A level Biology: Post your doubts here!

[A*****]

According to mark scheme, the impulses first reach the apex of the heart and then through the purkyne tissues...then what about those tissues which are above the apex?

 

[Minsa Fatima]

Mstudent
Can antibodies DIRECTLY kill or destroy pathogens?

They have a variable region with antigen binding site so can cause agglutination of antigns/pathogens or may result in opsonisation or act as antitoxins

 

[Mstudent]

A*****
No they can't directly or by themselves. But they can neutralize toxins, or can cause clumping of bacteria or viruses so immobilizing them making it easier for *macrophages* to destroy them

 

[Mstudent]

According to mark scheme, the impulses first reach the apex of the heart and then through the purkyne tissues...then what about those tissues which are above the apex?

It moves from P - down to apex - then moves bottom up through purkyne tissues

 

[A*****]

They have a variable region with antigen binding site so can cause agglutination of antigns/pathogens or may result in opsonisation or act as antitoxins

A*****
No they can't directly or by themselves. But they can neutralize toxins, or can cause clumping of bacteria or viruses so immobilizing them making it easier for *macrophages* to destroy them

So can we just generally write that antibodies destroy pathogens, as is written in this mark scheme?

 

[LonelyStudent]

So is everyone prepared for the Paper 4 exam?

 

[Dipim007]

nope not yet ....
revision is must so after revision ready...

 

[anastasia grey113]

So is everyone prepared for the Paper 4 exam?

yh i kind of am
tho wut r u doing today?
just revision or past papers or wut?

 

[LonelyStudent]

yh i kind of am
tho wut r u doing today?
just revision or past papers or wut?

Both

 

[anastasia grey113]

o

Both

oohhhh i guess i should do that too then
i usually watch tv and sleep a day b4 so just asked lol

 

[LonelyStudent]

What an exam I tell you! Has anyone here not done it yet?

 

[anastasia grey113]

What an exam I tell you! Has anyone here not done it yet?

yh ive done it
howd u find it?

 

[LonelyStudent]

The usual. Questions were in the same style as every paper, after 2016, out there.

 

[anastasia grey113]

The usual. Questions were in the same style as every paper, after 2016, out there.

yh true that
tho i did lose 2 marks in one question lol (wrote abt glycolysis in the one abt cancer cells using up an amino acid to make a 5C compoud *sigh*)
but the rest went well

 

[anastasia grey113]

i think the threshold will be high for this year :/

 

[sterryfox]

what did you draw for the autosomal cross like how many boxes

 

[sterryfox]

yh true that
tho i did lose 2 marks in one question lol (wrote abt glycolysis in the one abt cancer cells using up an amino acid to make a 5C compoud *sigh*)
but the rest went well

we were supposed to write about etc right?

 

[anastasia grey113]

what did you draw for the autosomal cross like how many boxes

4
wbu?

we were supposed to write about etc right?

yh true

 

[sterryfox]

4
wbu?

yh true

i did like 4x4(so like 16 boxes in total) because werent there like 4 alleles each like FG fg fG and Fg as they were the offspring of F1 generation

 

[anastasia grey113]

i did like 4x4(so like 16 boxes in total) because werent there like 4 alleles each like FG fg fG and Fg as they were the offspring of F1 generation

They said (considering there is no crossing over)
so it meant that the gametes formed were (FG) and (fg) since they didn't tend to independently assort