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

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Reply 1040

nevarsan

Suggest two reasons why it is better to store seeds rather than to store whole
plants

Reply 1041

xKaylax

Original post by kited4

but then if you think about it - people dont deliberately build on area's with high biodiversity :smile:

like national parks etc

That's what I mean, so would it be the opposite then for low biodiversity i.e. you would just build on it because there's nothing really special about it that's worth preserving?

Reply 1042

kited4

Original post by nevarsan

Suggest two reasons why it is better to store seeds rather than to store whole
plants

seeds take up less room so you can store more and they are easier/cheaper t transport.
also less susceptible to disease and stay viable longer

Reply 1043

Deziah

Predictions anyone? :-)

Reply 1044

milworthy

Original post by mastermdc

This is mostly correct. Just one minor mistake. You wrote A-T in base pairings. DNA replication involves mRNA, and so does not contain Thymine, it contains Uracil instead. So you should say A-U. Although, you'd probably get all the marks anyway

I swear DNA replication has nothing to do with RNA

Reply 1045

milworthy

Original post by nevarsan

Suggest two reasons why it is better to store seeds rather than to store whole
plants

Seeds don't take up as much space when you store them and can be stored in much larger numbers than plants, and remain viable for longer periods of time.

Reply 1046

MrMeep2580

Original post by milworthy

I swear DNA replication has nothing to do with RNA

yes you're right RNA is in protein synthesis which was already touching on in jan 2013 so i doubt it'd come up again

Reply 1047

Beni24

Original post by milworthy

I swear DNA replication has nothing to do with RNA

Yes you're correct! DNA has nothing to do with RNA. RNA is involved in proteinsynthesis :smile:

I think....

Reply 1048

ivy96

Can someone answer how microorganisms spoil food?

Reply 1049

Sam_1996

Original post by Deziah

Predictions anyone? :-)

Enzymes
Proteins
Malaria
T and B cells
Insecticide resistance
Biological classification
Conserving biodiversity
(Maybe the reducing sugar test as the experiment)

Reply 1050

MrMeep2580

Original post by ivy96

Can someone answer how microorganisms spoil food?

secrete enzymes onto the food, enzymes hydrolyse the food to break it up, the microorganism then takes in the nutrients and releases toxins onto the food.

Reply 1051

MarkProbio

Original post by ivy96

Can someone answer how microorganisms spoil food?

Don't think you really need to know the details. Mainly just that fungi secrete extracellular enzymes onto food, this is why they are saprotrophic.

Posted from TSR Mobile

Reply 1052

Deziah

Original post by Sam_1996

Enzymes
Proteins
Malaria
T and B cells
Insecticide resistance
Biological classification
Conserving biodiversity
(Maybe the reducing sugar test as the experiment)

Change enzymes to DNA and that wouldn't be too bad an exam haha. :wink:

Reply 1053

kited4

do memory cells gradually leave the blood if there is no secondary infection? so is that why we need booster vaccinations e.g tetanus every 10 years
or is that just because of mutations, so different antigens?

Reply 1054

Deziah

Original post by ivy96

Can someone answer how microorganisms spoil food?

-Bacteria secret enzymes which hydrolysis/break down molecules. So, proteins into amino acids, carbohydrates into glucose, triglycerides into fatty acids, etc, etc.
-Bacteria also secrete waste products and toxins which change the appearance, taste, smell and texture of food.

I learnt it as bacteria but I'm pretty sure you could just change it to microorganisms and it would be the same. :-)

Reply 1055

HeyMickey6

Original post by g.k.galloway

- Collagen
- Effect of pH on enzymes
- Inhibitors
- Adaptions (different types etc)
- Darwin's observations
- Why is biodiversity important
- Effects of CO
- Protein synthesis (long question)
- Emulsion test
- Cellulose maybe
- Preventing food spoilage

Just my ideas :smile:

emulsion test is highly unlikely to come up it was in the January 2013 exam

Reply 1056

nevarsan

Original post by kited4

seeds take up less room so you can store more and they are easier/cheaper t transport.
also less susceptible to disease and stay viable longer

Yeah full marks (2)

(edited 10 years ago)

Reply 1057

nevarsan

Original post by milworthy

Seeds don't take up as much space when you store them and can be stored in much larger numbers than plants, and remain viable for longer periods of time.

Yeah full marks (2)

Reply 1058

cookiess

Original post by king0617

The question is asking why its more similar to a pathogen the a parasite.

Pathogens don't take nutrition from the host similar to viruses

Parasites live on/in the host and take nutrients whilst harming the host

Yeah but pathogens DO take nutrition from the host...it says in the textbook on page 160 under ''pathogens''

Reply 1059

Deziah

Original post by kited4

I think so.
Memory cells will eventually leave the blood so that's why you need a tetanus jab every ten years.
I reckon you'd talk about mutations if you were talking about why everyone can't be given immunity to the influenza virus - seen as it mutates every year.