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OCR Biology F211 Exam - Tues 11'th January 2011

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Reply 360
Original post by Konshi
Couple of pages back a guy posted a pretty good explanation. Here's mine that I've just written up based off of him and textbook:

Blood enters the tissue through the arteries, with a high hydrostatic pressure as it has just been pumped by the contraction of the heart (ventricular systole). These arteries branch off into a network of arterioles and capillaries, which will eventually link up with venules to carry the blood back to the heart.
The high hydrostatic pressure forces fluid out of the capillaries through tiny pores in the capillary wall. There is a net loss of fluid from the upstream end of the capillary near the arteriole. The fluid that leaves is called TISSUE FLUID.

Blood Erythrocytes, leucocytes, platelets. Hormones and plasma proteins. Some lipoproteins.
Tissue Fluid Some phagocytic white blood cells. Some hormones. No fats.

Plasma proteins are not able to cross through the pores in the capillary wall. Neither are erythrocytes, platelets, leucocytes. Therefore the tissue fluid has a higher water potential. The tissue fluid transports substances such as oxygen to the tissue cells. It now has a lower hydrostatic pressure, and has a higher water potential due to lacking the bigger solutes, so the fluid returns to the blood via osmosis down a water potential gradient.

Lymphatic system returns lost fluid and proteins to the blood. Fluid enters by diffusing into tiny lymph capillaries, where the fluid is called LYMPH. Composition is near similar to tissue fluid, except lymph has a higher concentration of lymphocytes, produced by the lymph nodes. Lymphatic system drains into the bloodstream near the junction of the venae cavae and the right atrium.

Hope that helps mate. Not sure whether I should go for the all nighter. Never done an exam with 0 hrs sleep lol.





Cheers, I did see the other one but i didnt really understand it, your explanation was better lol get most of it now

thanks again:biggrin:
fml ima fail so bad tomorrow :frown:
Reply 362
Original post by michelleabelle
fml ima fail so bad tomorrow :frown:




hahah join the crew lol:biggrin:
Reply 363
3rd time lucky i hope, third time ive taken this damned paper. Good luck to all :biggrin:
Good luck tomorrow everyone. See you on the other side (this is a resit for me)
i had my tonsils out over christmas and coud hardly do any revision! ive read loads off this thread and hopefully will remember it :/ im getting up at like 5 to do a bit more :/ good luck! and good night :frown: xx
Reply 366
Original post by taunt
hahah join the crew lol:biggrin:


Optimism, there's still potentially ~8 hours of revision in which we can learn the entire syllabus from scratch
Reply 367
Original post by Zeddude
3rd time lucky i hope, third time ive taken this damned paper. Good luck to all :biggrin:




lol i hope you dont mind me asking,:tongue:
but what did you get for the ones you already done?
Reply 368
Original post by Konshi
Optimism, there's still potentially ~8 hours of revision in which we can learn the entire syllabus from scratch


well u just explained the hardest topic in F211, so ur oright and chillin' lol :tongue:

me?....well im siting on my bed thinking aaaaaaaaaaaaaah :eek: another minute closer to the exam!!!

yep happy days lol:biggrin:
Reply 369
best of luck everyone!!!
Reply 370
Original post by taunt
lol i hope you dont mind me asking,:tongue:
but what did you get for the ones you already done?


Of course i dont mind you asking :tongue:

in Jan 2010 i got a D no idea how 52/90 UMS
in June 2010 i got a C LOOOOL 2 marks more, 54/UMS.

How annoying, but i got an A in F212 in june, so i dont know why i cant grasp this stuff, i find chapter 5 really hard, and recently, lots of heart/tissue fluid/haemoglobin curves have been popping up..
Reply 371
well lets hope you dont have to do another resit (thats if theyll allow u) but bloody hell WOW you got an A for F212 thats really good, il probably have to do like 10 resits for that one, so atleast you got that grasped lol
Reply 372
hus doing all nighters??????
Reply 373
Yeah haha, i hope i dont do any resits in June, final big A2s, need to focus on them!

F212 is disgustingly aweful haha. i literally got the UMS needed for an A. 120/150 exactly

Best of Luck with everything, especially tomorow :wink:
can someone give me correct definition for diffusion and osmosis
i know this stuff is easy but we can loose marks as it is very specific
8 hours left till exam people
going to sleepp in abit hope for the best hopefully 3rd time lucky
Original post by stargirll
ooooh could i have a copy too? Im so stressed for this bio exam and they would really help :biggrin:


Can I have it too please? :h:
go to sleep bro lol wat time u call this
Reply 377
Original post by undertaker1
can someone give me correct definition for diffusion and osmosis
i know this stuff is easy but we can loose marks as it is very specific
8 hours left till exam people
going to sleepp in abit hope for the best hopefully 3rd time lucky


diffuson is the movement of molecules from a region of high concentration to a region of low concentration down a concentration gradient. it is a passive process and relies simply on the kinetic energy of the molecules

osmosis is the movement of water from a region of high water potential to a region of low water potential down a water potential gradient across a partially permeable membrane
anyone reckon eukryotic and prokaryotic mite come up because im confused
text book says prokaryotic cells have no flagella/undipolia however exam questions say sometimes present so what is it
thanks man but isnt it the net movement

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