AS Biology f212 26th May 2011

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Reply 180

fevziye

Original post by slacker07906

I know that. That's the taxa aint it? Mine is did king phillip come over for great s** :tongue:

Yeap they are the taxa! What questions do you think will come up?

Reply 181

peaches1

Biodiversity and graphs...

what graphs?

Reply 182

Bi0logical

Brief info on smoking;

Short-term effects;
Tar is a combination of chemicals that lines the airways and alveoli. This increases the diffusion distance for O2 to enter blood and for CO2 to leave. Tar also paralyses cilia on the surface of the airways so they cannot move mucus to the back of the mouth. Tar also stimulates the globlet cells and mucus-secreting glands, so more mucus is produced.
Bacteria and viruses that are trapped in the mucus are not removed. They can multiply in the mucus and block the bronchioles. Presence of Bacteria/Viruses means the lungs are more susceptible to infections. Smokers more likely to catch influenza and pneumonia

Long-term effects;
The mucus and bacteria irritates the airway and they need to be cleared to get oxygen in the alveoli. This leads to smokers cough to try and shift the bacteria mucus. Constant coughing damages the lining of the alveoli and airways. This lining is then replaced by scar tissue, which is thicker and less flexible. The layer of smooth muscle in bronchioles thickens. Reduces the lumen of the airway, which restricts air flow.
Frequent infections of bacteria/virus can inflame the lining of the airways which damages it. This attracts white blood cells, which release an enzyme called elastase, it digests parts of lining of the lungs, also damages the elastic tissue. Loss of elastic tissue in the alveoli can reduce elasticity of their wall making it more difficult to expell/breath out. This can cause Alveoli to burst due to pressure in the lungs (Emphysema)

Chronic Bronchitis:
Chronic means long-term, this is where there is inflammation to the lining of airways, damage to the cilia and overproduction of mucus.
Symptoms;
- irritation in the lungs
- continuous coughing
- coughing up mucus w/ bacteria and white blood cells.. ew

Emphysema;
Talked about this earlier in the long-term effects.
The loss of elasticity in the Alveoli, which can cause them to burst.
Symptoms;
- Shortness of breath, especially when exerting.
- The loss of elasticity makes it more difficult to exhale
- Breathing becomes shallower and more rapid
- The blood is less well-oxygenated so one can become fatigue.

Lung cancer;
Cigarette smoke contains carcinogens, these are chemicals which can cause cancer.
They enter the cells of the lung tissue, then enter the nucleus. They have direct effect on genetic material. Any changes to the genetic material is called a mutation.
symptoms;
- Continual coughing
- Shortness of breath
- Pain in the chest
- Blood coughed up

COPD (chronic obstructive pulmonary disease)
it is a combination of diseases that include emphysema, chronic bronchitis and asthma.. hmm not very nice

Long-term effects;
The mucus and bacteria irritates

Reply 183

Niki_girl

Original post by Bi0logical

Brief info on smoking;

Unfortunately I can't +rep you again until I "rate some other members" but if I could I would, thanks :smile:

By the way, how do you think F211 went? Just trying to guage some general consensus, as I think I really messed up :s-smilie:

and a lot of stuff I revised didn't come up - so I'm hoping most people found it quite a hard paper :biggrin:

Thanks again,

Reply 184

Bi0logical

Original post by Niki_girl

Unfortunately I can't +rep you again until I "rate some other members" but if I could I would, thanks :smile:

By the way, how do you think F211 went? Just trying to guage some general consensus, as I think I really messed up :s-smilie:

and a lot of stuff I revised didn't come up - so I'm hoping most people found it quite a hard paper :biggrin:

Thanks again,

It's ok.. which F211 exam? the re-sit or the January one

Reply 185

Rup

Original post by eatpraylove

'Kool' = Kingdom
People = Phylum
Can = Class
Obviously = Order
Fart = Family
Gas = Genus
Silently = Species

Boy in my class made it up but it's the one I remembered the quickest xD

I remembered it as DicK PiC OF GS! looool

Reply 186

slacker07906

Wow all this info makes me stressed -_-

Reply 187

JChoudhry

+ Reps are from me by the way :smile:

I did a past paper, got 79/100 but a 0/8 on a question on B Lymphs :colondollar:

Reply 188

slacker07906

Original post by JChoudhry

+ Reps are from me by the way :smile:

I did a past paper, got 79/100 but a 0/8 on a question on B Lymphs :colondollar:

Oh that paper. That's amazing! I got 68 :frown:

but to be fair I didn't do the last 3 or 4 pages because I didn't see them lol. You not revised B lymphocytes?

