Competition - post a photo you've taken of nature >>

F211 revision thread.

Scroll to see replies

Reply 80

TheSnail

Heya peeps, i'm sitting this exam (first time)

Should be okay I think :smile:

Reply 81

Smuu

Original post by NOONA.

Does anyone have any idea, what topics came up in January's paper?

I did the mock! The Qwc questions were cell signalling and tissues ( like tissues leading to organs then organ systems etc). Also yeast came up and the potometer but this question was how science works type. Also a lot on transport system and surface area:volume ratio questions :smile:

Posted from TSR Mobile

Reply 82

ladybug.hugsxoxo

Original post by scorpio22

Hi.head of biology.made a predictions PowerPoint. I can Send it to you through email if you would like.last time 40% came up on what she guessed,not guaranteed to all come up but since you will b revising anyway it won't hurt to learn these particular topics in depth.

Sorry for being a pain but would u just be gem and write down the topics for me won't be able to access the PowerPoint from my phone xx

Posted from TSR Mobile

Reply 83

pyaesone

Can someone explain to me about oxygen dissociation curve and Bohr effect? It wasn't asked for many years and I think it could be asked this year.

Reply 84

otrivine

Original post by pyaesone

Can someone explain to me about oxygen dissociation curve and Bohr effect? It wasn't asked for many years and I think it could be asked this year.

It illustrates for example if the level of co2 increases more oxygen is released from the red blood cells and this is why you see the curve shifting to right but if less co2 present less oxygen is released from RBC which shows the curve is on the left side

Reply 85

ellexo

Hello everyone :smile:

Im a little bit confused about carrier proteins in membranes. Do they always require ATP to transport substances?

Reply 86

otrivine

Original post by ellexo

Hello everyone :smile:

Im a little bit confused about carrier proteins in membranes. Do they always require ATP to transport substances?

Hi do you want to revise asking each other questions :smile:

Yes because the active transport consist of these carrier protein in order to carry large molecules against its concentration gradient and hence, because it is moving in opposite direction it always needs energy and ATP is hydrolysed to ADP and an inorganic phosphate group.

Reply 87

ellexo

Ann thanks so much! Yep sure I'll start :smile:

outline the sequence of events following the production of extracellular proteins that leads to their release from the cell?

Ahh* lol

Original post by ellexo

Ahh* lol

Describe what happens when you place an red blood cell in Hypertonic solution (3)

Reply 90

otrivine

Original post by ellexo

Ann thanks so much! Yep sure I'll start :smile:

outline the sequence of events following the production of extracellular proteins that leads to their release from the cell?

The proteins are made in the ribosomes specifically in the Rough endoplasmic reticulum as the DNA that contains the genetic information codes for the protein this is by the Mrna molecule leaving the nucleus via nuclear pore and attaches to the ribosomes for protein synthesis to take place. The protein molecule is then modified and packages the protein into vesicles in Golgi apparatus and the vesicle then moves against its concentration gradient (movement by cytoskeleton) and fuses with plasma membrane which results in the protein being released out of the cell/

Reply 91

ellexo

Original post by otrivine

Describe what happens when you place an red blood cell in Hypertonic solution (3)

Due to the lower water potential in the hypertonic solution, water will move out of the Rbc as it moves from an area of high water potential to an area of low water potential and so the cell becomes crenated. Explain why there is a delay of the wave of excitation at the AVN?

Reply 92

Majeue

Original post by upthegunners

Hello friends and foes.

This is a thread dedicated to the mighty exam OCR have decided to creatively name "F211"

Ask each other exam questions (hard ones) that you happen to come across.

Or if you have any other questions just talk about them below.

Thank you and have a good evening! P.S

Spoiler

I'd say F212 is more of a killer, but thankfully there's still a while and half term before that.

Reply 93

otrivine

Original post by ellexo

Excellent

This is because it finishes the atria contraction in order for blood to pass through the ventricles in order for another wave of excitation to be initiated.

Reply 94

ellexo

Original post by otrivine

Excellent

This is because it finishes the atria contraction in order for blood to pass through the ventricles in order for another wave of excitation to be initiated.

Yepp and also to make sure all the blood empties into the ventricles before they contract.

Reply 95

otrivine

Original post by ellexo

Yepp and also to make sure all the blood empties into the ventricles before they contract.

Okay

Give 2 advantages of microscope

Reply 96

ellexo

Original post by otrivine

Okay

Give 2 advantages of microscope

Detailed images of cells can be seen and with SEM 3d images can make very smal objects detailed? Not sure about this one :/. State two functions on glycoproteins on membranes.

Reply 97

otrivine

Original post by ellexo

Detailed images of cells can be seen and with SEM 3d images can make very smal objects detailed? Not sure about this one :/. State two functions on glycoproteins on membranes.

correct

Cell recognition

forms cell surface receptor which is complementary in shape to a specific molecule which could be a hormone

Reply 98

LaughingGas

Question anyone can answer:

Explain why multicellular organisms need a transport system. [3 Marks]

Reply 99

otrivine

Original post by LaughingGas

Question anyone can answer:

Explain why multicellular organisms need a transport system. [3 Marks]

This is because multiceullar organisms have a smaller surface area to volume ratio and therefore simple diffusion is not adequate to meet their needs and in humans for example they have lots of epithelial cell so substances cannot diffuse into and out of the cell. Therefore, need mass transport system to meet their needs in order for organisms to obtain nutrients such as o2 and glucose