Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD !

I didn't answer this because I wasn't too sure
However, I think breathing rate can be determined by the number of peaks in the spirometer trace. So a trough and a peak is 1 breath.
Tidal volume is the difference in volume of gas breathed in between each peak

Haven't revised that fully but that's what I can think off

Not sure why MS says that....biology mark schemes are so vague

lol okay
so basically if you count the number of peaks within a minute, it should be possible to work out the breathing rate, right?

Could you please help me on post #117

Can someone help me with LO 17 in topic 7: "Explain how genes can be turned on and off by DNA transcription factors including hormones"

Cheers.

For that point I know about peptide hormones like human growth hormone, insulin and EPO and steroid hormones like testosterone. With peptide hormones, they directly bind to a complementary receptor on the cell surface membrane which then causes a 2nd messenger to bind to a receptor in the cytoplasm to cause the transcription factors to be active while with testosterone, it directly binds to the receptor to bring about transcription. Transcription can only happen when the transcription factors and the RNA polymerase bind together and then bind to the promoter region, repressor molecules may prevent this by binding to the promoter region or transcription factors. Activator molecules have the opposite effect.

Could anyone quote me if what I said is completely wrong or if I've left stuff out?

Right i see so is this whole concept related to the "Gene expression" section in the scientific article?

Yes, pretty much.
If they have a graph, which is split up in rest, training and recovery, and they want you to find the breathing rate for rest.
My teacher says count the number of peaks in the rest section of the graph
Gotta pop off now to revise the article pfffft

ahh thanks just one more q, do you have the jan 2012 paper with MS? I can't seem to find it anywhere! )

can u plz copy and paste post # 117 so i can read it to help u

I am soooooooooooooooo behind. I'm going to only have like a day to revise all this + article.

I need a 126/180 UMS to get an A (including coursework) I hope we all get our grades!

Article predictions? I have loads:

Pages 1 – 3

1. Describe using specific examples that there is a correlation between the media and amount of body dissatisfaction.


2. Analyse and interpret the possible link between obesity and health issues, such as diabetes, CVD and cancer.


3. Lipids are biological molecules that are insoluble in water, but soluble in organic solvents, like ethanol. Triglycerides are lipids made out of three fatty acids and one molecule of glycerol joined via an ester bond. The glycerol molecules are all the same. Recall the variation between the fatty acids.


4. When a triglyceride is broken apart by hydrolysis, how many components are found as products? Name them.


5. Suggest reasons why it is likely that gender plays a role in susceptibility to eating disorders.


6. List key features of a good study used to determine health risk factors. Refer to examples in the text.


7. Analyse and interpret data about the threats of eating disorders.


8. Recall how brain activation patterns are used to determine the influence of exposure to media images to ones sense of self.


9. The energy you need in a day depends on your Basal Metabolic Rate (BMR) and level of activity. BMR varies with gender, age and body mass. Discuss this statement.






Page 4

1. How can restricting calories to 1200 calories per day affect cortisol and its subsequent effects on the body (para 18)?


2. In paragraph 20, the brains of rats have been studied to see the effect of ‘yo-yo dieting’. Why are rats considered a good model for study and describe the ethical issues involved in the use of animals in a trial of this kind?


3. Describe the waist-hip ratio and one other measure of physique or obesity.


Page 5

1. The electron transfer chain leads to ATP synthesis. How is this explained by the chemiosmotic theory?


2. Suggest how UCP-1 may disrupt respiration at the Electron Transfer level and prevent the production of some ATP.


3. Explain how transcription factors work.


4. Outline the process by which peptide hormones can affect gene transcription.


5. Explain how BAT is able to regulate both core body temperature and body weight.


6. Explain how PET scans work.


7. Suggest why heart and brain need to absorb large amounts of glucose.


Page 6

1. How does BAT deposition differ in rodents and humans (para 34)?
In adult humans, BAT is mainly deposited above the collar bones and around the neck, however in rodents BAT is mainly deposited between shoulder blades.


2. Why have thyroid hormones and other drugs that stimulate the SNS (Sympathetic Nervous System) been used then abandoned?
Unpleasant side effects were encountered; therefore the thyroid hormones and drugs were abandoned.


3. Describe the effects of fucoxanthin from seaweed (paragraph 38).
Increase the production of UCP-1 in White Adipose Tissues.


4. Explain why studies of fucoxanthin involving humans might be necessary?
Other animals are dissimilar to humans, therefore it is necessary to test fucoxanthin on humans to observe its effectiveness and any possible side effects.


5. Describe the clinical trial process/modern drug testing process that would be needed if fucoxanthin were to be licensed for human trials.
The first stage of drug trials would be on a large number of healthy volunteers to test for any unpleasant side effects that may have been missed in previous trials. The second trial would be on a large number of patients to test the effectiveness of fucoxanthin in treatment of obesity.


6. Use your scientific knowledge to describe the process by which mice could be genetically engineered to produce high levels of PRDM16 proteins (para 40).



Page 7

1. Paragraph 41 suggests the use of gene therapy. Explain how they could ‘transform stem cells’ with the PRDM16 gene.

2. ‘Tenmodulin’ (paragraph 44) is a transmembrane glycoprotein. Explain the post-transcriptional modifications that are made that enable the glycoprotein to reach its final destination.
The protein is


3. Pararaph 45 states that mRNA codes for various proteins. Explain how mRNA templates are used to specify the chemical structure of a protein.
tRNA molecules


4. Paragraph 46 mentions the ‘dopaminergic system’. Name and describe a disease where dopamine secretion is affected and describe the main symptoms.


5. Paragraph 45 mentions the protein ‘interleukin-6’, which is an anti-inflammatory protein. Suggest the impact of anorexia on the immune system.


6. Epigenetic changes’ are where the DNA base sequence remains the same, but changes are made to other parts of the DNA structure. This may affect gene expression. Using your knowledge of DNA structure and protein synthesis, suggest how ‘DNA methylation’ may ‘alter gene expression’ (paragraph 46).

Sorry for the odd format, hope that helps people who are stuck on the article, if you have more, let me know! x

hey bright
h was ur jan bio exams?

Hiya :] I got one mark off an A, 94.. :'( I was so upset but this time if I get the same I'd be over the moon (provided that I get an A overall)

How about you?

omg only one mark that is annoying but hopfully u will do it this time im sure that the grade boundries this session will be low...
so u r aiming for A* that is great ;D

well i got an overall B grade so it is quite bad and im re-doing all the A2 exams that is depressing

A B isn't bad! :] I can't get an A* because I only got 94/120 for unit 4. + I haven't done any revision for this yet because I retook 2 massive chem units that I revised for, so now I'm behind. I have another chem exam on the 19th and an Eng Lit on the 20th and dreading all of them!

And and my A2 bio c/w was crap.

It was only on the last page.

QP: http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/January%202011%20-%20QP/6BI05_01_que_20110127.pdf

Q5ci- I don't understand the question or the mark scheme. Can someone please explain it to me.
It's jan 11

MS: http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/January%202011%20-%20MS/6BI05_01_rms_20110309.pdf