Reply 189

JChoudhry

Original post by slacker07906

Oh that paper. That's amazing! I got 68 :frown:

but to be fair I didn't do the last 3 or 4 pages because I didn't see them lol. You not revised B lymphocytes?

I have now :p:

I didn't want to do the question because I hadn't covered it in my revision yet, otherwise I would've written down clonal selection and clonal expansion to get 2 marks. lol :laugh:

Reply 190

Bi0logical

Original post by JChoudhry

I have now :p:

I didn't want to do the question because I hadn't covered it in my revision yet, otherwise I would've written down clonal selection and clonal expansion to get 2 marks. lol :laugh:

Which past paper is this? :tongue:

I want to try it

Reply 191

JChoudhry

Original post by Bi0logical

Which past paper is this? :tongue:

I want to try it

June 2009

(I think) It's the very first paper though. After the specimen.

Reply 192

Citrus_lime

Anyone else have C2 Maths the same day, in the morning? It's so annoying! I have only revised 1/4 of biology so far, and I have 2 more exams before Biology. What do we think is going to come up? I hate the way all the questions are getting harder, sometimes I don't even understand what they want you to say!

2 days... :s-smilie:

Reply 193

Niki_girl

Original post by Bi0logical

It's ok.. which F211 exam? the re-sit or the January one

The one on the 16th of May this year, F211 - I didn't sit the January one - but I think I might have to resit that one! :frown:

ah well, perhaps F212 on thursday will magically become a really easy paper, full of fill-in-the-gap and match-up questions which are each worth 10 marks :colondollar:

Reply 194

Niki_girl

Original post by Citrus_lime

I have 2 exams before Biolgoy Unit 2. One is tomorrow morning, the other is the morning of F212 :eek:

I have SO MUCH F212 revision to do and I hate that paper in general :bawling:

Reply 195

slacker07906

Hi. I've just been looking through my paper from january 2011 and I am quite concerned.

On Q.3(b)(iii)- The question was "explain the importance of species evennes in determining the biodiversity in a habitat?

Mark scheme answer-
(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 ;
example used to illustrate explanation of mp 3 or 4 ;

My answer

"Species evenness is the measure of abundance of each species, in comparison to one another (surely this is markng point 1?). If species have unequal populations, then this indicates a diverse habitat in which quite a lot of species dominate. (another mark?) If speies have unequal populations in each species, this indicates an unstable habitat with only a few species dominating (another mark surely?), hence likely to be effected by disease etc..."

However not even one mark. They said I contradicted myself, have no idea where.

Also on structure of haemoglobin question.

Mark Sheme Answer

sequence / chain, of amino acids ;
(amino acids) joined by peptide bonds ;
secondary
alpha / ?, helix ;
small regions of, beta / ?, pleated sheet / fold ;
hydrogen / H, bonds ;
tertiary
secondary structure / helix / polypeptide chain, undergoes further, coiling / folding ;
3 bonds / interactions from: disulfide / ionic / hydrogen / hydrophobic or hydrophilic ;
hydrophilic R groups on outside (of molecule) / hydrophobic R groups on inside (of molecule) ;
quaternary
4, polypeptides / subunits ;
2, alpha / ?, chains and 2, beta / ?, chains ;
1 haem (group) per polypeptide / 4 haems (per molecule) ;
prosthetic group (is) haem, (which) contains Fe2+

Now in my answer I got 4/7 marks. However I should have got more. I clearly stated "Each chain consists of an haem group. Each haem group consists of an Fe2+ ion which gives blood its colour" So thats another 2 marks is it not?

If this is OCR being picky, then this is ridiculous. Our education system has got to a point where they try and distinguish candidates with every little chance they get, when they clearly know what they are talking about. They need to bring back the old system because this is ridiculous.

Don't get me wrong, I know I can't do anything about it now, but I was just letting everyone know that make sure you don't make silly little mistakes like me. I was 2 marks away from an A and made such stupid mistakes throughout the paper.

(sorry about spelling mistakes)

(edited 12 years ago)

Reply 196

catscatscats22

Just wondering, for the section on Nucleic Acid etc, do we need to know about anticodons etc.?
Because its not on the specification, but I found it in my notes.
So confused D:

Reply 197

slacker07906

Original post by catscatscats22

Just wondering, for the section on Nucleic Acid etc, do we need to know about anticodons etc.?
Because its not on the specification, but I found it in my notes.
So confused D:

No thats A2 but it would be helpful if you knew that anti-codons are situated on tRNA molecules and bind to the complementary codon on the mRNA, in order to bring in the correct amino acid. But you don't even need to know that.