F215 - Revision thread 13th June 2011

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Reply 1960

How many UMS marks does everybody need for an A, i need 132, how many raw marks would i need to get?? I presume it would be quite a lot :frown:

Reply 1961

HEC14

i need 87 for the A, i THINK thats a C? :smile:

Just realised its a high D!

Reply 1962

heartskippedabeat

Original post by sickofexamz

How many UMS marks does everybody need for an A, i need 132, how many raw marks would i need to get?? I presume it would be quite a lot :frown:

It'll probably be around 60-65 marks for an A, which is 120 UMS. So maybe 70 something, it depends how hard/easy the paper is :redface:

Reply 1963

rebmu

Original post by miss-pink09

can anyone please please please tell me what i need to know for genetic engineering human insulin.
i have no clue. and i dont find the textbook useful :frown:

can someone please break it down for me

basically you just need to know how its done
first you get the source of the genetic information so mRNA which codes for the insulin protein, you then use reverse transciptase to convert this into cdna, primers can then be added to the cdna which are complementary to the sticky ends of the plasmid
plasmids are useful as bacteria actively take these up.
you cut the plasmid open using restriction enzymes , these cut the plasmid at a specific site, this is why you know which primers to add, the cdna can then bind to the plasmid, the plasmid is sealed using DNA ligase, this is your recombinant dna.
however we aren't quite done yet
you need to know which cells have taken up plasmids and which of those have a recombinant plasmid with the gene we want
so you use replica plating, basically you know the plamid i was talking about earlier you choose this carefully so it has genes for antibiotic resitance in it , which original bacteria do not, usually ampicillin and tetracycline, you then use a restriction enzyme which cuts through one of these antibiotic resistance genes, usually tetracyline, therefore if you grow colonies of the bacteria on agar, those that have taken up the plasmid will grow on ampicillin those that haven't are killed, so basically you then see which grow on tetracycline , those that grow on ampicillin but not on tetracycline are the ones you want so you takes these bacteria and let them reproduce to levels significant enough to produce industrial amounts of insulin and that's about it
think the book probably explains it clearer than me though so have a look in the cgp revision guide

Reply 1964

Kaph

Original post by heartskippedabeat

It's 480/600 for an A
420/600 B
360/600 C

The jan papers are out of 90 ums, the june ones are out of 150 and the coursework is out of 60.
Yeah, the results slip from AS will have your ums marks from last year for each module so just add them up, and from Jan if you did f214 then :smile:

A2 coursework is a bit more tricky, no one knows what the grade boundaries will be, but if you know what you got out of 40 for this year and last year, you can estimate what UMS you'll get for A2 coursework by using the ums you got from AS coursework :smile:

Thank you

Ah that's pretty cool, managed 86 in F214 in Jan, thought it was out of 100, heh.

I can't find my result form from last summer which is a pain. Ah well.

Reply 1965

DrDr

Original post by sickofexamz

How many UMS marks does everybody need for an A, i need 132, how many raw marks would i need to get?? I presume it would be quite a lot :frown:

You'll be needing over 70% raw, maybe 75-80% (going by past results) to be safe.

Good luck! :smile:

Reply 1966

heartskippedabeat

Original post by Kaph

Thank you

Ah that's pretty cool, managed 86 in F214 in Jan, thought it was out of 100, heh.

I can't find my result form from last summer which is a pain. Ah well.

Ahh well done!
What grade did you get last summer? If you know whether it was low/mid/high for that grade you can kind of work it out :smile:

Reply 1967

CoventryCity

Original post by CoventryCity

Also can somebody link to me some good resources or give me a brief summary of what we need to know for DNA probes and sequencing the genome. I understand about PCR and electrophoresis but don't understand the chain termination method or sequencing the genome using BACs

^^

Thanks for any help

Reply 1968

HEC14

Quick description of Ammonification?
Pleasee :smile:

Reply 1969

thecookiem0nster

Original post by CoventryCity

^^

Thanks for any help

The process of DNA sequencing:
1. DNA is mechanically sheared into random fragments

2. Microsatellites are used to determine the order of the fragments (location of microsatellites is already known)

3. The fragments are cloned
Fragments are placed into bacterial artificial chromosome
Transferred to E.Coli by transformation
E.Coli are cultured to form a gene library

4. The clones are sequenced using the chain-termination method (Sanger sequencing method)
A very large amount of single stranded DNA is taken from the clone libraries and restriction endonucleases are used to form shorter strands from the long strand
DNA primers, DNA polymerase, normal nucleotides and modified nucleotides that terminate DNA strand elongation are all required for this process
The short DNA strands are divided into 4 separate sequencing reactions, containing all four of the standard nucleotides but only one type of the modified nucleotides
The modified nucleotides lack a 3’OH group, so they terminate formation of the sugar-phosphate backbone
DNA polymerase produces a stand that terminates when a modified nucleotide is added to the end of the chain
Over a period of time, the modified nucleotides form a termination at every point on the strand
The four reactions are separated into four different wells on a gel electrophoresis
Electrophoresis is used to separate the mixtures, producing 4 lanes of different termination nucleotides. The position of modified nucleotides is determined by exposing x-ray film to the electrophoresis gel

5. The chain-termination method is repeated using different restriction endonucleases and the overlapping regions are identified by a computer. The computer assembles the data to form the full genome of the organism

Reply 1970

thecookiem0nster

Original post by HEC14

Quick description of Ammonification?
Pleasee :smile:

"When a plant dies, an animal dies, or an animal expels waste, the initial form of nitrogen is organic. Bacteria, or in some cases, fungi, convert the organic nitrogen within the remains back into ammonium (NH4+), a process called ammonification or mineralization" - Wikipedia

The bacteria/fungi it is talking about are just decomposers

Reply 1971

Kaph

Original post by heartskippedabeat

Ahh well done!
What grade did you get last summer? If you know whether it was low/mid/high for that grade you can kind of work it out :smile:

Thankouu

Well I got a U last summer, didn't sit the paper due to illness aha. So took a load of exams in Jan, but managed 120 in F212. Nicely scraping the A hehhh.

