OCR Biology F211 resit - 16th May

I am resitting this for the 4th time, i think i might be the only person in the World. I just dont get it. I got an A first time in F212. what am i doing wrong in this paper *slams head into wall*

Hey I have the 2011 paper, mark scheme and insert (except the insert exceeds the upload limit?). This is the third time I'm resitting as I got exactly the same mark the previous two times round which got me an E. The insert is a picture of a eukaryote cell and a steaming cut branch. The steaming branch picture is pretty pointless as it doesn't really help you answer the question and the mark scheme wants you to basically talk about the xylems adaptations. I wouldn't try to guess what comes up on the paper as only the person that writes it knows! but they can only ask you stuff on the spec unless you get the often strange how science works questions that might pop up. My guesses are:
A question involving the xylem and/or phloem (e.g. structure, transpiration, location of them in roots or stem, xerophytes ect)
The heart or something related to it such as veins, capillaries, arteries, circulatory systems, AVN, SAN even gaseous exchange
This would also tie in with the lungs (e.g. Bohr effect, structure, adaptations, surface area to volume ratio, spirometer, inhaling, exhaling ect)
Quite possibly cell division, mitosis question this has come up in almost every paper but one
Also something to do with cells/ microscopes so eukaryotes/prokaryotes, resolution, calculating magnification, cell organelles, cytoskeleton, plasmolysis, cell surface membrane (plasma membrane), glycoproteins,

Basically get the spec off OCR's website grab your textbook or notes and check you know everything it states.

The Bohr effect
Large, active organisms need a circulatory system because they have a small surface area to volume ratio. Haemoglobin is a pigment found in red blood cells. These cells are also known as erythrocytes . Haemoglobin has a high affinity for oxygen. In the lungs, the haemoglobin associates with oxygen to form oxyhaemoglobin. In respiring tissues, the oxygen is released by dissociation. In very active tissues, the amount of oxygen released can be increased by the presence of more carbon dioxide .
This is called the .................... effect. [6]
Basically oxygen is transported around the body by binding to haemoglobin, when you need to respire quickly e.g. when exercising the amount of CO2 in the body increases and produces more hydrogen ions, this diffuses into red blood cells and causes the oxygen to be released by dissociating it from the haemoglobin. On a dissociation curve this is shown by it moving down and too the right.

Tissue fluid is the fluid that leaves the capillaries as blood flows through them this consists of blood containing plasma, dissolved nutrients and oxygen which are small enough to diffuse through when put under high pressure from the heart contracting (hydrostatic pressure). Excess tissue fluid then drains into the lymphatic system.

Hope I've cleared a few things up for people and sorry for the really long message

Can anyone explain to me how to calculate magnification? thanks

can anyone tell me the importance of the cellsurface membrane??

anyone know the structure and function of; epithilial cells, palisade cells, root hair cells and neutrophils.. ? Any help would be greatly appreciated.

Revising Heart because nothing about the heart came up in the January 2011 paper