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Edexcel GCE Biology Unit 5 6BI05 June 2013

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Reply 1140

Sly1

If I was in your position I would get the spec and read the fat snab book 5 times before the exam.

Reply 1141

Tomatochuckers

Original post by I Hate Edexcel

Ok, thanks! I'll try and be brisk then. :smile:

Were the questions on the pre-release difficult? And were they general or very specific to the booklet? I'm kind of scared because I don't know what to expect.

In all honesty I'm not sure because I am a wasteman and have never revised the pre-release stuff but I think I was able to get quite a few marks by looking at the text, i.e. comprehension last time I did it.

There were some questions which were synoptic though if I remember correctly.

Reply 1142

Sly1

Original post by Tomatochuckers

In how much detail do we need to learn the link reaction and the Krebs cycle?

The CGP book has it in much greater detail than the SNAB textbook does.

i.e. is this enough knowledge:

Glycolysis: Glycogen in liver converted to glucose. Phosphate added from two ATP which makes glucose more reactive. This then breaks into down two 3 carbom molecules. These are oxidised to form two molecules of pyruvate. 2 NAD take a hydrogen atom each so we then get 2 reduced NAD

Link reaction: Pyruvate is dehydrogenated and decarboxylated forming a 2 carbon compound (acetate). This then joins with coenzyme A to get acetyl coenzyme A. Carbon dioxide is released as a waste product, and coenzyme NAD takes up the 2 hydrogens

Krebs Cycle: In the Krebs cycle, each two carbon molecule of acetyl coA entering the cycle results in the production of two carbon dioxide molecules, one molecule of ATP by substrate level phosphorylation, and 4 pairs of hydrogen atoms which are mainly taken up by NAD with those being released in one particular step of the Krebs cycle being taken up by FAD.

Then I'd go on to explain the ETC and chemiosmosis

Is this enough detail?
Thanks!

For the krebs cycle you must know the each acetyl group combines with a 4c compound to form a 6c compound

Reply 1143

Tomatochuckers

Last year I did 9 hours of revision for this the night before and got 72/120 which is a high D or low C or whatever.

I was also very inefficient with my time and forgot to cover a chapter (note I had the time to do so) which a whole question came up on and so could've got higher. Don't give up hope

The problem is I don't seem to get that much better after I've revised for weeks.

Reply 1144

Killer_94

Original post by oli_G

I've tried searching the thread but can't find a link to the annotated article, can somebody help (my previous link to it no longer works :/)

Posted from TSR Mobile

https://docs.google.com/file/d/0B0MFgC4fsl2oVWFUd2tKT21WakE/view?pli=1&sle=true

Reply 1145

Tomatochuckers

Original post by Sly1

For the krebs cycle you must know the each acetyl group combines with a 4c compound to form a 6c compound

OK would you say that's all I'm really missing then? Thanks!

Reply 1146

Sly1

Original post by Tomatochuckers

OK would you say that's all I'm really missing then? Thanks!

Everything else looks ok to me. Other people will comment if there is anything important missing.

Reply 1147

I Hate Edexcel

Original post by Tomatochuckers

Ok that's cool, haha! I've revised stuff from earlier units so hopefully I should be ok. How hard it is to get an A do you think?

Thanks for the help!

Reply 1148

S-Angel

How the 3D shape of protein relates to its function?

Reply 1149

tsr1

what does calibration for time and volume mean?

Reply 1150

C94

Going to sleep late tonight, and do as much as I can to prepare. I wouldn't being doing a late nighter if it was an AM exam though.

please help ):

I swear the papers are so different to what we actually have to know -__- so much common sense involved

Reply 1153

HQazi

Original post by tsr1

what does calibration for time and volume mean?

Setting to a known amount basically :smile:

Reply 1154

HQazi

Original post by S-Angel

How the 3D shape of protein relates to its function?

primary structure - sequencing of the amino acids determine cell's fucntion. Polypeptide chains folded - bonds between them as well determine what type of protein it will become. ie an enzyme etc :smile:

Hope it helps

Reply 1155

Chris-69

Do you guys think that we'll have to describe the mitosis process for an insert question?

Reply 1156

Tomatochuckers

Guys what causes the stimulation of a neuron during the depolarisation phase in the first place?

Is it just the changes in potential differences? :s-smilie:

Reply 1157

zippy100012

Original post by Tomatochuckers

Guys what causes the stimulation of a neuron during the depolarisation phase in the first place?

Is it just the changes in potential differences? :s-smilie:

Sodium Ions (Na+) entering the neurone causing depolarisation.