Higher Biology 2013

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Original post by Higher candidate

25 was B if it was the one about enzyme activity cos it decreased by half

Yeh Q25 was B not A - looked again at the paper this morning when I was less tired (at high copper concentration the enzyme was completely inhibited as it showed 100% of initial concentration) - changed the answers in my original post to show this. The correct answer was that at 2.5 enzyme activity was halved.

Also section B had around 30 marks of problem solving from a total of 80 marks in this section - this is normal for Higher - it just feels like there is more PS than there actually is when you sit the exam as you are desperate to show what you have revised.

(edited 10 years ago)

Reply 281

hiimsophx

Original post by Nessie162

It wasn't Cyanide...
the question was "Why the population of green fly caused the fall in cyanic glucoside concentration" :tongue:

And the answer I wrote was
"Because the cyanic glucoside is broken down to cyanide"

I put because the greenflys were eating the leaf surfaces, the plant photosynthesised less, causing less atp to be formed which is needed for the synthesis of the cyanic glucoside?? :redface:

im sure I've done a few questions exactly like that before

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Reply 282

CSM1996

Original post by hiimsophx

I put because the greenflys were eating the leaf surfaces, the plant photosynthesised less, causing less atp to be formed which is needed for the synthesis of the cyanic glucoside?? :redface:

im sure I've done a few questions exactly like that before

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I think it said using information from the graph... somehow I don't think you got that from the graph :smile:

Reply 283

lovechemistry

see the one where you had to tick two boxes, either W X Y Z and then like 0-2 y 2-7 y 12-18 y extraaa...what boxes did yous tick?

Reply 284

CSM1996

Original post by lovechemistry

see the one where you had to tick two boxes, either W X Y Z and then like 0-2 y 2-7 y 12-18 y extraaa...what boxes did yous tick?

I remember ticking box X and I think I put 12-18.

Reply 285

lovechemistry

Original post by CSM1996

I remember ticking box X and I think I put 12-18.

yay good! i changed it from 0-2 to that just at the end :biggrin:

Reply 286

hiimsophx

Original post by lovechemistry

see the one where you had to tick two boxes, either W X Y Z and then like 0-2 y 2-7 y 12-18 y extraaa...what boxes did yous tick?

I put 0-2 because even though 12-18 had the largest increase that was over a period of 6 years whereas if you devided that by 3 to see the increase for 2 years then it was less of that than 0-2 years but idk ):

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Reply 287

CSM1996

Original post by hiimsophx

I don't think it said per year did it? I thought it just said the greatest increase.

Reply 288

Nessie162

Wait... I though we had to tick two boxes.

Then we had to choose one which proved that GH wasn't the only factor which contributed to growth.

Reply 289

lovechemistry

it was only one box for the first one .... im sure

Reply 290

JackoGeddes

Original post by Robswilson

aww god! okay what about part b? What shows that it is resistant to the cyanide?

even though increased amounts of cyanide is being produced the population of green fly continued to increase so they weren't effected by it

this shows resistance, it was a mutation question.

(edited 10 years ago)

Reply 291

hiimsophx

I think the sqa should upload the answer scheme straight away, would clear up so much confusion :frown:

Reply 292

JackoGeddes

Original post by CSM1996

I don't think it said per year did it? I thought it just said the greatest increase.

it was just what box shows that GH has an increase in body mass

pretty sure it was 12-18 because GH increased while body mass did. the others didn't show that, as in the next box the GA mass fell even though growth increased.

same with 0-2, the gh remained constant but growth happened which didn't support the statement.

(edited 10 years ago)

Reply 293

JackoGeddes

Original post by Nessie162

Wait... I though we had to tick two boxes.

Then we had to choose one which proved that GH wasn't the only factor which contributed to growth.

one box, pretty sure it was just the one which best supported GH=bodymass increase

the next bit for not the only factor i said from 14-24 growth kept occuring but GH mass had fell rapidly in this time

Reply 294

rc16

Was light intensity a valid thing to say for the yeast variable question? I think yeast grow best in damp and dark conditions

Reply 295

lovechemistry

Original post by JackoGeddes

what did you put for the next part, where you had to tick w x y or z

Reply 296

JackoGeddes

Original post by lovechemistry

what did you put for the next part, where you had to tick w x y or z

box X i think, it was the only box that had GH increasing AND body mass increasing fully, which supported the statement GH=increase body mass

Reply 297

am16

Original post by Robswilson

aww god! okay what about part b? What shows that it is resistant to the cyanide?

i said because greenfly were still present at some levels of it, not sure if thats right

Reply 298

JackoGeddes

Original post by am16

i said because greenfly were still present at some levels of it, not sure if thats right

it was the fact that even though the plant was producing more cyanide (which would usually deter grazing) they kept increasing, so they must have been resistant.

pretty sure i wrote ''Increased production of cyanide by leaves but green fly population per leaf keeps increasing so they are resistant''