OCR Biology F211 Exam - Tues 11'th January 2011

hahhaha, i am never ready!! I'm retaking it, if i get an E again, i may just have a mental crisis. Are you ready?

I don't think you can ever be ready for a test but this one I am seriously not ready for!
Just had a panic attack feeling I don't know anything!
I blame my maths exam - I was concentrating on that :frown:

but yh, hope i do well. Good luck! and judging from your posts, I really don't think you'll get an E - you'll do a lot better

Reply 161

livingforthefuture

Original post by giraffegiraffe

- measure size of image given (mm)
- multiply by 1000 (convert to micrometers)
- divide by the magnification (given or work it out- see below)
= actual size (in micrometers)

If you don't know the magnification and can't work it out from
magnification = size of image over actual size,

then work out magnification from the scale line:

magnification = length of scale line given divided by length of scale line measured (mm)

hope that helped :smile:

thanks it really did

Reply 162

Tabers

15

Original post by hellosarah

hahhaha, i am never ready!! I'm retaking it, if i get an E again, i may just have a mental crisis. Are you ready?

At least your situation is slightly better than mine. If I get a U again then I will have a massive mental crisis and hell knows what will happen. I STILL haven't worked out how I did so bad, I did loads of revision for it the first time and loads for this retake.
Good luck anyway!

Reply 163

giraffegiraffe

10

livingforthefuture- glad to hear it :smile:

hope i remember it for tomorrow

Original post by pastpaper-guy

possible how science works questions?

potometer setting up/precautions seems to come up a lot, no air bubbles, dry leaves, airtight seal etc!
do we have to know any other practical stuff?
oh- spirometer precautions- disinfect the mouthpiece and use soda lime to absorb CO2
anything else?

(edited 13 years ago)

Reply 164

pastpaper-guy

7

Original post by giraffegiraffe

livingforthefuture- glad to hear it :smile:

hope i remember it for tomorrow

potometer setting up/precautions seems to come up a lot, no air bubbles, dry leaves, airtight seal etc!
do we have to know any other practical stuff?
oh- spirometer precautions- disinfect the mouthpiece and use soda lime to absorb CO2
anything else?

im just worried they will try to incorporate some of the syllabus into a real example. E.g they give you a question about the heart and talk about a kid who has a condition where the right atria has a hole in it.
Explain why the kid feels tired alot of the time?

not exactly like that but u get the point

Reply 165

The Smeezington

9

Can anyone willing to help follow this link:
http://www.thestudentroom.co.uk/showthread.php?p=29294540&highlight=phloem.

Reply 166

giraffegiraffe

10

Original post by pastpaper-guy

im just worried they will try to incorporate some of the syllabus into a real example. E.g they give you a question about the heart and talk about a kid who has a condition where the right atria has a hole in it.
Explain why the kid feels tired alot of the time?

not exactly like that but u get the point

ohhh yeah i see what you mean but gosh i hope not .. the not-straightforward questions are the worst! its so hard to try to realise what they want you to say. the pastpaper questions i've tried so far have been kindof straightforward in the way they're asked but its just getting those exact words in which is a killer!
is everyone using the black and purple ocr textbook?

Reply 167

Princess Kawaii

15

Original post by hellosarah

1- Membrane bound receptors have a specific recognition site which has a complementary shape to this specific hormone or drug. Any cell with a receptor is called a target tissue.
So the hormone/drug binds to the receptor on a target cell surface membrane, causing the target cell to respond in a particular way.
Some medicinal drugs block receptors.

2 + 3- Epithelial cells:
Squamous epithelial tissue:
- Thin, smooth, flat surface.
- Provides a short diffusion pathway. E.g: in alveoli; for the exchange of oxygen and carbon dioxide.
Cilliated epithelial tissue:
- Made up of column-shaped cells; cillia.
- Cillia wave in a synchronised rhythm to move mucus.
E.g: in the breathing tract & moving egg cells along the oviduct.

4 - A developing fetus obtains oxygen from its mother's blood and its own lungs.
Oxygen arrives at the placenta in combination with haemoglobin.
The partial pressure of oxygen in the blood vessels in the placenta is relatively low, as the fetus is respiring. Therefore, the mother's haemoglobin releases some oxygen, diffusing from the blood into the fetus's blood across the placenta.
Partial pressure of oxygen in the fetus's blood is only a little lower than that in its mother's blood, meaning diffusion would occur at a very slow rate.
BUTT this doesn't happen as fetal haemogblobin combines more readily with oxygen than adult haemoglobin.
Fetal haemoglobin is said to have a HIGHER AFFINITY for oxygen than adult haemoglobin. So at any partial pressure of oxygen, fetal haemoglobin will take oxygen from adult haemoglobin.

