OCR 2010 A2 Biology Unit 2 - Control, Genome and Environment

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MG.GULED

Wow you've managed to simplify ecosystems which i find so boring into short great cards !
i wanted to ask do you think we need alot of information about drd4 receptors ad dopamine in relation to human behaviour.

umm im not sure, i havent covered that section yet (didnt listen in class so dont even have a clue what they are :eek:

), im jsut starting to cover that section now :smile:

Reply 1781

HELPME-ology

chuck111

heres the link to my revision card thread :P
u should find the june AS ones there

http://www.thestudentroom.co.uk/showthread.php?t=1289356

Thank youu yehh i found them a little while ago :smile:

hehe!
So badly saved my life!!

Reply 1782

HELPME-ology

chuck111

Yer theyre based on the spec, i basically go through every point in the specification and try to answer it as best as I can and format it into a revision card to make it easier to remember

That is actually quite amazing... must have taken you forever.. but with the standard you are answering each spec question, hopefully when i revise these they will defo helpp :smile:

Reply 1783

HELPME-ology

How do you guys revise? In terms of prioritising your day in accorandance to the amount you need to learn..
I have like 6 days till my Bio June AS exam re-sit and I haven't done any past paper questions cos I feel ithere is no point until I cover the theory of it all...
Any tips? Please do add some!!

Reply 1784

lexafish

Can anyone explain to me how meiosis 1 is different to mitosis? except for crossing over.

Reply 1785

dopeyangel101

lexafish

Can anyone explain to me how meiosis 1 is different to mitosis? except for crossing over.

the daughter cells after meiosis I are all haploid (half the original no. of chromosomes) and if I'm right in thinking, the daughter cells are not identical (there is variation) thats all i can think of

hope that helps, but probably not...

Reply 1786

TheMikester69

Why are 'starter' cultures only required for large cultures, I.e industrial batch cultures. Surely all cultures, no matter how big, require a starter culture?

Reply 1787

Ziffachan

dopeyangel101

You could also say that the daughter cells in meiosis I have two copies of each chromosome/2 chromatids joined at the centromere whereas in mitosis they have one?

Reply 1788

Emma5678

Hi
Please could someone define the term recombinant DNA?
Thank you

Reply 1789

Sakujo

I hate OCR Biology it is truly run by retards as admitted by my Biology and Chemistry teacher. My left foot could write better mark schemes, it honestly could. Guys is it me? Look at this:

Question's stem mentions a plant has narrow genetic diversity and almost always self pollinates.

Question: Why does it have narrow genetic diversity? (2 marks)

My Answer: Genetic variation doesn't occur through meiosis and fertilisation. Produces clones of itself with exact same genotype through asexual reporduction.

Mark Scheme: Self-pollination, inbreeding, limited gene pool.

Self-pollination was mentioned in the question and inbreeding usually doesn't occur as it self pollinates. I got zero for that question. :confused:

This is a joke! :mad2:

Reply 1790

Falcon91

Emma5678

Hi
Please could someone define the term recombinant DNA?
Thank you

Recombinant DNA - DNA that has been taken from 2 different organisms/2 different sources and placed into one organism/combined into one plasmid.

Im completely p'd off. Im just not sure how to revise the synoptics of this exam and i just CANT seem to revise F214 sufficiently as i keep forgetting small details, because of the fact im trying to learn so much for F215! FFS anyone else having the same problem?

Time to go try again. =/

Also @Sakujo, yes they are idiots.

Thank you x

Falcon91

Hey, i believe the same here now (just need to run through some parts), although didnt get too much done today. So lets do this > :biggrin:

Disucss some of the reasons for conservation.

Wow, another boring one... :p:

The reasons for conservation can be split into 3 catergories.
1) Ethical- All species have a right to survival and as humans we have the moral responsibility to look after them.

2) Economical reasons
- Most species have financial prospects.
- Can be used as a food source, wild species are required in order to increase the genetic vartiation, for example to breed drought tolerant, fungal resistance, or to be domesticated for food use themselves.
-Natural predators can be used as biological control agents
- Can be used for other products, like drugs for medical use.
- Maintain climate stability-prevent floods etc.
-Maintain soil conditions, nutrient cycles etc.

3) Social Reasons
- aesthetic reasons, places look nice, can generate financal income.

Reply 1793

Falcon91

ViolinGirl

Wow, another boring one... :p:

Theres not much in this syllabus that screams interesting :P

Reply 1794

dopeyangel101

Falcon91

Theres not much in this syllabus that screams interesting :P

I second that motion...

Anybody else up for dropping out and becoming a hobo?

Reply 1795

MasterJomi

Falcon91

Theres not much in this syllabus that screams interesting :P

What about the parts on the brain and the sliding filament module. :eek:

Reply 1796

dopeyangel101

MasterJomi

What about the parts on the brain and the sliding filament module. :eek:

true, actually the whole of 2.4 is interesting IMHO aside from plants, i actually hate them!!!!!

Reply 1797

ViolinGirl

Falcon91

Theres not much in this syllabus that screams interesting :P

Sorry, forgot your question!

Decribe methods of conservation. :biggrin:

Reply 1798

Falcon91

ViolinGirl

Sorry, forgot your question!

Decribe methods of conservation. :biggrin:

Ohhh...
i think i fail at remembering this part and im not sure which bit you meant so i typed part of it while using the book, now i know a flaw in my knowledge - Note i have now learnt this from heart :P

Conservation involves - reclamation of lost and damaged ecosystems in order to restore them and methods must be dynamic as ecosystems are dynamic (subject to changes).

Can be within the natural environment (in situ) such as National Parks or SSSI's.
Conservation Ex situ of endanagered species - Conservation outside of the natural environment, i.e. in a zoos and botanic gardens

-Raise carrying capacity by providing extra food
-Restrict dispersal of individuals by fencing
-Control Predators and poachers
-Vaccinate individuals against disease
-Preserve habitats by preventing or removing pollution/disruption or restriction of succession
-Movement of organisms to encourage population growth and

Something interesting eh...lets go with...explain how a muscle is stimulated at a neuromuscular junction (include what goes on in the muscle fibre too).

Reply 1799

ViolinGirl

Falcon91

Ohhh...

Something interesting eh...lets go with...explain how a muscle is stimulated at a neuromuscular junction (include what goes on in the muscle fibre too).

An impluse reaches the motor end plate, and this causes vesicles containing the neurotramitter acetlycholine to bind to the membrane, and release acetlycholine across the synaptic cleft between the sarcollema and the motor end plate. The actelycholine binds onto special receptors on the sarcollema called nicotinic cholinergic receptors, this causes depolarisation of the membrane. The depolarisation passes through the T-system and this causes the release of Ca2+ ions from the sarcoplasmic reticulum, these bind onto troponin molecules on the actin filament, and cause for the tropomyosin to move off the actin-myosin binding site...

too lazy to desribe the rest. I know it though.

Decribe the differences and similaries between synapses and NMJ.