AQA A2 Biology BIOL5 - 17th June 2015

Original post by Maryam.M

Oh I see thank you so much, and good luck for tomorrow! :smile:

your welcome :smile:

thanks you too! :biggrin:

Reply 1062

werdo1997

12

"Explain the role(s) and/or the effects of DNA in biological organisms/systems."

Is this a possible essay title? What would be a good plan?
Also, would a bit of further explanation of the Human Genome Project gain more marks in this?

Reply 1063

xSophie04x

Original post by kiwi8397

do diagrams gain marks in essays?

i don't think so but if your stuck its always worth a try. They do sometimes look at your plan if you run out of time ive been told :smile:

Reply 1064

TheRaspberry

For transcription; is it DNA Helicase which breaks the hydrogen bonds, or another enzyme?

Reply 1065

Monkey D. Luffy

7

Original post by TheRaspberry

For transcription; is it DNA Helicase which breaks the hydrogen bonds, or another enzyme?

You are correct. Dna helicase does.

Reply 1066

TheRaspberry

Could someone please quickly run through the whole SiRNA topic - really confused by it, and do not understand!

Reply 1067

Ann1234

Can someone help me with the last part please. I understand 2 and 3 hours after its 0% but why is it 80 at 1 hour after? Thanks

Reply 1068

Ann1234

Could someone explain this please

Reply 1069

caffeinefuelled

10

Original post by werdo1997

"Explain the role(s) and/or the effects of DNA in biological organisms/systems."

Is this a possible essay title? What would be a good plan?
Also, would a bit of further explanation of the Human Genome Project gain more marks in this?

Unless you get 14 marks for content, the extra 2 aren't available, so just nail the specification knowledge because it's not worth thinking about extra really. Which AS topics come up most frequently?

Reply 1070

xSophie04x

Original post by Ann1234

Can someone help me with the last part please. I understand 2 and 3 hours after its 0% but why is it 80 at 1 hour after? Thanks

just done this :smile:

look at hour 1 on the graph and extract off both lines. A is 8 and B is 2 so we know the total units is 10. so 8 out of 10 is 80%. then for the other two boxes look at the A line only and it is on 0 as there is no line so it is 0%
i got the second and third box wrong when i attempted it two hours ago but went through it and now i get it. i hope this made sense to you and helped :smile:

Reply 1071

HopefulDentist..

Original post by charlottexheath

In order to make a specific protein you can either inhbit or increase transcription or inhibit translation- which will mean that genes will be "switched on" or "switched off."

Oestrogen is a transcription factor and it will bind to DNA when it is being made into mRNA. It can fit in different ways, which means that it can either activate transcription, by allowing RNA polymerase to bind to it, or it can stop transcription, so blocking RNA polymerase from binding to it which will mean that the gene will be switched off.

thankyou!

Reply 1072

HopefulDentist..

Original post by halcyon3

transcriptional factors move from the cytoplasm to nucleus, they have a site that binds to specific regions on the DNA, the target gene thats going to be expressed. it stimulates transcription and mRNA is made.

thankyou!

Reply 1073

thegiggler

In Repolarization the potassium channel open and potassium move out while sodium channels close?

Reply 1074

caffeinefuelled

10

Original post by TheRaspberry

Could someone please quickly run through the whole SiRNA topic - really confused by it, and do not understand!

There is a big double stranded molecule of RNA that is chopped by an enzyme into little double strands. The little double strands are called siRNA. The strands of siRNA separate, and one combines with an enzyme. Because there are bases sticking out of the single strand (which is attached to this enzyme), the enzyme is lead to a piece of mRNA that has complementary base pairs to the siRNA attached to the enzyme. This ensures that the enzyme is in a position to chop up the mRNA, cutting the mRNA into small sections so it can't be translated.

Reply 1075

killmekoalabear

Does someone want to share their plans with me for possible essays? I will love you forever

Reply 1076

Maryam.M

Original post by bg9876

Just doing that now too, was about to ask the same thing, did you do the first question? Again it says cut once but two fragments? Always 1 less than I think?

Hi I found the whole of question 5 quite difficult but I think I get it now they used 2 separate plasmids for each restriction enzyme. It says that there are 2 pieces which means that they must have used 2 restriction enzymes of kpn1. Where it says one cut of kpn1 that is on the same plasmid as bamh1. :smile:

Reply 1077

TheRaspberry

Original post by smoothER

There is a big double stranded molecule of RNA that is chopped by an enzyme into little double strands. The little double strands are called siRNA. The strands of siRNA separate, and one combines with an enzyme. Because there are bases sticking out of the single strand (which is attached to this enzyme), the enzyme is lead to a piece of mRNA that has complementary base pairs to the siRNA attached to the enzyme. This ensures that the enzyme is in a position to chop up the mRNA, cutting the mRNA into small sections so it can't be translated.

Thanks!

Reply 1078

charlottexheath