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OCR Biology F212 Revision [3rd June 2013] (Now Closed)

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Primary Secondary
Slow Fast
Produces Symptoms No Symptoms
Pathogens enter for the 1st time Pathogens enter for the 2nd time
Activates B and T lymphocytes Activates Memory Cells

Good answer. Could also mention that more antibodies are produced in the secondary and that there is a shorter delay time.

Reply 741

Gotzz

Original post by OHK567

Define Ex Situ Conservation (2 marks)

Conservation that takes place outside of the species natural habitat.
(I don't know if that's enough for 2 marks? Maybe I should give an example...)
For example, in a zoo.

Reply 742

Gotzz

Original post by flygerianmc

em wait am so amylopectin is branched but not because of 1-6 bonds? i thought glycogen only contained 1-6's for quicker energy release. and em anyone gimme a quick run down on there structure and functions plox

I think it is because of 1,6 bonds. It's just that starch is also made up of amylose, which is straight, so the final structure is therefore less branched than glycogen's.

Reply 743

Gotzz

Original post by otrivine

will I not get the 4 marks, thought that was enough

I don't really know what the mark scheme would be looking for, but it's best to write down everything you can think of to be safe :tongue:

Reply 744

OHK567

Original post by Gotzz

Conservation that takes place outside of the species natural habitat.
(I don't know if that's enough for 2 marks? Maybe I should give an example...)
For example, in a zoo.

Yeh that is 2 marks the main thing to put down is outside the species' natural habitat

Reply 745

otrivine

Original post by Gotzz

I don't really know what the mark scheme would be looking for, but it's best to write down everything you can think of to be safe :tongue:

oh ok

Describe why kidneys cannot retain high concentration of glucose (3)

Reply 746

Gotzz

Original post by otrivine

oh ok

Describe why kidneys cannot retain high concentration of glucose (3)

Wow that's kinda hard.
Because glucose is soluble so it is constantly being used in respiration?
I have no idea :redface:

Reply 747

otrivine

Original post by Gotzz

Wow that's kinda hard.
Because glucose is soluble so it is constantly being used in respiration?
I have no idea :redface:

Because there is a high concentration of glucose, the glucose cannot be held in the kidney and so is excreted out of the body in the form of urine and so leads to an indication if person is diabetic

my turn :smile:

Reply 748

own

I don't believe non-reducing sugars tests have come up, anyone?

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Reply 749

Gotzz

Original post by otrivine

Are we meant to know that? :eek:

Describe an experiment to measure the change in concentration of a reducing sugar. (7)

Reply 750

Gotzz

Original post by own

I don't believe non-reducing sugars tests have come up, anyone?

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June 2012, Q4dii

Reply 751

wndms

What is Passive artificial immunity? It says you get injection with antibodies but that's clearly active...

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Reply 752

MedMed12

Original post by Gotzz

Are we meant to know that? :eek:

Describe an experiment to measure the change in concentration of a reducing sugar. (7)

but about kidney is A2 stuff :wink:

so you didnt need to know it to get the marks but it may be on the markscheme

Reply 753

Munrot07

Original post by Gotzz

Are we meant to know that? :eek:

Describe an experiment to measure the change in concentration of a reducing sugar. (7)

We aren't meant to know that :P thats F214 :smile:

an A2 question

Reply 754

Gotzz

Original post by MedMed12

but about kidney is A2 stuff :wink:

so you didnt need to know it to get the marks but it may be on the markscheme

Original post by Munrot07

We aren't meant to know that :P thats F214 :smile:

an A2 question

Good, got all panicky :redface:

Reply 755

Sam_1996

Original post by Gotzz

Are we meant to know that? :eek:

Describe an experiment to measure the change in concentration of a reducing sugar. (7)

-set up 5 soloutions each with different concentrations of glucose.(2,4,6,8,10 mMol per dm^3)
-each soloutions should have the same volume of glucose and same volume of Benedicts soloution.
-have excess Benedicts soloution
-Add all 5 soloutions to a water bath at 80 degrees and keep them in there for 10 mins
-soloution will change from blue to red with reducing sugars
-remove the soloutions and filter out the precipitate
-then add each soloution into a colorimeter and measure the transmission
-measure transmission of water as a contrast
-a greater transmission means a greater concentration of reducing sugar.

(edited 10 years ago)

Reply 756

own

Original post by Gotzz

June 2012, Q4dii

Oh, shame more unlikely now, but its a easy question for a lot of marks xD

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Reply 757

Gotzz

Original post by wndms

What is Passive artificial immunity? It says you get injection with antibodies but that's clearly active...

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Passive artificial is injection of antibodies.
Remember that active is always when the body makes the antibodies itself, due to an activation of the immune response.

Reply 758

Munrot07

Original post by otrivine

will I not get the 4 marks, thought that was enough

Also you can't mention anything about day 31, you have no idea what day the secondary response will occur, what if the person isn't infected again for 50 days after the original infection