F215 - Revision thread 13th June 2011

HAHA! unless you have seen the paper already or know everything inside out...NOBODY! let us hope it is a paper with low grade boundaries :biggrin:

Grade boundaries so far have been just 65 and 60 marks for an A!!!

Reply 2101

intellectual1

3

20 HOURS REMAIN UNTIL THE EXAMINATION WHICH SHALL DECIDE YOUR FUTURE FIRM OFFER OR NO OFFER OR INSURANCE OFFER OR RESIT

Although its closer to 14 hours considering a person needs 6 hours of sleep... :eek:

Reply 2102

ksahnan

8

Original post by hellosarah

What do we need to know about cyclic AMP, apart from it activates proteins by altering its 3D structure...? Anything elsee??

If its an enzyme, if you can say that by changing the 3D shape its shape is a better fit for its complementary molecule/substrate

Reply 2103

Jhyzone

13

Original post by hellosarah

What do we need to know about cyclic AMP, apart from it activates proteins by altering its 3D structure...? Anything elsee??

Applications - the lac operon:
Lactose binds to repressor protein changing its shape.
Lactose is the (inducer) or the (first messenger) xD

Another one is on the sliding filament model.
Ca 2+ ions binds to troponin, changing its shape allowing the myosin head to bind with actin filaments and bend.

Reply 2104

heartskippedabeat

10

Original post by greenford

So whose actually feeling prepared for this exam?

Not at all :frown:

I'm trying to be positive though haha, so yeah it's gonna be great!!!! ... :/
You?

Reply 2105

Bintang

Original post by 786girl

please could somone outline the points about NERVIUS SYSTEM its the only topic i feel very weak at. help!!

The nervous system is split into the CNS (the brain and spinal chord) and the PNS (the neurones that send impulses to and from the CNS)

The PNS can be split further into the somatic nervous system (voluntary muscles) and the autonomic nervous system (involuntary muscle) which is made up of the parasympathetic nerves (helps relax the body eg when sleeping) and the sympathetic nerves (prepares body for times of stress and danger)

Reply 2106

Srikmeister

Original post by thecookiem0nster

Grade boundaries so far have been just 65 and 60 marks for an A!!!

True, but it also means you've got to be able to pick up those 65 or so marks to get the grade, and in Unit 5, it is no easy thing. Having said that though, many people get an A in biology so it is certainly possible!

Reply 2107

DrDr

Original post by thecookiem0nster

The ocr book really makes it confusing. I was confused too

Gibberellins cause stem elongation.

Heres the evidence:

In the same species, some plants are dwarfs and others are tall plants. It was found that tall plants had more gibberellins than dwarfs. A mutant plant without the gene for creating gibberellin did not grow tall. But when one of it’s branches were grafted onto a normal plant, the graft grew tall. Therefore, gibberellins are responsible for stem elongation

I thought it was actually to do with having the specific allele that could break down GA20 to GA1 (but yes, higher GA1 conc's in plants = greater stem elongation).

Eg Dwarf plant has loads of GA20 but no "Le" allele, and therefore cannot break down GA20 to GA1 and grow. (has a recessive "le" allele)

Tall plant has GA20 and GA1 because it has GA20 to begin with and the "Le" to break it down.

However if you graft the tall plants lateral stem onto the dwarf plant, it receives the "Le" allele and instantly starts to grow. :smile:

Reply 2108

amyyy24

11

Original post by intellectual1

x

I haven't even done any past papers properly!

Reply 2109

fahimak

hey does anyone know the grade boundries for f215 specimen paper?

Reply 2110

heartskippedabeat

10

Does anyone think abscission's likely to come up? :/y

Reply 2111

thecookiem0nster

Original post by 786girl

please could somone outline the points about NERVIUS SYSTEM its the only topic i feel very weak at. help!!

also just as a general question; has there ever been a time when u have WORKED VERY HARD and put it a lot of effort into revising and still get a grade with which u were disappointed? or does hard work always pay off?

LOL You mean nervous system :smile:

Someone on page 104 did a nice flowchart. The nervous system is split into the central and peripheral. Peripheral contains the somatic and automic components.

The central nervous system is just the brain and spinal cord. The peripheral neroucs system is all other nerves.

The autonomic component is split into Sympathetic and parasympathetic

Symathetic is stimulated for the fight/flight response. The parasympathetic returns the body back to normal. The parasympathetic brings you down like a parachute - that helps me remeber the difference between the two

I find hard work always pays off :biggrin:

Reply 2112

DrDr

Original post by intellectual1

20 HOURS REMAIN UNTIL THE EXAMINATION WHICH SHALL DECIDE YOUR FUTURE FIRM OFFER OR NO OFFER OR INSURANCE OFFER OR RESIT

Although its closer to 14 hours considering a person needs 6 hours of sleep... :eek:

I hope I'm not the only one who feels quite annoyed whenever you do this. I manage to get into a nice rhythm of work and relaxation and ask a few questions on this thread, and then get that.

Please stop.

Reply 2113

thecookiem0nster

Original post by DrDr

I thought it was actually to do with having the specific allele that could break down GA20 to GA1 (but yes, higher GA1 conc's in plants = greater stem elongation).

Eg Dwarf plant has loads of GA20 but no "Le" allele, and therefore cannot break down GA20 to GA1 and grow. (has a recessive "le" allele)

Tall plant has GA20 and GA1 because it has GA20 to begin with and the "Le" to break it down.

However if you graft the tall plants lateral stem onto the dwarf plant, it receives the "Le" allele and instantly starts to grow. :smile:

Thats right :smile:

The mutant plant had the homozygous le genotype

Reply 2114

rebeccalouise_92

for hardy weinburg equations, do we have to work out q squared? or will it give us everything including the eq an we just put it in...haha?

because i don't understand for the example of cystic fibrosis, how q= cfcf and q^2 =cFcf

Reply 2115

wilsea05

1

Original post by rebeccalouise_92

for hardy weinburg equations, do we have to work out q squared? or will it give us everything including the eq an we just put it in...haha?

because i don't understand for the example of cystic fibrosis, how q= cfcf and q^2 =cFcf

q^2 should be cfcf, books wrong.

Reply 2116

-Jaz-

Original post by rebeccalouise_92

right, can anyone tell me the ratios i need to know for genetics, i can remember dihibrid crosses should be 9:3:3:1 , if not it must be because of epipstasis, any others..

Dominant epistasis - 12:3:1 or 13:3
Recessive epistasis - 9:3:4
Complementary action: 9:7

Reply 2117

amyyy24

11

Original post by rebeccalouise_92

for hardy weinburg equations, do we have to work out q squared? or will it give us everything including the eq an we just put it in...haha?

because i don't understand for the example of cystic fibrosis, how q= cfcf and q^2 =cFcf

I think it's a mistake in the book, q^2 is cfcf aswell, though why they had to use 2 letters anyway is stupid.

Reply 2118

786girl

Describe the role of the brain and nervous system in the coordination of muscular movement;
?

Reply 2119

Bintang

Original post by rebeccalouise_92

for hardy weinburg equations, do we have to work out q squared? or will it give us everything including the eq an we just put it in...haha?

because i don't understand for the example of cystic fibrosis, how q= cfcf and q^2 =cFcf

q=cf (the recessive allele)
q^2=cfcf (homozygous recessive)

F215 - Revision thread 13th June 2011

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