Edexcel A2 Biology Unit 4 (6BI04) - 15 June 2012 - Official Exam Discussion Thread!!!

Original post by Cetacea

Pollen in peat bogs can provide information about past climates. Peat is an accumulation of dead organic matter (detritus), mainly the remains of dead plants. The conditions in a peat bog are acidic and anaerobic, meaning the rate of decay of plant material in a peat bog is slowed or stopped.

Pollen grains are well preserved in peat and are useful in reconstructing past climates because:
-They are produced in large amounts
-Pollen grains are resisant to decay due to their tough outer layer
-Peat forms in layers: the deeper the layer, the older the peat
-Each species of plant has a distinctive type of pollen. Therefore by examining the pollen in the peat, scientists can determine the species of plants that lived during that time, therefore get an idea of the climate.

Scientists construct a pollen diagram based on the abundance of pollen grains in a sample. (Search on internet for lots of sample pollen diagrams).

Hope that helps.

thank you!

Reply 62

Original post by M Kh

How do you revise?
x

Original post by d_94

Do you have any notes for Unit 4 you can up-load?

Original post by This Honest

Learn info>x

Are any of doing the papers from the old syllabus for this paper? If so, which ones are you doing. I just checked on xtremepapers and there are 4A, 4B and 4C to do.....not sure which should start on :s-smilie:

Any advice could be well appreciated!

Reply 63

M Kh

OP

Original post by arnab

Are any of doing the papers from the old syllabus for this paper? If so, which ones are you doing. I just checked on xtremepapers and there are 4A, 4B and 4C to do.....not sure which should start on :s-smilie:

Any advice could be well appreciated!

Solve the qns in textbook and rev. guide.

Reply 64

heey people..im really freaking out.. as i need an A in bio... was wondering whats the best way to ace this exam.. from what year are you guys doing the past papers from ?
any tips on how to revise??

Reply 65

Original post by M Kh

Solve the qns in textbook and rev. guide.

I have already done that.....i am just doing these topic by topic questions that i found on the internet.
Any advice regarding the old syllabus?

Reply 66

Original post by aqua05

heey people..im really freaking out.. as i need an A in bio... was wondering whats the best way to ace this exam.. from what year are you guys doing the past papers from ?
any tips on how to revise??

Going through the revision guide, memorising it off by heart and then doing tons and tons of questions.....any question i can get my hands on :biggrin:

Edit : are you doing papers from the old syllabus?

Reply 67

Original post by arnab

Going through the revision guide, memorising it off by heart and then doing tons and tons of questions.....any question i can get my hands on :biggrin:

Edit : are you doing papers from the old syllabus?

yes i am

till what year do you suggest we do from ?
Which revision guide are you revising from ? I'm using cgp & the SNAB one..

Reply 68

This Honest

3

Original post by arnab

Are any of doing the papers from the old syllabus for this paper? If so, which ones are you doing. I just checked on xtremepapers and there are 4A, 4B and 4C to do.....not sure which should start on :s-smilie:

Any advice could be well appreciated!

I haven't yet but will do

Reply 69

heyy guys...
I was just thinking of this question..

Describe the roles played by the photosystems (PSI & PSII)

What would you guys say?

Reply 70

vampirerahim

Original post by arnab

Are any of doing the papers from the old syllabus for this paper? If so, which ones are you doing. I just checked on xtremepapers and there are 4A, 4B and 4C to do.....not sure which should start on :s-smilie:

Any advice could be well appreciated!

Hey listen
download this
It has questions from older syllabus that are still useful to our syllabus
compiled chapter wiseeeeee
epic stuffff

http://www.mediafire.com/?s1ctvexdb9u57xb

135 pages of ecoglogy questions :P

Reply 71

Original post by This Honest

I haven't yet but will do

which ones are you doing for unit4? 4A or 4B or 4C?

Reply 72

Original post by vampirerahim

Hey listen
download this
It has questions from older syllabus that are still useful to our syllabus
compiled chapter wiseeeeee
epic stuffff

http://www.mediafire.com/?s1ctvexdb9u57xb

135 pages of ecoglogy questions :P

I already have this but thank you anyway. Your help is well appreciated :smile:

Reply 73

heey guys

Can someone please please answer this question for me???

Describe the role of the scientific community in validating new evidence (including molecular biology, eg DNA, proteomics) supporting the accepted scientific theory of evolution (scientific journals, the peer review process, scientific conferences).

Discuss how a person's point of view might affect the conclusions they reach about actions to take on global warming

Describe the modelling of trends in global warming and the limitations of this approach

Explain how the concept of niche accounts for distribution and abundance of organisms in a habitat.

(edited 11 years ago)

Reply 74

Can someone please please help me answer this question??

Question.

Explain how changes that happen aftyer transcription can give rise to more than one protein from one gene??

Reply 75

demdil

Original post by aqua05

Can someone please please help me answer this question??

Question.

Explain how changes that happen aftyer transcription can give rise to more than one protein from one gene??

after transcription there are post transcriptional changes(also known as pretranslational changes) introns are separated, exons can be arranged in different ways, so different proteins can be made when different sections of mRNA are spliced together before translation. i didnt explain it well i guess, but you gave to study to the RNA splicing basically. The questions about that :smile:

Reply 76

Original post by demdil

after transcription there are post transcriptional changes(also known as pretranslational changes) introns are separated, exons can be arranged in different ways, so different proteins can be made when different sections of mRNA are spliced together before translation. i didnt explain it well i guess, but you gave to study to the RNA splicing basically. The questions about that :smile:

SUPER

Thanks ! i got it :biggrin:

How are you studying for this unit ??

Reply 77

demdil

Original post by aqua05

SUPER

Thanks ! i got it :biggrin:

How are you studying for this unit ??

i havent started studying yet but i will go through the book once and then do the past papers and then if i have time do the old syllabus papers :smile:

how are you studying? i guess we have the same exams (chem units 4/5 etc) .. are you finding time for this unit? :smile:

Reply 78