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AQA BIOL1 ~ 14 May 2012 ~ AS Biology

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Reply 280

britash

Original post by coolcric321

I know I'm a bit unsure on some details, so maybe someone can clear them up? i think I've got the main points though.

You've literally hit every single point.
And I agree on the ones you dont need to know ^ x

Reply 281

britash

*this is the time when i being to panic* AHHHHH.

Right. I have all the past papers to do today,.
Question booklet
&&&&
MUST go over, heart, lung diseases then memorise all the mark scheme questions when my mum gets home from spain :smile:

Great day or what =/ ?! x

Reply 282

4MANU4EVER4

Original post by leeandrewarmstrong

I mentioned the tertiary structure being changed. The tertiary structure includes hydrogen bonds, ionic bonds and disulphide bridges.

I'm not saying your wrong.....hydrogen bonds seem to be quite popular with the aqa examiners....that's all

Reply 283

HopefulFutureMedic

Original post by iPthreefifthteen

For carrier protein all you need to know is:

- Different carrier proteins facilitate diffusion of different molecules
- Carrier proteins transport large molecules in and out of the cell
- Down a concentration gradient i.e. from high to low concentration
- the process starts by large molecule attaching to carrier protein
- The protein then changes shape
- Which releases molecule on opposite side of membrane
- it's a passive process - no energy is used

And for protein channels:

- Different protein channels facilitate diffusion of different charged particles
- Protein channels form pores in the membrane
- For charged particles
- Down a concentration gradient
- This is also passive

I hope I haven't missed anything important out :smile:

Hey thanks for these clear conscise points, i found them quite helpful :smile:

Good luck to you if your re-sitting! :biggrin:

Reply 284

4MANU4EVER4

Original post by britash

Great day or what =/ ?! x

How many past papers have u got to do?

Reply 285

britash

Original post by 4MANU4EVER4

How many past papers have u got to do?

8 I think.
Plus all my schools' booklets. Fun day :/

Reply 286

4MANU4EVER4

Original post by britash

8 I think.
Plus all my schools' booklets. Fun day :/

wow....already done my past papers....just lookin' over them....memorising all 5 markers....got to revise cellular and humoural immnuity....AAAAAGGGGHHH :argh:

Reply 287

HopefulFutureMedic

Original post by leeandrewarmstrong

I'm sure all of that stuff is wrong. Carrier proteins are used for active transport and require energy from ATP. Channel proteins are water filled channels used for facilitated diffusion.

Okay, would you care to share what points you would include.

Reply 288

. . .

Original post by na_tasha

Hi everyone hope your all ready for the exam!
I have a quite a few questions to ask so if anyone can answer any of them then please do :frown:

im just tryna make sure i firmly understand a few things..

1.) The actual definition for monoclonal antibodies?
2.)What are Fibrous proteins & globular proteins and what are their roles
3.)Do amino acids have their own FORMULA ? (eg monosaccharides are C6H12O6)
4.)What bonds hold the substrate in the active site of the enzyme
5.)What is end product inhibition ??
6.) WHY is the induced fit a better explanation that lock & key?
7.)How the sodium potassium pump works & basically everything about active transport im really confused on it! does it only carry glucose? what about water & other ions and substances.
8.)The symptoms of TB & how it infects the lungs eg post & primary infection
9.)What is myogenic?? to do with the heart
10.) The definition for IMMUNITY
11.) What are the ethical implications of vaccines?

Help with any of these questions will be appreciated x

1. Antibodies produced from a single group of genetically identical B-Cells.
2. Fibrous Proteins have long parallel polypeptide chains, usually insoluble, many have structural roles e.g. keratin in hair and the outer layer of skin, collagen (a connective tissue).
Globular Proteins have complex tertiary and sometimes quaternary structures, folded into spherical (globular) shapes, usually soluble, roles in metabolic reactions e.g. enzymes, haemoglobin in blood.
3. Amino acids have carboxyl group (-COOH), amino group (NH₂), hydrogen and a variable R are group (different for each amino acid) which determines which amino acid it is.
4. Hydrogen bonds (also van der Waals and hydrophobic interactions but you only need to know hydrogen bonds for the BIOL1 exam)
5.http://www.occc.edu/biologylabs/Documents/Homeostasis/End_Product_Inhibition.htm
6. It is more accurate the theory changed when new evidence became available. It states that the substrate not only has to be a complimentary shape to the active site but must also change the active site in the right way.
7. a)Water diffuses by osmosis which is the net diffusion of water from a less negative (0 = Pure water) to a more negative water potential (-100 water with substrate) via a partially permeable membrane.
b)Charged ions (chloride ions) and larger molecules (amino acids and glucose) diffuse via facilitated diffusion (passive process so does not require energy (ATP)).
A large molecule attaches to a carrier protein which changes shape and releases the protein on the other side, down its concentration gradient.
Charged molecules diffuse via protein channels down their concentration gradient this is also a passive process.

