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

When proteins are heated to a high temperature their tertiary structure is disrupted.

How does this happen?

If I am correct, the mot obvious aspect to mention old be that a (very) high or higher temperatures, the hydrogen bonds will be the first to break.
The same applies to the ionic bonding present also.
The temperature effects the bonding of the polypeptides - normally the thing that makes up the earlier structures, such as Secondary - which would be hydrogen bonds - old be the topic of conversation. :smile:

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Reply 1321

Danny786

10

Yes pretty much so - Molecules have more kinetic energy, so they vibrate more so the tertiary structure is disrupted causing it to become more fluid

Reply 1322

kited4

Early bird gets the worm hey guys? :smile:

good luck! xx

Reply 1323

cab1094

1

Could somebody just outline the pros and cons of in situ and ex situ for me please?

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Reply 1324

Danny786

10

Ex-situ - advantages are people are made aware of conservation activities,a set policy can be framed by authorities,there is possibility of transferring a few individuals to same type of habitats miles away - so that there is a possibility of its sustenence in different lands.
Disadvantages - great amount of monitoring has to be carried out to do away with poaching & killing them.In countries with very high density of population - conservation becomes too difficult a task.
In case predators do not have enough prey,they do come near human habitations - endangering their lives & consuming domestic animals & especially human children

Reply 1325

rival_

10

Original post by scott18044

Yeah, I meant when I get out of there just before 11. :smile:

I get'cha now Scott

Reply 1326

rival_

10

Hey guys urm you know the female anopheles in each cycle of the plasmodium parasite it seems as though she has to bite the human twice?

Reply 1327

jamesmact

3

Original post by rival_

Hey guys urm you know the female anopheles in each cycle of the plasmodium parasite it seems as though she has to bite the human twice?

No. The plasmodium will be transferred to the human if the anopheles is infected for log enough, as the plasmodium will be in the saliva of the mosquito, as it is used before withdrawal of any blood as an anti coagulant :smile:

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Reply 1328

PreppyNinja

12

Original post by rival_

Hey guys urm you know the female anopheles in each cycle of the plasmodium parasite it seems as though she has to bite the human twice?

To carry the disease she has to bite an infected person.
To pass on the disease she has to bite an uninfected person.

So it is a continuous cycle.

Anyway, anybody know how DNA is replicated? It was a 6 mark question! :O

Reply 1329

Ptolemy001

Original post by PreppyNinja

To carry the disease she has to bite an infected person.
To pass on the disease she has to bite an uninfected person.

So it is a continuous cycle.

Anyway, anybody know how DNA is replicated? It was a 6 mark question! :O

Love this question! Double helix untwists. h2 bonds between bases break, dna unzips, leaving bases exposed. A free dna nucleotide comes along and binds to the exposed bases by h2 bonds and complimentary base pairing. Covalent bonds form between phosphate of one nucleotide and sugar of another to seal sugar-phosphate backbone.

Reply 1330

wingscarletx

Testing molecules:

1. Protein: Buriet Test: NAOH, CUSO4 -> wait -> Purple -> Protein present.

2. Starch: Idodine solution -> Turns black -> Starch present.

3. Lipid: Ethanol -> Shake -> Water -> Wait -> Milky -> Lipid present.

4. Sugars:
Reducing: Benedict's Test: add Benedict's raegent in excess -> Heat to near boiling point -> Red -> Strong reducing sugar.
Non-reducing: acid -> boil -> neutralise with NaHCO3 -> Benedict's Test -> So the reducing sugar test AGAIN.

5. Colorimeter aka Concentration Test: different test tubes containing different concentrations (same volume) -> good old Benedict's Test (same volume) -> Leave for 24 hours / centrifuge to get rid of precipitate -> use colorimeter to measure light absorbance of solutions -> plot a calibration curve.

Any mistakes?

Reply 1331

Onkar-M

Guys- any definitions you think may came up that haven't for a while? Really didn't learn them that well! Eek!

Reply 1332

razza!

DNA replication:

DNA Unzipped via DNA helicase enzymes
Hydrogen bonds between complementary BP's broken
Complementary bases exposed
DNA polymerase comes along
Attaches free, activated nucleotide via ATP to the exposed complementary BP's
A-T, C-G
Via semi-conservative replication
2 molecules of double stranded DNA formed

Reply 1333

Rick_095

I'll be so happy if the big 7/8 mark question is on something like conservation or a balanced diet.

Reply 1334

Ché.

Original post by rival_

Hey guys urm you know the female anopheles in each cycle of the plasmodium parasite it seems as though she has to bite the human twice?

Not quite, I don't think!
The human old have to be infected...
She'll have to extract blood from primarily for her initial meal, and the the transmission will take with the second helping in another host organism creating the damage to hepatocytes and erythrocytes.
And so it goes on!
:d :wink:

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(edited 10 years ago)

Reply 1335

cab1094

1

Similarities and differences between collagen and cellulose?

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Reply 1336

Ché.

Original post by Ché.

Not quite I don't think!
She'll have to extract blood from primarily for her initial meal, and the the transmission will take with the second helping in another host organism creating the damage to hepatocytes and erythrocytes.
And so it goes on!
:d :wink:

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Reply 1337

Ché.

Original post by Ché.

Not quite, I don't think!
She'll have to extract blood from primarily for her initial meal, and the the transmission will take with the second helping in another host organism creating the damage to hepatocytes and erythrocytes.
And so it goes on!
:d :wink:

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Reply 1338

wingscarletx

Original post by cab1094

Similarities and differences between collagen and cellulose?

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They are both...fibrous? :biggrin:

Reply 1339

razza!

Original post by cab1094

Similarities and differences between collagen and cellulose?

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Collagen:
Polypeptide Chain
35% (approx) Glycine
Fibrous Protein
3 strands linked together with Hydrogen bonds as cross-links
Covalent bonds between separate collagen molecules
As for function:
Used in tendons/cartilage/bones are made initially from collagen I think/also used in beauty treatments lol

Cellulose:
B-Glucose Polymer
1,4 glycosidic bonds #covalent
Arranged into micro, then macrofibrils
Function:
Strengthen cell walls in plants
Also indigestible by humans as we don't have the correct enzymes #activesite

Sure there's more on cellulose but that's all I can remember at this moment!!

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

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