I seem to remember my ISAs not being anything special, and in F211 I didn't do brilliantly, but I have the Jan marks.

Think I need around 130UMS for the A. Possssssibly doable, but I doubt it. On the bright side, only 67UMS for the B.

What grade are you after? I can't wait to get bio done, free up the majority of my brain again.

Reply 1972

greenford

You know the marking for F215 is it similar to OCR chemistry..like they only mark the first five or six points if its a 5 mark question???

Reply 1973

Bullit

Original post by greenford

You know the marking for F215 is it similar to OCR chemistry..like they only mark the first five or six points if its a 5 mark question???

That cant be right. If you write 10points but only 5 of the points are in the markscheme you can still get 5/5 no matter what order you write them in

Reply 1974

heartskippedabeat

Original post by Kaph

Thankouu

Ahh okay, hahah nice :tongue:

I loved the f212 paper in jan, everyone kept saying it was really hard :s-smilie:

i got a U in f214 in jan though :colondollar:

That's pretty good, especially 67 for a B! :smile:

I reallllly want a B overall, so I'd need 105 ums in this, and 65 in my module 4 resit :redface:

but i only need a C in biology to get into uni, so that's 75 ums in this module only :smile:

Reply 1975

joestevens2092

Can somebody just go over Genome sequencing for me please

Reply 1976

Luke0011

I think i just worked out that I need around 90 UMS to get an A, that can't be right can it? :P haha!
Seems like hardly anything!
Especially with the scaling up!

Reply 1977

thecookiem0nster

Original post by joestevens2092

Can somebody just go over Genome sequencing for me please

Reply 1978

tesha_al

Original post by wilsea05

1)wet soils make the conditions for bacteria in the soil anaerobic - as no oxygen is available nitrates must be taken up to use as a source of oxygen.
2)Pioneer species that can tolerate high levels of salt etc occupy just above the high water mark - these species stabilize the ground by producing nitrates and making the ground firmer with their roots. Secondary species can now succeed these as the environment becomes more tolerable - community of organisms changes until climax community reached, e.g. a forest.
3)Insecticides contain toxic compounds which could leak into rivers when it rains, and produce knock on effects for the environment - could cause problems if organisms other than insects e.g. birds eat the crop. Biological pest control is more natural and doesn't have knock on effects for the environment? (i dunno im rambling haha)
4)Succession is a directional change in a community of organisms over time, which starts at an uninhabitable area, where pioneer species first occupy, stabilizing the area until a climax community is reached.
5)Continuous culture involves the constant addition of nutrients and oxygen, and removal of waste products and products - chlorella is a form of algae - starter culture added to fermenter, pH temp O2 and nutrient levels at optimum for growth - remove algae at intervals
6)Explant taken (usually) from tip of shoot of plant to be cloned. This is steralized, and then placed on a growth medium to promote cell division, but not cell differentiation - this produces a mass of undifferentiated cells called a callus. Callus is broken up into smaller fragments, and these are placed on another growth medium which promotes shoot growth, then transferred to another growth medium to promote root growth. These plants are then planted in soil in a green house to acclimatize to conditions.

what do i get out of 27? i hate all the ecology stuff :frown:

haha

Well done. lost 2 marks on the continuous culture but everything else fine.

Reply 1979

intellectual1

June 2010

Flow diagram of main stages of Cheese - milk, protein, casein
Cheese making Biotechnological process
Pasteurisation
Enzyme Rennin and milk
Rennin advantages
Rennin 8 marker - Bacteria genetically modified to produce Rennin

17 marks were on Biotechnology

Genotypes Phenotypes, Gene Interaction, Coding, Mutation, Hetrozygous, Genetic Diagram, Chi-Squared test, Gene Coding, Synthesis of Polypeptides

32 marks were on Genetics...

Dopamine DDR4 more genetics 18 marks...

20 marks on Ecosystems, Populations and Sustainbility which included Timber.

13 marks were on Plant growth hormones, germination of seeds, graph interpretation...

Quite clear about half the of the paper was focused on Module 1 Cellular Control...with quite a few marks on Biotechnology and Ecosystems, Populations and Sustainbility with 13 marks on the Plant Growth Hormones topic...

January 2011

Artifical Selection, Selective Breeding, Variation, Mutation, Enzyme Lactase, Lac Operon 16 marks!

Muscle - nervous system and hormones control voluntary, involuntary, cardiac, Human Brain, Fight or Flight Essay a huge 24 marks, 1/4 of the paper was on this...

Plant growth, ecosystems, primrary producer, biomass 14 marks

Fermentation Pencillin 14 marks

Genetic Engineering and Gene Cloning PCR 17 marks

6 marks for defintions in module 3 and 4 :eek:

along with 3 marks each for examples and description of Habituation, Operant Conditioning and Social Behaviour in Primates and its importance. 15 marks.

About half the paper was on Biotechnology Module 2, with hardly any of Module 1 Cellular Control. Quite alot of marks on Module 3 and 4 accounting for about a third of the marks.

June 2011

Lots of Module 1 with slightly less Module 2, and quite a few questions on Module 3 and 4.