AQA Biology Unit 1 January A-S 2012 *EXAM FINISHED*

I will do dont worry I think i did in the chem thread, if i remember correctly
Aww its alright anyway, thanks for the thought though



Hopefully! I'm sure we'll be crazy spamming this thread after the exam like "WHAT DID YOU PUT FOR THIS?!?".. etc.

Will you be on here straight after the exam? Its a morning exam - and we have to go back to lessons.. but I never do as im so anxious hahaaha

Have you finished all your revision? You seem uber confident dude!

A few questions. [Just made these out of the blue, will do them myself too to recap] )

I dont think so.. I've got chemistry and then maths (lessons, and considering ive got those 2 exams both on the friday i should probably go haha)afterwards, but will be home at about 2 or so to make myself even more anxious talking about it with you lot

1)higher blood pressure means that there is a higher risk of thrombosis, in which the coronary arteries are blocked reducing the supply of oxygen and glucose to the heart muscle affected. This means the muscle cells cant respire causing the heart muscle to die.
2)Blood enters the vena cava and pulmonary veins. As the pressure in the atria rises, the atrioventricular valves are forced open. Both the atria and the ventricles are relaxed as the blood fills the ventricles.
3)Alveoli have a large surface area to volume ratio to speed up the rate of gas exchange. The alveoli are one cell thick to allow a short diffusion pathway so that rapid diffusion is maintained. Air with high oxygen concentration is breathed in and air with low oxygen concentration is breathed out, this maintains a steep diffusion gradient. thats all i can think of
4)External intercostal muscles contract while internal intercoastal muscles relax. The ribs are pulled upwards and outwards, diaphram contracts causing it to flatten increasing the volume of the thorax. Atmospheric pressure is greater than pulmonary pressure so air is forced out of the lungs
5)Euokaryotic cells:
Linear DNA
80S ribosomes
Membrane bounded organelles are present
Nucleus is present
Prokaryotic cells:
Circular DNA
70S ribosomes
No membrane bounded organelles are present
No true nucleus is present
5)The heart muscle is myogenic, the contractions are stimulated within the heart. The SAN sends a wave of electrical activity to both atrias making them contract. Non conductive tissue stops the electrical impulses reaching the ventricles. There is a short delay to allow the atrias to empty before the ventricles contract. The AVN sends an electrical activty to the bundle of His where the fibres branch off in the base of the ventricles. The ventricles contract at the apex of the heart.
6)Salivary amylase is produced in the mouth which hydrolyses starch into maltose. The food passes to the stomach where the salivary amylase is denatured to prevent further breakdown of starch. The pancreas produces pancratic juice which contains pancreatic amylase which hydrolyses any left over starch into maltose. The lining of the small intestine produce maltase which hydrolyses maltose into alpha glucose
7)??
8)the water potential in the cell is lower than the water potential outside the cell so water moves out of the cell and into the concentration by osmosis causing it to burst
9)???

I will do dont worry I think i did in the chem thread, if i remember correctly
Aww its alright anyway, thanks for the thought though

I've been in College today and done a revision session for Biology which had my teacher throwing random questions at me that popped into her head for about 2hrs, and I coped very well. This has given me some confidence, for sure.

I've got another session tomorrow for Biology with my other teacher (as I have two teachers) and so that will pretty much complete my revision as I've already done what I had set out for myself.

Although, I'll casually keep with it so I'm ticking over nicely for the exam. We've got a VLE with plenty of resources on it, and so even though a lot of it is repetition, it's repetition of a slightly different form.

You should watch some of his programmes if you havent already. There was one on recently called "A night with the stars" (or something), which had some chemistry stuff on it too that was kinda relating to what we're doing in chem1 (only a little bit like structure of diamond and stuff like that but still! )

Random neg is random. Thanks brah!

Yes he did. I didn't even know who he was until this year because all the 'physics-y' people from my form just talk about physics and him, and my form tutor etc.
He got a D on physics... and hes now famous from it haha XD
Your old physics teacher must have gone to my school/sixth form then :P x

Same as this.

In fact, I don't even think I'll look at a thread regarding the Biology exam until after I've done the Math & Chemistry exams on Friday. I'll be tempted, but it's better for me to focus on the others as I won't be able to do anything about the Biology and what will be will.

Although, I'll slap an unofficial mark scheme out Friday evening if no-one else has already done so by then. Then you can all shoot me down in flames.

You mixed the numbers up so this might get confusing hahah. But your 9 (question 10) is to do with ORS. Your 7 (Q 8) i'd guess would just be low to high conc through carrier proteins? Not sure how else to expand

I'm really not confident at all.
I think I know my stuff.. but then I struggle to apply things to certain areas (confusing to explain I know)...

When do you know the difference between co-transport, facilitated diffusion, active transport etc.?
Can some please give example or something?
I've done a question about absorption of glucose to epithelial cells, but which ones transport the glucose..? Is it active transport with ATP and sodium-potassium pump adds in potassium to cell and removes sodium from cell (to blood). Does that then create a concentration gradient, so sodium and glucose more through a.. carrier protein... maybe?? into the epithelial cell... ???

*thanks by the way to whoever helps *

Co-transport: I think the only way this applies is to the glucose+Na in absorbtion of glucose. (that we have ot know)
Facilitated diffusion: High to low concentration through carrier or channel proteins.
Active transport: Low to high concentration through carrier proteins only.

Absorbtion of glucose (this is a condensed version as my brain is slowly shutting down with it being 12am haha)

-Na removed from epithelial into blood via active transport through Na-K pump.
- Na then moves from high to low conc with a glucose molecule from the lumen of intestine to epithelial cell via cotransport through a carrier or channel protein.
- Glucose is then at a higher conc in epithelial cell than in blood, so moves via facilitated diffusion through carrier/channel into the blood.

Woah its super windy Doubt I'm going to be able to sleep tonight ^^ x