OCR Biology F212 (Molecules, Biodiversity, Food and Health)- 21st May 2012

-glycogen 1-4 and 1-6 glycosidic bonds, cellulose has 1-4 glycosidic bonds only
-glycogen alpha glucose sub units, cellulose beta glucose sub units
-Glycogen is highly branched cellulose is straight chained

-glycogen forms glycosidic bond and cellulose hydrogen bonds
-Glycogen is branched and cellulose is not
- cellulose is like a twisted helix

-glycogen 1-4 and 1-6 glycosidic bonds, cellulose has 1-4 glycosidic bonds only
-glycogen alpha glucose sub units, cellulose beta glucose sub units
-Glycogen is highly branched cellulose is straight chained

Not enough detail
You're right to say that cellulose has hydrogen bonds but both structures have glycoside bonds (glycogen has 1,4-gylcosidic bonds and 1,6-glycosdic bonds where it is branded) cellulose only has 1,4-glycosidic bonds.
Or that in glycogen all glucose molecules are in the same orientation and that in cellulose adjacent glucose molecules are rotated 180 degrees to each other.

so would i get how many marks out of 4?but i should get a mark for branched?

Mark scheme ^^

thanks can i have 2 really hard questions on disease chapter and 2 hard ones for biodiversity part

I'll do one for each coz I should start on my own revision, I'm just procrastinating by being on this thread in the first place (I did F212 last year )

Describe how cytokines can stimulate specific groups of B lymphocytes to divide

and describe the impotence of species evenness in determining the biodiversity of a habitat.


(sorry if they aren't hard enough)

no problem sorry for wasting your time
1) Cytokines have a specific receptor site which is complementary to the antigen and can be able to activate the B lymphocytes.
2) you are able to calculate simpson index diversity. High species evenness means a higher biodiversity. Also, species evenness is the number of individuals of each species

1) Cytokines are molecules not proteins, they don't have receptor sites they bind to receptor sites (on the B lymphocyte). They are complementary in shape to the receptor site on the cell surface membrane of B lymphocytes to stimulate mitosis of the B lymphocytes.

2) (measures), abundance / numbers, of individuals in each species ;
species evenness is more quantitative than species richness ; ora
high(er) species evenness indicates high(er) biodiversity ; ora
low species evenness indicates, dominance by / high abundance of, one / few, species ; ora
used to calculate (Simpson’s) Index of Diversity

I should have said that both were out of 3. You're not wasting my time btw, I'm wasting my own, A2 biology makes me miss all this AS stuff I used to hate.

i am doing A2 as well bio unit 4 and 5 stressing unit 5 is torture! i like unit 4 . so how many marks would i get ?

I'd give you 1/3 for the first one and 3/3 for the second. I loved unit 4, so much fun, everything I loved about Biology. I think unit 5 is just harder because there are a lot of new stuff and so many of the questions a large chunk of the questions will be application or suggest. Are you resitting this module then?

I'll do one for each coz I should start on my own revision, I'm just procrastinating by being on this thread in the first place (I did F212 last year )

Describe how cytokines can stimulate specific groups of B lymphocytes to divide

and describe the impotence of species evenness in determining the biodiversity of a habitat.


(sorry if they aren't hard enough)

yes im resting unit 2 got a C in jan 2012 lost lots of marks on biodiversity ! but i am doing unit 4 and 5 for the first time and covered both of the units in 3 months only so really scared

Describe how lung cancer is caused (12 marks)
Include in your answer 2 relevant mutagens?

woah F214and F215 in the space of one exam period, all the best of luck to you

there's no point asking me questions I sat this module a year ago, I don't even know why I'm here thanks for thinking of me though

I'm an A2 student as well; this could be a synoptic question which relates to mutations. This would be a brilliant question for F215