AQA AS Unit 1 Biology Exam 21st May 2015

I hope everyone does well in their future exams. Good Luck!
May someone help me in this AQA January 2012 question 5b ii) (2ndpart)- i did cardiac output =heart rate * stroke volume, which is 85.7*98=8398.6 but the markscheme states 7905-7998. How?
Secondly, I am currently stuck on january 2011 qs 4ciii) and 5b)?
And I need help on understanding the process of co-transport and sodium potassium pump, and also what is the difference?
Thanks alot, more questions on the way...

Reply 382

How does a Golgi Apparatus form lysosomes and how do they work? The book is confusing me, are they inside the vesicle?

Can someone simplify it please, would be much appreciated :h:

Reply 383

Original post by Ozy96

How does a Golgi Apparatus form lysosomes and how do they work? The book is confusing me, are they inside the vesicle?

Can someone simplify it please, would be much appreciated :h:

- Golgi apparatus modifies+packages+transport proteins, forms lysosomes, They are transported by vesicles - you just need to the basic functions of these organelles, dont go into the much depth. Hope that helps

Reply 384

Original post by RespectedDon

I hope everyone does well in their future exams. Good Luck!
May someone help me in this AQA January 2012 question 5b ii) (2ndpart)- i did cardiac output =heart rate * stroke volume, which is 85.7*98=8398.6 but the markscheme states 7905-7998. How?
Secondly, I am currently stuck on january 2011 qs 4ciii) and 5b)?
And I need help on understanding the process of co-transport and sodium potassium pump, and also what is the difference?
Thanks alot, more questions on the way...

Working out cadiac output question:

Look at 0.1 sec you'll see that the highest volume of blood in the ventricle.
Now 0.5 sec you'll see lowest volume of blood in the ventricle
Stroke volume is the volume of blood pumped out at each beat.
So you subtract the value of 0.1 (148 cm^3) by 0.5 (55cm^3) giving you 93cm^3 of blood pumped out.

Now just times it by the heart rate you got and you should get the answer

Hope that helps

Reply 385

Do we need to know the functions and structures inside the nucleus? or just the general function of the nucleus

Reply 386

shhh123

Can anyone explain how to tackle data questions ? :O

Reply 387

Helpme.

8

Original post by shhh123

Can anyone explain how to tackle data questions ? :O

you just don't answer them

Reply 388

Amplifier786

13

Can someone please explain the sodium potassium pump , its confusing 😫

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Reply 389

Original post by Ozy96

Working out cadiac output question:

Oh wow, now i get it, cheers mate and yeah-you just need to the main function of a nucleus.

(edited 8 years ago)

Reply 390

Original post by mrnazz00923

Can someone please explain the sodium potassium pump , its confusing 😫

Posted from TSR Mobile

Check this video, explains the whole process of absorption in the small intestine

https://www.youtube.com/watch?v=8Fp91-ostBE

Reply 391

Original post by RespectedDon

Oh wow, now i get it, cheers mate and yeah-you just need to the main function of a nucleus.

Ahh I see, thanks! and no worries, glad to help :h:

Reply 392

Amplifier786

13

Original post by Ozy96

Check this video, explains the whole process of absorption in the small intestine

https://www.youtube.com/watch?v=8Fp91-ostBE

Thanks :-)

Posted from TSR Mobile

Reply 393

Original post by Ozy96

Ahh I see, thanks! and no worries, glad to help :h:

Your welcome- thanks for your time- how do you do question 3b) from Jan 2010 paper and likewise I generally don't understand the comparison of inhibitors on the rate of reaction graph and how to draw it (page 36 on AQA book). Thanks.

Reply 394

Malicious

2

Resitting this exam in a couple days too ! Done like 8 past papers over the past 2 weeks got C's and B's and 1 A. I'm not confident at all though. I'm just gunna do past papers all day tomorrow so the technique is fresh in my head and do my best. Hoping for a C or B. Does anyone have any predictions?

Reply 395

Original post by RespectedDon

Your welcome- thanks for your time- how do you do question 3b) from Jan 2010 paper and likewise I generally don't understand the comparison of inhibitors on the rate of reaction graph and how to draw it (page 36 on AQA book). Thanks.

Well the effect of a competitive inhibitor is overcome by increasing substrate concentration
So the curve will be lower because of the inhibitor not allowing E-S complexes to be formed so the ROR will be lower. However, it gradually increases with an increase in substrate concentration.

This is because having a higher concentration of substrates gives us a higher chance of forming E-S complex.
And levels off at the same concentration due to the active sites being already occupies.

I hope that made sense, let me know if you need more clarification

Reply 396

kkboyk

21

I shall start revision for it tomorrow after Maths exam, though I done a bit over the weekend I still need to cover the data questions -.-

Reply 397

Original post by Ozy96

Well the effect of a competitive inhibitor is overcome by increasing substrate concentration...

Best explanation that I have read. you have clarified the markschemes' answer -"Curve is lower and plateaus at a higher substrateconcentration". Thank you. And yhh- can you do the same with non-competitive inhibitor cheers

(edited 8 years ago)

Reply 398