c)Active transport moves substances against the concentration gradient and therefore requires energy (ATP).
Carrier proteins are involved in active transport it is a bit like facillated diffusion where a molecule attaches to the protein it changes shape and releases on the other end the only difference being it requires energy because it is moving the molecule against its concentration gradient.
Co-transport protein is another way active transport is carried out. In this two molecules bind to the protein one which is moving down it's concentration gradient and one which is moving against its concentration gradient, the molecule changes shape and releases both molecules on the other end. This also requires energy because it is moving one of the molecules against its concentration gradient.
The sodium potassium pump jumps pump just moves sodium and potassium ions down their respective concentration gradient for example it moves sodium ions out of the cell membrane and potassium ions in. This requires energy in the form of ATP too.
8. Symptoms of TB include persistent cough, coughing up blood, mucus chest pains, shortness of breath and fatigue. Also fever and loss of weight due to loss of appetite.
It affects the lungs because when somebody becomes infected with the TB bacteria the immune system cells build a wall around the bacteria this is known as tubercles and the infected tissue inside the tubercles dies this damages the gas exchange system and reduces tidal volume and therefore pulmonary ventilation it can also lead to fibrosis.
9. Myogenic just means the heart contracts itself it doesn't need an outside stimulus for example for a nerve cell.
10. Resistant or protected from a particular pathogen due to having the correct memory cells.
11. Testing on animals may be considered ethically wrong.
Substances may be animal base some people think this is wrong to use animals for that sort of purpose
Vaccines have to be tested on humans but then they are putting themselves at unnecessary risk.
If there was an epidemic how would people prioritise who get the vaccine first.

Reply 289

dinosaretoocool

Original post by Alex_and_er

Still on AQA :smile:

Question Paper
http://store.aqa.org.uk/qual/gce/pdf/AQA-BIOL1-W-SQP.PDF

Mark Scheme
http://store.aqa.org.uk/qual/gce/pdf/AQA-BIOL1-W-SMS.PDF

silly me!!! :colondollar:

thanks a bunch!

Reply 290

StudentAnon

Anyone have anything (from mark schemes or your knowledge) on B/T cells and monoclonal antibodies?

Got a feeling those will come up and they're some of my worst topics :redface:

Reply 291

username570910

Has there ever been a question on T cells? I've seen some about Memory cells, but that's about it :/

Reply 292

HopefulFutureMedic

Original post by George_

I have Chem. Salters B as well, which is tough. When did you properly start revising OTHER than at school? I suppose I started a week & a bit ago :/

Sure I'll do OK though.

Oh, i do AS chemistry Salters, and i hate it! OCR A is so much better.
There isnt any faffing about with storylines, and the chapters that you need
to know are in order! :smile:

Whereas i find myself spending half an hour, sorting out the chapters
in the Chemical Ideas book that i need to learn. Rather than actually learning
it. I'm dreading f332...how about you?

Reply 293

4MANU4EVER4

Can someone please explain to me the difference between carrier proteins and channel proteins?
Thanks in advance :smile:

Reply 294

shybrowngirl

hi can anyone give me brief points from the mark scheme to remember these:

The use of monoclonal antibodies in enabling the targeting of specific substances
and cells.

The gross structure of the human heart and its associated blood vessels in relation to function.

Pressure and volume changes and associated valve movements during the cardiac cycle.

The effects of fibrosis, asthma and emphysema on lung function.

The gross structure of the human gas exchange system limited to the alveoli,
bronchioles, bronchi, trachea and lungs.

The essential features of the alveolar epithelium as a surface over which gas
exchange takes place.

The exchange of gases in the lungs.

The mechanism of breathing.

the applications and implications of science in developing improved oral
rehydration solutions

ethical issues associated with trialling improved oral rehydration solutions on
humans.

The role of carrier proteins and the transfer of energy in the transport of substances against a concentration gradient.

The role of carrier proteins and protein channels in facilitated diffusion.

using the fluid-mosaic model to explain appropriate properties of plasma membranes - I HAVE A FEELING THIS CAN BE THE 5 MARKER!!!!

The arrangement of phospholipids, proteins and carbohydrates in the fluid-mosaic model of membrane structure.

The role of the microvilli in increasing the surface area of cell-surface membranes.

using the lock and key model to explain the properties of enzymes.

The properties of enzymes relating to their tertiary structure.

Description and explanation of the effects of temperature, competitive and non-competitive inhibitors, pH and substrate concentration - ONE OF THESE CAN COME UP AS A 5 MARKER!!

The gross structure of the human digestive system limited to oesophagus, stomach, small and large intestines, and rectum. The glands associated with this system limited to the salivary glands and the pancreas - CAN THESE COME UP AS A 5 MARKER?

I know it's a lot!!!! but please please, i'm sure these will benefit you guys as well :biggrin:

and thanks to britash and Chloe0493 to help me with my previous questions!! :biggrin:

good luck everyone for tomorrow! x

(edited 11 years ago)

Reply 295

Rizzy J

Original post by britash

8 I think.
Plus all my schools' booklets. Fun day :/

does your school booklets have past paper qs or are they qs they made themselves?

Reply 296

. . .

Original post by 4MANU4EVER4

Can someone please explain to me the difference between carrier proteins and channel proteins?
Thanks in advance :smile:

Channel proteins are used for ions and only used in facilitated diffusion whilst carrier proteins are for large molecules and can be used for facilitated diffusion or active transport or co-transport).

Reply 297

iTwIsTeDmInDx

Can somebody help with the following questions:

3 marks: Describe the process of facillitated diffusion? (what are the marking points?)
5 marks: Describe the process of Active Transport? (what are marking points?)
5 marks: Describe how cholera affects the chloride exchange (again what are the marking points?)

These are all hypothetical but they're the areas I struggle with, any help is much appreciated

thanks.

Reply 298

Jack_Smith

does anyone have the link to the biology answers for the exam style question in the AQA Nelson Thornes book.

Reply 299

iAkash

Hey guys, was wondering if the Co-transport of Na and glucose is an example of active transport, or just facilitated diffusion? So does it move against the concentration gradient or..? And if not what should we talk about if a question comes up asking to describe the cotransport?