we can also talk about some alleles switching on at certain temperatures right? like coat color in Himalayan rabbits!
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My hand starts aching when writing the Biology test, cuz it's so long. What should I do??
oh yeahh same here!!! its so much of writing!! just take a break for 15-30 secs and also a deep breath
everything that is mentioned in the syllabus...