Does any of that even make sense? :confused:

heyy ...yep it has helped especially 1,2 and 3. is 2 and 3 really that simple??..thought it would be complicated!! still a bit :confused:

about 4 tho.
thnx :smile:

Reply 168

pastpaper-guy

7

Original post by giraffegiraffe

ohhh yeah i see what you mean but gosh i hope not .. the not-straightforward questions are the worst! its so hard to try to realise what they want you to say. the pastpaper questions i've tried so far have been kindof straightforward in the way they're asked but its just getting those exact words in which is a killer!
is everyone using the black and purple ocr textbook?

using the cgp revision guide

Reply 169

Tabers

15

Original post by giraffegiraffe

is everyone using the black and purple ocr textbook?

Yeah thats the one I'm using as well as the little thin revision guide to go with it. But the revision guide hasn't got enough information so I just tend to use it for last minute quick revision and the questions.

Reply 170

PhoTaydo

1

Original post by pastpaper-guy

im just worried they will try to incorporate some of the syllabus into a real example. E.g they give you a question about the heart and talk about a kid who has a condition where the right atria has a hole in it.
Explain why the kid feels tired alot of the time?

not exactly like that but u get the point

Regarding that hypothetical question they might ask you to intepret a Electrocardiograph (ECG) and the shape of it, PQSRT

Reply 171

pastpaper-guy

7

Original post by PhoTaydo

Regarding that hypothetical question they might ask you to intepret a Electrocardiograph (ECG) and the shape of it, PQSRT

oh u reminded me. ecg was on my list.

can someone explain what each letter is on a ecg diagram?

Reply 172

giraffegiraffe

10

Original post by pastpaper-guy

oh u reminded me. ecg was on my list.

can someone explain what each letter is on a ecg diagram?

P=atrial systole
QRS=ventricular systole
T=ventricular diastole

(ie QRS and T are also atrial diastole)

yup i'm using the cgp revision guide too, its surprisingly good for this course i think! along with the black and purple ocr book.

(edited 13 years ago)

Reply 173

Konshi

Another exam to **** up. Nice.

Reply 174

786girl

Original post by pastpaper-guy

oh u reminded me. ecg was on my list.

can someone explain what each letter is on a ecg diagram?

ill talk about the unhealthy ones (this is in the book so i assume it could come up)

elevation of the ST section is an indicator of a HEART ATTACK

small & unclear P wave = ATRIAL FIBRILLATION -(dodgy heart beat pattern lol)

deep S wave = abnormal ventricular hypertrophy (muscle thickness increases)

Reply 175

Wilko94

6

Some quick notes on the movement of water through the xylem.

•

Water moves into the xylem down a water potential gradient.

•

Pressure from water entering the xylem via osmosis gives the bottom of the xylem a high hydrostatic pressure.

•

Transpiration at the leaves creates a low hydrostatic pressure at the top of the xylem.

•

Water, under tension, is pulled up in a continious column.

•

This is aided by: cohesion - the attraction of water molecules to each other, forming hydrogen bonds.

•

adhesion - the attraction of water molecules to the xylem wall.

•

Capillary action also aids the process - this is where the water rises because it is placed in a very narrow tube.

•

All of the above bullet points lead to the water moving up the xylem by mass flow, from a higher hydrostatic pressure to a lower hydrostatic pressure, down a pressure gradient.

Rep appreciated. :-)

(edited 13 years ago)

Reply 176

TattyBoJangles

19

Are things like heart block, ventricular fibrillation, bradycardia and tachycardia likely to come up? They're not in the book, but our teacher gave us a load of sheets which had those one?

Reply 177

Sam S

Okay...in the black and purple ocr book, it says normal adult cells of most eukaryotes contain two sets of chromosomes..? so each set contains 23 chromosomes right?, so if we were asked to draw a diagram of this.., what would you do? am i missing something?

Reply 178

giraffegiraffe

10

Original post by TattyBoJangles

Are things like heart block, ventricular fibrillation, bradycardia and tachycardia likely to come up? They're not in the book, but our teacher gave us a load of sheets which had those one?