AQA A2 Biology BIOL5 - 17th June 2015

Reply 1000

78Saab

10

Original post by hiyaitsnikitaaa

it hurts just thinking about it

Paper was out of 75, not 100.

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Reply 1001

Thebest786

2

Original post by Thebest786

Can anyone clear up genetic fingerprinting in a nutshell, I have a sequence of steps in my notes but it's not very clear and I want to make sure im not missing anything

Anyone???

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Reply 1002

djhodnett

9

Original post by hiyaitsnikitaaa

it hurts just thinking about it

well chem unit 5 was lovely so i still have high hopes for bio unit 5

Reply 1003

hiyaitsnikitaaa

2

Original post by Ruby_1696

Can anyone dumb down the gene marker stuff. Like replica plating, fluorescent markers and enzyme markers ? Like.. Legit DUMB it down because I'm so confused :frown:

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replica plating is when genes are inserted into plasmids to be taken up by bacteria, the bacteria either take up the recombinant plasmid, a reformed plasmid or no plasmid so these need to be identified, ampicillin resistance is put into plasmids by restriction endonuclease and ligase, tetracycline is also put in, desired gene is put inside tetracycline resistance so its no longer functional, placed on agar plates, bacteria that die on ampicillin dont have resistance, bacteria that survive are transferred with a velvet pad to tetracycline plate, bacteria that die on this one have desired gene because resistance was corrupted, hipe this helps, its how i understand it and im awful at gene tech, im afraid i cant really do the others

Reply 1004

hiyaitsnikitaaa

2

Original post by 78Saab

Paper was out of 75, not 100.

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oh i didnt know, i was just trying to be helpful.

Reply 1005

Ruby_1696

9

Original post by hiyaitsnikitaaa

replica plating is when genes are inserted into plasmids to be taken up by bacteria, the bacteria either take up the recombinant plasmid, a reformed plasmid or no plasmid so these need to be identified, ampicillin resistance is put into plasmids by restriction endonuclease and ligase, tetracycline is also put in, desired gene is put inside tetracycline resistance so its no longer functional, placed on agar plates, bacteria that die on ampicillin dont have resistance, bacteria that survive are transferred with a velvet pad to tetracycline plate, bacteria that die on this one have desired gene because resistance was corrupted, hipe this helps, its how i understand it and im awful at gene tech, im afraid i cant really do the others

Thank you xxx I just have to read it a million times and it will finally get into my thick skull :smile:

God I hate biology so much :frown:

nah thanks for that. Replica plating is the hardest outta them !!!

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Reply 1006

hiyaitsnikitaaa

2

Original post by djhodnett

well chem unit 5 was lovely so i still have high hopes for bio unit 5

just holding out for nice essay questions

Reply 1007

hiyaitsnikitaaa

2

Original post by Ruby_1696

Thank you xxx I just have to read it a million times and it will finally get into my thick skull :smile:

God I hate biology so much :frown:

nah thanks for that. Replica plating is the hardest outta them !!!

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i find that one the easiest! hate restriction mapping so much and cant really remember steps for electrophoesis

Reply 1008

halcyon3

1

Original post by Ruby_1696

Can anyone dumb down the gene marker stuff. Like replica plating, fluorescent markers and enzyme markers ? Like.. Legit DUMB it down because I'm so confused :frown:

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when you've tried to insert a gene into bacteria you want to know which ones have taken it up. in replica plating you insert the desired gene into the gene for antibacterial resistance in the plasmid, so basically the gene for tetracycline. if the bacteria takes up this recombinant plasmid it wont have resistance to tetracycline anymore. because you havent tampered with the gene for ampicillin it will have resistance for that antibiotic.

basically you have three agar plates, one with all the bacteria in so you know which ones come from which colony, one with tetracycline antibiotic and another with ampicillin antibiotic. the recombinant bacteria will have resistance for ampicillin but not tetracycline, so die in the tet plate but survive in the amp plate. the bacteria with no plasmid will die in both and the bacteria with plasmid that doesnt contain the gene will survive in both. thats how you differentiate between them.

flourescent markers is just put a gene for fluorescence in all the plasmids, then insert the desired gene into the fluorescence gene, the recombinant plasmids wont glow but the others will.

enzyme markers is putting the gene for lactase into all the plasmids, inserting the desired gene inside the lactase gene. because lactase turns a certain substrate blue, the recombinant plasmids wont go blue but the others will.

hope thats helpful, I think its still kinda complicated :/

Reply 1009

ismailjan3

12

What's the difference between Restriction Mapping and Gene Sequencing? I understand that they do the same thing, but differently....(they both tell you a gene's base sequence).

