How was Biology Paper 42 MAY/JUNE 2017?

[student2]

What do you think will the grade threshold be?
Which question did you find tough?
Well, it was lengthy..

wht do u think the threshold will b?

 

[HELLNO]

wht do u think the threshold will b?

68-70 maybe
You tell?

 

[student2]

68-70 maybe
You tell?

i cn agree wid u..bt i wish it was much lower...i messed it

 

[Metallic9896]

Han phir concern banta hai thora lekin gt will be rlly low so i still maintain you're set.
About the coenzyme thing, i googled what you said and yeah mene bhi pyruvate hi likha thaa pehle, but acetate direct react karta hai here's the source (https://en.wikipedia.org/wiki/Acetyl—CoA_synthetase). I guess dono sahi hain

Yeah let's just hope gt remains low. All the best to you too! And yes it's confusing because in your link the equation has acetate and coenzyme A at the left hand side but on here (https://chem.libretexts.org/Core/Bi...ism/Catabolism/Pyruvate_Dehydrogenase_Complex) it has pyruvate and coenzyme A at the left hand side. Wonderful. Cambridge hi bataye ga ab kya sai hai cause both make sense. It would be darn funny if the mark scheme says: Pyruvate OR Acetate XD

 

[HELLNO]

i cn agree wid u..bt i wish it was much lower...i messed it

Ohh, hopefully you didnt miss it! What did other people in your centre say?

 

[student2]

Ohh, hopefully you didnt miss it! What did other people in your centre say?

i did :/
sm said it was ok.. sm hard.. bt i think it was easier thn sm other yrs..

 

[HELLNO]

i did :/
sm said it was ok.. sm hard.. bt i think it was easier thn sm other yrs..

Ohh :/ You missed the A* or the A?
Yeah it was, especially for section B

 

[darks]

so according to posts above, variant 41 guys, was around 68 gt tough this is so relateable to m/j 2014 where p42 had 56 gt and p41 had 68 gt. History might repeat itself

 

[HELLNO]

so according to posts above, variant 41 guys, was around 68 gt tough this is so relateable to m/j 2014 where p42 had 56 gt and p41 had 68 gt. History might repeat itself

I have just had a group talk with my friends, and most of them found it hard, others said it was just lengthy with long answered questions... Lets hope for the best

 

[AvgStudent]

Most of the students in my center found variant 41 to be difficult and lengthy so i think the boundary will be similar to v42 because v41 didn't have much repetition and had a lot of analysis and just general knowledge. And for people who did v41, what did you guys answer for why algae photosynthesizes faster in polyp than when its free?

 

[comeback]

I also got 12:3:1 ratio but i think i wrote black:brown:white. Well another mark gone. Or am i right? I think white was 1...

the question said white was common so how would it be 1

 

[samanja]

I think it was co2 and pyruvate

acetylCoA + B
wasnt this the question?
and if so then it is suppose to be oxaloacetate, right?

 

[techgeek]

acetylCoA + B
wasnt this the question?
and if so then it is suppose to be oxaloacetate, right?

it was link reaction, just two things happen during link reaction, as far as I remembered. The pyruvate is decarboxylated and dehydrogenated. Dehydrogenation was already shown so it had to be decarboxylated before entering Krebs cycle, that means CO2 out.

 

[darks]

More than 24 hrs are gone.
So simpsons index of diversity 0.622.
Microarry question (mark my answer. I wrote in like 10-20 seconds in a hurry at the end.)
Microarrays have probes for many known alleles on it. When the alleles that need to be identified added to the microarray, hybridisation occurs between the probes and alleles and color given. If any probe of allele to be identified, not on the microarray, no color is given. (Something like this i wrote) please mark me.. I think 2/4

 

[Panicgirl1516]

Hi, if I got a 92 in AS what do i need in A2 to get an A*?

 

[darks]

Hi, if I got a 92 in AS what do i need in A2 to get an A*?

Around 100/130

 

[samanja]

More than 24 hrs are gone.
So simpsons index of diversity 0.622.
Microarry question (mark my answer. I wrote in like 10-20 seconds in a hurry at the end.)
Microarrays have probes for many known alleles on it. When the alleles that need to be identified added to the microarray, hybridisation occurs between the probes and alleles and color given. If any probe of allele to be identified, not on the microarray, no color is given. (Something like this i wrote) please mark me.. I think 2/4

i added some extra like- mRNA is collected and reverse transcriptase is used to make cDNA. PCR was used to get more copies of cDNA and was heated to get single stranded cDNA. Dipped in to microarry and allowed to hybridise. It was washed and laster scanner was used..

BTW i wrote the whole thing in the last 5 mins

 

[techgeek]

More than 24 hrs are gone.
So simpsons index of diversity 0.622.
Microarry question (mark my answer. I wrote in like 10-20 seconds in a hurry at the end.)
Microarrays have probes for many known alleles on it. When the alleles that need to be identified added to the microarray, hybridisation occurs between the probes and alleles and color given. If any probe of allele to be identified, not on the microarray, no color is given. (Something like this i wrote) please mark me.. I think 2/4

yes I think I got the same index of diversity.
But I think I wrote the answers to 3 significant figures instead of 3 decimal places. :/
In microarray, I wrote there are probes on the chip that have complementary bases to those that are on the DNA ( which are at risk)
so complementary base paring occurs between the DNA and probes, those DNA that cause the risk, if they are present, will bind to the probes at chip so they can be identified using computer software.
didn't you mix up that when they check gene expression using the microarray? not sure though

 

[darks]

yes I think I got the same index of diversity.
But I think I wrote the answers to 3 significant figures instead of 3 decimal places. :/
In microarray, I wrote there are probes on the chip that have complementary bases to those that are on the DNA ( which are at risk)
so complementary base paring occurs between the DNA and probes, those DNA that cause the risk, if they are present, will bind to the probes at chip so they can be identified using computer software.
didn't you mix up that when they check gene expression using the microarray? not sure though

i think i did make a mess in this question. Maybe 2 marks for probes/ hybridization i don't know if the examiner will be good enough to give me that

 

[darks]

-Fill in the blanks were easy for me, Antidiuretic hormone (ADH), posterior pituitary gland, negative feedback are the 3 answers i remember right now remind me the rest if u remember.

-The labeling question the upper one was efferent. glomerulus, i labelled on of the capillaries in the network of capillaries. for podocytes i labelled the wall of bowman's capsule facing the glomerulus..

-For first 5 mark q. numbers in brackets is where i am giving myself marks... tell me if i am right.. i wrote lactic acid produced(1) during anaerobic respiration (2) the hydrogen ions from lactic acid are responsible for lowering the PH of blood (3) after exercise (running in this case) when blood oxygen levels start to come back to normal, the lactic acid is transported to the liver (4) where it is converted to glucose (5) or stored as glycogen (6)

Please if you remember more q's and answers, post them!