AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011

Has anyone got some sort of list that can tell me all examples of negative and positive feedback throughout all the units?

Reply 1581

cheeseisnice

Do we need to know specific things from AS/Unit 4, like could they ask how photosynthesis/respiration works?

Reply 1582

NRican

Original post by cws121

what do we have to know about gene therapy then, just thats it replaces defective genes, because thats all it says

Somatic and germ line and how Somatic is ineffective because cells die and has to be replaced etc.

Reply 1583

cws121

Original post by Vidja

Has anyone got some sort of list that can tell me all examples of negative and positive feedback throughout all the units?

(a) Negative feedback in living organisms

Topic areas for assessment of scientific content:
(1) principle of negative feedback ? departure from a norm initiates changes which
restore a system to the norm. (P)
(2) importance in homeostasis; principles of detection of change, role of receptors,
corrective response, role of effectors. (H)
(3) thermoregulation; roles of thermoreceptors and hypothalamus in detection; heat loss
and heat gain centres; sweating and vasodilatation in heat loss; vasoconstriction, hair
erection, shivering and increased metabolism in heat gain. (T)
(4) regulation of blood glucose; roles of receptors in pancreas, secretion of insulin or
glucagon; effect of insulin on surface membrane receptors/carrier proteins in stimulating
uptake of glucose and glycogenesis; role of glucagon in glycogenolysis. (G)
(5) regulation of blood water potential; role of receptors in hypothalamus; secretion of
ADH from pituitary; effect of ADH on permeability of d.c.t. and collecting duct; role
of loop of Henle in maintaining high ion concentration in the medulla; effect on urine
concentration. (W)
(6) control of ventilation; stimulation of chemoreceptors in medulla; effect on inspiration;
stimulation of stretch receptors in lungs; stimulation of expiratory cells in medulla.
(B)
(7) control of heartbeat; roles of chemoreceptors and pressure receptors; inhibitory and
acceleratory centres in medulla; effect on SAN and rate of heartbeat; effect of change
in rate on pH/pressure of blood. (HB)
(8) metabolic pathways; examples of build-up of a product in a metabolic pathway resulting
in inhibition of its formation. (M)
(9) population stability; effect of increasing competition/predation on increasing population
size and restoration of balance. (Pop)
(10) (selection ? stabilising selection resulting in constancy of species) (S)
(11) (Oestrous cycle; effect of feedback on hormone production, e.g. oestrogen on FSH and
progesterone on both FSH and LH. From Option 8)

Reply 1584

RMS184

Name all the enzymes involved with DNA in our syllabus and their function :biggrin:

Haha was looking for a synoptic essay title! :tongue:

But will just do it simply then;

DNA HELICASE - breaks hydrogen bonds between bases in transcription (causing two strands to separate
RNA POLYMERASE - joins complimentary nucloetides to 'template strand' which is present in the nucleus
REVERSE TRANSCRIPTASE - catalyses the production of DNA from RNA (for producing DNA fragments).
RESTRICTION ENDONUCLEASE - enzymes that 'cut' DNA to reveal 'blunt' and sticky' ends etc.
DNA LIGASE - used to join to backbones after restriction endonuleases have 'cut' DNA strands

Any big ones i have missed!? :tongue:

A smaller question perhaps:

Describe the sequence of events leading to the release of acetylcholine and its binding to the postsynaptic membrane.

Reply 1585

Sparkly-Star

OP

13

Original post by RMS184

Name all the enzymes involved with DNA in our syllabus and their function :biggrin:

Haha was looking for a synoptic essay title! :tongue:

But will just do it simply then;

DNA HELICASE - breaks hydrogen bonds between bases in transcription (causing two strands to separate
RNA POLYMERASE - joins complimentary nucloetides to 'template strand' which is present in the nucleus
REVERSE TRANSCRIPTASE - catalyses the production of DNA from RNA (for producing DNA fragments).
RESTRICTION ENDONUCLEASE - enzymes that 'cut' DNA to reveal 'blunt' and sticky' ends etc.
DNA LIGASE - used to join to backbones after restriction endonuleases have 'cut' DNA strands

Any big ones i have missed!? :tongue:

A smaller question perhaps:

Describe the sequence of events leading to the release of acetylcholine and its binding to the postsynaptic membrane.

That last question would be the best EVER.

Reply 1586

Flux_Pav

whats 80UMS and 120 UMS in terms of marks?

Reply 1587

cws121

Original post by NRican

Somatic and germ line and how Somatic is ineffective because cells die and has to be replaced etc.

