WJEC AS Biology BY1 - Thursday 21st May 2015

Any one to the part b essay?

Reply 21

Original post by lewbarty

Wrote about immobilised enzymes a bit and then like it can detect small traces- in medicine and forensics wbu?

-accurate, rapid, detects small concentrations in a mixture of substances, quantitative not qualitative.. I also mentioned the use of immobilised enzymes and some advantages, although I don'tknow if I would get any marks for stating advantages of immobilised enzymes

Reply 22

lewbarty

Original post by Eddiemaiden

-accurate, rapid, detects small concentrations in a mixture of substances, quantitative not qualitative.. I also mentioned the use of immobilised enzymes and some advantages, although I don'tknow if I would get any marks for stating advantages of immobilised enzymes

Basically said same as you :smile:

I think there might be one mark or two thrown in for the immobilised enzymes because I guess they are part of the biosensor

Reply 23

VickyImrak

Original post by lewbarty

Wrote about immobilised enzymes a bit and then like it can detect small traces- in medicine and forensics wbu?

I did that ten marker as well, what did you say for the blood glucose bit?
For the advantages I said it's specific/accurate, fast and sensitive(detects X in small concentrations).
I also stated some of the advantages of using immobilised enzymes such as: they can be reused, the function in a wider range of pH and temps and may be added/removed when necessary ect. But for the first bit I said that the enzymes are immobilised in a matrix with an electrode, the blood is run through the glass columns and everytime a substrate is broken into product, the transducer receives a signal, and the signal quantity is proportional to the amount of glucose.
I don't know what it is about WJEC biology exams but they just seem so abstract and weirdly specific, but in a bad way...

Reply 24

알파카

12

Original post by Eddiemaiden

I did! What did you say the advantages were?

Didn't ask me but I'll reply anyway.
1) Can detect a specific molecule from a mixture.
2) Can provide precise quantitative data.
3) Can detect the specific molecule even at low concentrations.

Reply 25

Original post by lewbarty

Basically said same as you :smile:

I think there might be one mark or two thrown in for the immobilised enzymes because I guess they are part of the biosensor

Yeah probably! They don't deduct any marks at AS level so I guess the more information the better.. More stuff to mark!

Reply 26

VickyImrak

Original post by Eddiemaiden

Yeah probably! They don't deduct any marks at AS level so I guess the more information the better.. More stuff to mark!

Do they deduct marks in A2 WJEC Bio exams? :O

Reply 27

Original post by DistantTraces

Didn't ask me but I'll reply anyway.
1) Can detect a specific molecule from a mixture.
2) Can provide precise quantitative data.
3) Can detect the specific molecule even at low concentrations.

That's what I put! What did you write for the water potential question?

Reply 28

Original post by VickyImrak

Do they deduct marks in A2 WJEC Bio exams? :O

Yes, so I've been told :frown:

it's kind of annoying since the questions are becoming more and more ambiguous!

Reply 29

Dolphinflips

11

Original post by lewbarty

What questions I'll see if I can help

Hi is it possible you could write all the ones you remember, because I really need some reasssurance much appreciated.

Reply 30

PensAndPaper

3

Hey I am in A2 no they don't deduct marks. But next year for the new AS and A2 syllabus they will do. But it won't apply to you because you will still be in the year of the old specification

Reply 31

알파카

12

Original post by Eddiemaiden

That's what I put! What did you write for the water potential question?

Do you mean the one about the solute potential being -1120kPa or something like that?
1) Something along the lines of osmosis occurred down a water potential gradient until the water potential of the cell and external solution became equal because the cells were left in solution.
2) Incipient plasmolysis was reached where 50% of cells were plasmolysed and water potential = solute potential.
3) Water potential of cell = solute potential of cell = solute potential of external solution = -1120kPa or something like that.

I could have gone about it completely the wrong way though. :tongue:

Reply 32

joeteeeeee

I think it was pretty standard but some of the questions were proper weird, like that question for example, and for the first question they didn't actually explain fully what you had to do

Reply 33

알파카

12

Original post by joeteeeeee

I think it was pretty standard but some of the questions were proper weird, like that question for example, and for the first question they didn't actually explain fully what you had to do

You just had to put a letter in each box didn't you? For the first question, I mean. I thought that one was fairly straightforward.

Reply 34

dilushi98

that was the hardest paper they've ever made !

Reply 35

joeteeeeee

Original post by DistantTraces

You just had to put a letter in each box didn't you? For the first question, I mean. I thought that one was fairly straightforward.

But at the top of the collumn it said Letter (s)
Yet in the question it didnt say you might have to put more than one letter in the same row and there were 7 marks for 6 rows?

Reply 36

Mr rump

Unofficial mark scheme anyone?

Reply 37

wobobobob

Is anyone going to put an unofficial mark scheme up done by a teacher so I can see where I've gone wrong?

Reply 38

Mr rump

Original post by DistantTraces

Do you mean the one about the solute potential being -1120kPa or something like that?
1) Something along the lines of osmosis occurred down a water potential gradient until the water potential of the cell and external solution became equal because the cells were left in solution.
2) Incipient plasmolysis was reached where 50% of cells were plasmolysed and water potential = solute potential.
3) Water potential of cell = solute potential of cell = solute potential of external solution = -1120kPa or something like that.

I could have gone about it completely the wrong way though. :tongue:

I put at 0.4 solution was isotonic and there was no net movement in or out of cell as there were equal turgid and plaamolysed cells,at 0.4 Solution was -1120 hence that was it

Reply 39

Ceriidwen