Kayleejarv24
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What are the specialised ultrastructures that allow a red blood cell to carry out its role?

can anyone help me out on this question please I don't know what to put
would be much appreciated.
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shomoysha
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Ultra structure refers to the cell. I think it might be talking about how blood is specialised (no nucleus, donut shaped)
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Kayleejarv24
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(Original post by shomoysha)
Ultra structure refers to the cell. I think it might be talking about how blood is specialised (no nucleus, donut shaped)
I’m not sure lol, but I’m just confused on what to write for the questions.
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macpatgh-Sheldon
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Hi Kaylee.*

Yes, Shom.* is correct, but you could do with an explanation PLUS some other points.

The absence of a nucleus in an erythrocyte (Greek eryth = red; cytos = container here cell SO red blood cell) means that it can carry more haemoglobin to bind oxygen.
The flattened doughnut shape means that there is a large surface area for exchange of gases (in a Q like this show off your knowledge by brief mention of O2 and CO2 exchange in the tissues AND in the lungs).

The diameter of the RBC (about 7 microns [micrometres = 10^-6 m]) is similar to the diameter of the capillaries, so the RBC just squeezes through -----> slow passage of RBC means more time for gas exchange BUT ALSO there is a very short distance for O2 to diffuse across = capillary wall (unicellular - one cell thick ONLY) and RBC cell membrane (also very thin = 7 nm (nanometres = 10^-9 m) (plus v thin alveolar wall in the lungs).

The fact that the RBCs are minute and that there are a few million of them per square mm of blood (4-5 million in a male, slightly less in a female) also vastly increases the surface area for gas exchange.

The cell membrane of the RBC is very specialized (like no other cell in the body) which makes it survive immense mechanical and osmotic forces as it squeezes through capillaries - it is v flexible and v strong due to the arrangement of specialized proteins helically (sort of in minute spirals) e.g. a protein called spectrin and another called adhesin. During the 90 day life cycle of a RBC, it travels many thousands of miles in the circulation.

The section is italics is beyond A level, but would impress your examiner in the synoptic Q at A2 if you are aiming for an A* - if not, don't worry if you can't remember it.

M.
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Kayleejarv24
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(Original post by macpatgh-Sheldon)
Hi Kaylee.*

Yes, Shom.* is correct, but you could do with an explanation PLUS some other points.

The absence of a nucleus in an erythrocyte (Greek eryth = red; cytos = container here cell SO red blood cell) means that it can carry more haemoglobin to bind oxygen.
The flattened doughnut shape means that there is a large surface area for exchange of gases (in a Q like this show off your knowledge by brief mention of O2 and CO2 exchange in the tissues AND in the lungs).

The diameter of the RBC (about 7 microns [micrometres = 10^-6 m]) is similar to the diameter of the capillaries, so the RBC just squeezes through -----> slow passage of RBC means more time for gas exchange BUT ALSO there is a very short distance for O2 to diffuse across = capillary wall (unicellular - one cell thick ONLY) and RBC cell membrane (also very thin = 7 nm (nanometres = 10^-9 m) (plus v thin alveolar wall in the lungs).

The fact that the RBCs are minute and that there are a few million of them per square mm of blood (4-5 million in a male, slightly less in a female) also vastly increases the surface area for gas exchange.

The cell membrane of the RBC is very specialized (like no other cell in the body) which makes it survive immense mechanical and osmotic forces as it squeezes through capillaries - it is v flexible and v strong due to the arrangement of specialized proteins helically (sort of in minute spirals) e.g. a protein called spectrin and another called adhesin. During the 90 day life cycle of a RBC, it travels many thousands of miles in the circulation.

The section is italics is beyond A level, but would impress your examiner in the synoptic Q at A2 if you are aiming for an A* - if not, don't worry if you can't remember it.

M.
So I can put that as my answer but reword it.
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macpatgh-Sheldon
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Yes you can - just make sure you understand all I have said (if stuck on anything, please feel free to message me - (I shall try to explain things in a different way to help you understand and I can give you tips on memory skills, too)) (because it is more important to grasp the concepts as over time when you do your actual exams, the cumulative skills you develop over the whole A level course are what helps achieve super grades, not just short-term success) AND decide on the length/otherwise of your answer based on how many marks it is worth - is this a short structured Q worth 4-6 marks? I would think so, and in that case, keep it clear and concise.

Hope you get full marks!
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Kayleejarv24
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That would be brilliant if you could help me out on this. I really want to do well on this as this is my assignment and want to get a good mark on it I also got to description of the stages of mitosis and the important processes that happens in each stage Any help would be much appreciated
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Kayleejarv24
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(Original post by macpatgh-Sheldon)
Yes you can - just make sure you understand all I have said (if stuck on anything, please feel free to message me - (I shall try to explain things in a different way to help you understand and I can give you tips on memory skills, too)) (because it is more important to grasp the concepts as over time when you do your actual exams, the cumulative skills you develop over the whole A level course are what helps achieve super grades, not just short-term success) AND decide on the length/otherwise of your answer based on how many marks it is worth - is this a short structured Q worth 4-6 marks? I would think so, and in that case, keep it clear and concise.

Hope you get full marks!
I am doing an access to nursing course and it I have 10 question altogether and the whole thing can only be 1600 words and I’m scared I’m gonna get all this wrong and not get the grades I want.
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