This is what the old spec wanted you to know

In gene therapy healthy genes may be cloned and used to replace
defective genes.
In cystic fibrosis the transmembrane regulator protein, CFTR, is
defective. A mutant of the gene that produces CFTR results in CFTR
with one missing amino acid.
The symptoms of cystic fibrosis related to the malfunctioning of
CFTR.
Techniques that might possibly be used to introduce healthy CFTR
genes into lung epithelial cells include:
• use of a harmless virus into which the CFTR gene has been
inserted;
• wrapping the gene in lipid molecules that can pass through the
membranes of lung cells.

This is what our spec wants us to know

The use of gene therapy to supplement defective genes.
Candidates should be able to evaluate the effectiveness of gene therapy.

so all the things in bold we didnt actually have to know, what a waste of time!

Reply 1588

IFondledAGibbon

11

Unlike eukaryotic cells, bacterial DNA does not contain introns.
a) Suggest the advantage of transforming bacteria by inserting complementary DNA rather than a copy of the original gene.
b) Suggest one advantage of using transgenic yeast rather than transgenic bacteria to produce useful proteins.

Reply 1589

RMS184

Original post by Sparkly-Star

Haha wasn't looking for a synoptic essay title! :tongue:

But will just do it simply then;

DNA HELICASE - breaks hydrogen bonds between bases in transcription (causing two strands to separate
RNA POLYMERASE - joins complimentary nucloetides to 'template strand' which is present in the nucleus
REVERSE TRANSCRIPTASE - catalyses the production of DNA from RNA (for producing DNA fragments).
RESTRICTION ENDONUCLEASE - enzymes that 'cut' DNA to reveal 'blunt' and sticky' ends etc.
DNA LIGASE - used to join to backbones after restriction endonuleases have 'cut' DNA strands

Any big ones i have missed!? :tongue:

A smaller question perhaps:

Describe the sequence of events leading to the release of acetylcholine and its binding to the postsynaptic membrane.

That last question would be the best EVER.

Answer it then!! :tongue:

Reply 1590

Flux_Pav

Original post by IFondledAGibbon

Unlike eukaryotic cells, bacterial DNA does not contain introns.
a) Suggest the advantage of transforming bacteria by inserting complementary DNA rather than a copy of the original gene.
b) Suggest one advantage of using transgenic yeast rather than transgenic bacteria to produce useful proteins.

a) original gene contains introns whereas in complementary DNA intron not included
b)yeast respire anaerobically ? have no clue tbh

you got answers to this?

Reply 1591

Ineluctable

3

Original post by cws121

what do we have to know about gene therapy then, just thats it replaces defective genes, because thats all it says

Yes, but I'm positive that they will always use examples like cystic fibrosis or SCID. So it might be worth reading about it, although not revising what causes it etc.

Reply 1592

M.A.

Original post by cws121

so all the things in bold we didnt actually have to know, what a waste of time!

OMG. No way! The amount of times I wrote them procedures out too, memorising them! :mad:

Reply 1593

Flux_Pav

what is 80ums and 120ums in terms of marks? Ffs

Reply 1594

Sparkly-Star

OP

13

Original post by Flux_Pav

what is 80ums and 120ums in terms of marks? Ffs

http://web.aqa.org.uk/UMS/ums_converter_a2.php?id=04

Depends on the grade boundaires. Maximum you can get is 140 UMS. It is out of a 100 marks.

So 80/140 * 100 = 58/100
120/140*100 = 86/100

Reply 1595

RMS184

Original post by Flux_Pav

what is 80ums and 120ums in terms of marks? Ffs

80 UMS is about 48 marks
120 UMS is about 65 marks

Reply 1596

IFondledAGibbon

11

Original post by Flux_Pav

a) original gene contains introns whereas in complementary DNA intron not included
b)yeast respire anaerobically ? have no clue tbh

you got answers to this?

Nope

Reply 1597

sammycjones

Original post by Flux_Pav

a) original gene contains introns whereas in complementary DNA intron not included
b)yeast respire anaerobically ? have no clue tbh

you got answers to this?

original gene contains introns whereas in complementary DNA intron not included

= it goes through a method of "splicing" where the introns that dont code for amino acids are removed and only exons are remain, happens during transcription in the nucleus

cant help with the other questions :frown:

Reply 1598

kingsmod1

guys how many minutes do we have for essay, and how many mins of that should be used for planning some1 please answer???? :P

Reply 1599

alllie

hey guys! earlier someone posted an amazing document and twas about 33pages of potential synotic and poss essays (i think) but i cant remember what page it was on.. can anyone help me out and know the page number?!?! Massive thanks

AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011

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