A level Biology: Post your doubts here!

[kareem22010]

I think you would get 3 or full marks. You should've also mentioned about condensation.

This is what I wrote...maybe it can help.
View attachment 59556

okay, thank you so much
can you help me out and see another little doubt of mine? i just wanted to see if i can check the markscheme pretty well or not.

my answer:
the antibody has a variable binding region which is complementary to a specific antigen. it is a globular protein with peptide bonds to from a primary structure and hydrogen bonds to form a-helix and b-pleated sheets.

how many points would my answer earn?

 

[My Name]

okay, thank you so much
can you help me out and see another little doubt of mine? i just wanted to see if i can check the markscheme pretty well or not.
View attachment 59557 View attachment 59558
my answer:
the antibody has a variable binding region which is complementary to a specific antigen. it is a globular protein with peptide bonds to from a primary structure and hydrogen bonds to form a-helix and b-pleated sheets.

how many points would my answer earn?

Welcome.
One thing to remember is that the words underlined in the MS SHOULD be there in your answer.
I think about the alpha- beta thing it's a bit too much.
'Variable region is the antigen binding site.' would be better than saying 'variable-binding' region,I think.
So I think 2 for sure...not 3 maybe.
But do leave this question here so maybe others can answer it too.

Okay people out there?

 

[kareem22010]

Welcome.
One thing to remember is that the words underlined in the MS SHOULD be there in your answer.
I think about the alpha- beta thing it's a bit too much.
'Variable region is the antigen binding site.' would be better than saying 'variable-binding' region,I think.
So I think 2 for sure...not 3 maybe.
But do leave this question here so maybe others can answer it too.

Okay people out there?

that's weird, i thought i will get 3 marks for points 1,2 and 4 because i said both variable (point 1)& binding region ( point 2) and complementary to antigen( point 4). isn't this is the way you should count the marks?

 

[My Name]

that's weird, i thought i will get 3 marks for points 1,2 and 4 because i said both variable (point 1)& binding region ( point 2) and complementary to antigen( point 4). isn't this is the way you should count the marks?

Yes,thats right.
I did say you can get 3 maybe.

 

[kareem22010]

Yes,thats right.
I did say you can get 3 maybe.

ow, i see. but let's make it 2 marks to be safe( although it might sound inaccurate)
one last doubt for today( the same type of doubt):
Describe the structure of a chloroplast. [9]
My answer: it is a biconvex disc with a diameter of about 7 um. it is surrounded by a double membrane. each chloroplast contains thykaloids, which is arranged into grana and a stroma which contains lipid droplets and ribsomes. the grana contains atp synthase for manufacutre of ATP. the grana is arranged into light harvesting clusters.

how many marks should i get for my answer?

 

[My Name]

ow, i see. but let's make it 2 marks to be safe( although it might sound inaccurate)
one last doubt for today( the same type of doubt):
Describe the structure of a chloroplast. [9]
My answer: it is a biconvex disc with a diameter of about 7 um. it is surrounded by a double membrane. each chloroplast contains thykaloids, which is arranged into grana and a stroma which contains lipid droplets and ribsomes. the grana contains atp synthase for manufacutre of ATP. the grana is arranged into light harvesting clusters.
View attachment 59560
how many marks should i get for my answer?

Even I have these sort of doubts.
Id say this is good!
Why didnt you say something about pigment. Just saying...Chloroplast would definitely remind me of the word pigment.

 

[kareem22010]

Even I have these sort of doubts.
Id say this is good!
Why didnt you say something about pigment. Just saying...Chloroplast would definitely remind me of the word pigment.

actually, i rarely think of the word pigment and lol, my teacher gave me 4 out of 9 for my answer. i am not sure whether she is wrong about it or not.

 

[My Name]

actually, i rarely think of the word pigment and lol, my teacher gave me 4 out of 9 for my answer. i am not sure whether she is wrong about it or not.

Maybe because question says describe...she expected more text? 4 is less...now even I feel tensed. <.<
Did the question ask you to draw also?
Btw when there is space and you think you can draw nicely.Then with your explanation you can draw a diagram.

 

[My Name]

actually, i rarely think of the word pigment and lol, my teacher gave me 4 out of 9 for my answer. i am not sure whether she is wrong about it or not.

Hooo this is a sample answer from a file I downloaded here from XPC.
I think it always has some extra points. XD Which is good since I forget somethings..
Anyway I thought maybe it might help.
There is also a diagram from the revision guide.

Allah help us all!

 

[kareem22010]

Maybe because question says describe...she expected more text? 4 is less...now even I feel tensed. <.<
Did the question ask you to draw also?
Btw when there is space and you think you can draw nicely.Then with your explanation you can draw a diagram.

i am very lazy to draw.why would you feel tense?

 

[My Name]

i am very lazy to draw.why would you feel tense?

Bio is the subject where I feel doubtful about if I will get marks for my points or not.
Sometimes there is just too much answer space and I feel blank. :/

 

[kareem22010]

View attachment 59561
Hooo this is a sample answer from a file I downloaded here from XPC.
I think it always has some extra points. XD Which is good since I forget somethings..
Anyway I thought maybe it might help.
There is also a diagram from the revision guide.

Allah help us all!

i saw this answer before i wrote my first answer so, i decided to write a short answer and see if i can gain all the 9 marks. do you think my answer was worthy of about 9 marks ?

 

[My Name]

i saw this answer before i wrote my first answer so, i decided to write a short answer and see if i can gain all the 9 marks. do you think my answer was worthy of about 9 marks ?

If not 9 then 8 NOT FOUR at least.

 

[kareem22010]

Bio is the subject where I feel doubtful about if I will get marks for my points or not.
Sometimes there is just too much answer space and I feel blank. :/

by the way, i have seen your name before. aren't you the same woman who fried me on the "fight fight fight" thread?

 

[My Name]

by the way, i have seen your name before. aren't you the same woman who fried me on the "fight fight fight" thread?

Yes, haha it's me.Well I guess karma is working it's magic. XP
I have fever now.

 

[kareem22010]

Yes, haha it's me.Well I guess karma is working it's magic. XP
I have fever now.

karma will never take over my vengeance

 

[My Name]

karma will never take over my vengeance

>.<

 

[drowning-in-studies]

How do you do question 22? The table is confusing
Answer is B

 

[Rizwan Javed]

How do you do question 22? The table is confusing
Answer is B

When there's thyamine in the nucleic acid, there's no uracil and if there's uracil, there will be no thyamine.
So from the table it is quite clear that when there's Base C there's no uracil. And when there's Uracil there's no base C. This shows that the Base C is thyamine. You know that thyamine is complementary to Adenine. So from the table look for the Base whose's percentage values are closely equal to that of Base C. And that Base whose values match with those of C is Base B. So the answer is B.

 

[drowning-in-studies]

Ribosomes consist of two subunits, each containing rRNA. An analysis of all the 70S ribosomes
from a single cell of the bacterium, Escherichia coli, showed that there were:
• 38 000 rRNA molecules
• 2 main types of rRNA molecule
• 19 000 copies of each type of rRNA molecule
How many 70S ribosomes were there in the E. coli cell?
A 9500 B 19 000 C 38 000 D 76 000

How do you do this calculation? btw, Answer is B