Reply 1010

hiyaitsnikitaaa

2

Original post by halcyon3

when you've tried to insert a gene into bacteria you want to know which ones have taken it up. in replica plating you insert the desired gene into the gene for antibacterial resistance in the plasmid, so basically the gene for tetracycline. if the bacteria takes up this recombinant plasmid it wont have resistance to tetracycline anymore. because you havent tampered with the gene for ampicillin it will have resistance for that antibiotic.

basically you have three agar plates, one with all the bacteria in so you know which ones come from which colony, one with tetracycline antibiotic and another with ampicillin antibiotic. the recombinant bacteria will have resistance for ampicillin but not tetracycline, so die in the tet plate but survive in the amp plate. the bacteria with no plasmid will die in both and the bacteria with plasmid that doesnt contain the gene will survive in both. thats how you differentiate between them.

flourescent markers is just put a gene for fluorescence in all the plasmids, then insert the desired gene into the fluorescence gene, the recombinant plasmids wont glow but the others will.

enzyme markers is putting the gene for lactase into all the plasmids, inserting the desired gene inside the lactase gene. because lactase turns a certain substrate blue, the recombinant plasmids wont go blue but the others will.

hope thats helpful, I think its still kinda complicated :/

this helps me too! thanks for sharing :smile:

Reply 1011

sarah_7

Wasn't the paper out of 75 though in 2008? (if i'm looking at the right subject http://store.aqa.org.uk/over/stat_pdf/AQA-GCE-GDE-BOUND-JUN08.PDF)

Reply 1012

Ashdaw21

2

Original post by Ozy96

My prediction is the essay is either about DNA or ions.
Ions would be a dream come true

what would you talk about for ions essay?

Reply 1013

JulietR

5

Original post by jessiebon

Does anyone think an essay about specialised cells or hydrogen bonds could come up?

Maybe an essay about how different organisms are adapted and that could include how cells are adapted in leaves? Countercurrent flow in fish maybe?

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Reply 1014

sn4kebiteheart

2

Original post by Ashdaw21

what would you talk about for ions essay?

NA+ - synapses, action potentials, pancian corpuscles
K+ - action potentials, synapse (inhibitor)
C- - synpase (inhibitor)
CA2+ - muscle contraction, synapses
nitrates - nitrogen cycle
phosphate - ATP, DNA

Reply 1015

Ozy96

5

Original post by Ashdaw21

what would you talk about for ions essay?

I have mentioned the points on
Page 48
Post 946

Reply 1016

meganlouise_

1

Original post by Thebest786

Anyone???

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Genetic Fingerprinting:

1. Extraction - DNA synthesised via Polymerase Chain Reaction
2. Digestion - DNA cut using Restriction Endonuclease at specific sites
3. Separation - using Gel Electrophoresis. Immersed in alkali and agar gel mix, Southern blotting occurs with nylon sheet and DNA is soaked up via Capillary Action. Transfers DNA fragments in same position from gel to nylon membrane
4. Hybridisation - complementary DNA probes are inserted
5. Development - X Ray film placed over Nylon sheet, radiation from the probes allows DNA to be seen

Reply 1017

jessicasydes1

1

Original post by prophetkid

Some people said that if a paper is stolen and they produce a new paper etc. Then the grade boundaries are lower no matter what.
It doesn't make sense to me though. Anyone have any ideas?

My teacher is really high up in aqa and she said that what happened in psychology with some doing the reserve and some not is never happened before so hopefully if it happens tomorrow they'll just lower the grade boundaries overall so it's easier for us :h:

Reply 1018

Ashdaw21

2

Original post by sn4kebiteheart

NA+ - synapses, action potentials, pancian corpuscles
K+ - action potentials, synapse (inhibitor)
C- - synpase (inhibitor)
CA2+ - muscle contraction, synapses
nitrates - nitrogen cycle
phosphate - ATP, DNA

Thanks so much!!!

Reply 1019

charlottexheath

2

Original post by Thebest786

Can anyone clear up genetic fingerprinting in a nutshell, I have a sequence of steps in my notes but it's not very clear and I want to make sure im not missing anything

It's split into 5 stages:

Firstly, Extraction so you would use PCR in order to amplify DNA and produce a large sample.
Secondly, Digestion so you would use restriction endonucleases in order to produce fragments of a gene. This would be based on complimentary base pairing and would produce a specific section of a gene.
Thirdly, Separation. In this you would use gel electrophoresis in order to separate your fragments. Long fragments move shorter distances whereas shorter fragments will move further. You would then southern blot. This is blotting on nylon which would use capillary action to remove liquid from your DNA sample.
Fourthly- hybridisation. You would separate into single strands and add an Xray or fluorescent probe. This would allow you to identify the base sequence in the fifty step where you would use a filament overlay or you would use autoradiography (depending if fluorescent or Xray) to compare the structures to known base sequences.

AQA A2 Biology BIOL5 - 17th June 2015

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