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When differences between prokaryotes and eukaryotes are taught in an introductory biology course, a generic prokaryotic cell and a generic eukaryotic cell are typically compared. Cells in a complex multicellular organism, like a human, are quite diverse. Human red blood cells are one example of a highly specialized cell with a mature form that is quite ...


19

Red blood cells are produced in the red marrow which... "is found mainly in the flat bones, such as the pelvis, sternum, cranium, ribs, vertebrae and scapulae, and in the cancellous ("spongy") material at the epiphyseal ends of long bones such as the femur and humerus." - Wikipedia So you are partly right; the femur is associated with red blood ...


19

Hemoglobin molecules used to manufacture these products are not contained by a red cell membrane, and when released into the vasculature, these molecules rapidly scavenge nitric oxide.This can result in systemic vasoconstriction, decreased blood flow, increased release of proinflammatory mediators and potent vasoconstrictors, and a loss of platelet ...


16

Good question! Let's start with an overview and explanation of the ABO blood grouping system (Dean, 2005): Blood groups, antigens and antibodies: Subjects with blood group A carry the A antigen on their red blood cells (RBCs) and have antibodies to antigen B; subjects with blood group B have the B antigen and anti-A antibodies, blood group AB carries both ...


13

No. Nobody considers red blood cells to be prokaryotic, perhaps most importantly because they are part of a eukaryotic organism. Red blood cells begin life with the full complement of organelles, including a nucleus and mitochondria, but our RBCs shed their organelles during maturation. In actuality, though, only mammalian RBCs lack nuclei; other animals' ...


12

The "purest of all blood" is fresh out of the bone marrow, i.e. in your circulatory system. Menstrual blood is a combination of blood, some mucous, and dead endometrial tissue. The endometrium consists of a single layer of columnar epithelium resting on the stroma, a layer of connective tissue that varies in thickness according to hormonal influences. ...


12

To the man with a hammer, everything looks like a nail. The poster’s hammer seems to be kidney function. Mine is the biochemistry of the erythrocyte (red blood cell). Others, no doubt will be able to provide yet different perspectives. From a biochemical point of view the erythrocyte has a limited repertoire of metabolic pathways compared with other ...


11

In humans (and all mammals), red blood cells lack mitochondria and therefore has no functional TCA cycle. They metabolize glucose mainly via glycolysis, forming lactate which is released from the cells; this yields 2 ATP for each glucose molecule, much less than complete oxidation (ca 30 ATP), but enough to support the red blood cells' energy needs. There ...


11

No. Prokayotic cells are full organisms with their own DNA, red blood cells are not.


10

They do not, at least not normally or noticeably. MHC I occurs on all nucleated cells, and red blood cells do not have nuclei. If they did indeed have MHC on them, blood transfusions would be as successful and as tricky as organ donation. There are reports of MHC detection on red blood cells, but the amount is orders of magnitude smaller than elsewhere, ...


9

Snails, like most molluscs, have a protein called hemocyanin dissolved directly in the hemolymph ("blood"). Hemocyanins are copper-containing metalloproteins: the binding site for a single O2 molecule contains two copper atoms. Unlike hemoglobin, where reversible oxygen binding is accomplished without a change in the oxidation state of the Fe(II) atoms in ...


9

An additional aspect is that the availability of iron usually constrains the growth of pathogens. Cassat and Skaar in "Iron in Infection and Immunity" state: Iron is an essential nutrient for both humans and pathogenic microbes.... Given the absolute requirement for iron by virtually all human pathogens, an important facet of the innate immune system is ...


8

A few components to my answer. Red blood cells do not contain a nucleus, therefore, they do not harbour DNA. The major determinant of blood compatibility is the blood antigen. There are only 4 types: O, A, B, AB. This is genetically encoded, and is expressed as a set of sugar coats on the blood cell membrane. However, the enzymes that encode for A or B ...


8

Reticulocyte stage is when the ribosomes are still present and after that no new protein synthesis occurs. However RBCs have a lot of proteins and major proteins other than haemoglobin are cytoskeletal proteins and ion channels/pumps (In fact, cytoskeletal proteins are more abundant than haemoglobin). It is the Na+-K+-ATPase that consumes most ATP. As you ...


8

The reason why the cell would shrink more in CaCl2 solution is because it has a higher van't Hoff factor i.e. total number of dissociated ionic species per solute molecule (it is 2 for NaCl whereas it is 3 for CaCl2). (Nonionic solutes do not dissociate and will therefore have a van't Hoff factor of 1) Osmotic pressure (and other colligative properties) ...


7

Q. “What problems (if any) arise when the iron is oxidised?” A. Haemoglobin will be converted to methaemoglobin which cannot bind oxygen. To quote from the article on Methaemoglobin in Wikipedia: Methemoglobin (English: methaemoglobin) (pronounced "met-hemoglobin") is a form of the oxygen-carrying metalloprotein hemoglobin, in which the iron in the ...


7

No. If they did, blood transfusions wouldn't be possible (or they would require some sort of direct body-to-body system). Red cells collected can be stored under refrigeration for over a month. See for example the description of what happens to donated blood from the Red Cross. Platelets don't last quite as long, but they also survive for some time in the ...


6

They are recycled, the iron and other components are broken down and then absorbed. Adaptations of the RBC prevent the same RBC being used. They lack a nucleus to make them highly efficient oxygen carriers (pack as much haemoglobin as possible). Without a nucleus and other organelles they're unable to synthesise the stuff they'd need for renewal. There's a ...


6

This is a well worded question. There are more reasons than the following but the most apparent is hemoglobin production and its transport. The erythrocyte is a cell whose structure is optimal for its function-the production and transport of hemoglobin. It lacks a nucleus and organelles so that it can devote almost 100% of its energy to hemoglobin ...


5

The blood type of people is determined by proteins which are anchored into the surface of the red blood cells. Cells can either express the A, B, A and B or no marker, resulting in the blood groups A, B, AB and 0. People which have a certain blood type (for example A) have antibodies against the other blood type (in this case B). This will lead to the ...


5

It happens, but it is very rare. Anti-A and Anti-B antibodies are IgM type. They do no cross the placenta. Sometimes IgG can be produced and lead to the hemolytic disease of the newborn. Anti-D antibodies are IgG type and can pass through the placenta.


5

The molecular basis of copper-transport diseases in Trends in Molecular Medicine, Volume 7, Issue 2, 1 February 2001, Pages 64–69, has a link to a 1973 paper by JM Gillespie entitled "Keratin Structure and Changes with Copper Deficiency," stating Menkes patients are often diagnosed from their unusual hair structure – termed pili torti – also known as ...


5

The reason why blood is red is rather simple: It is the iron atom in the middle of the heme, which plays the central part in binding oxygen. Depending on the oxidation state the blood looks either dark or light red. The structure is the following (taken from here): That the color only depends on the coordinated metal atom is shown by another related ...


5

Yes. This is true. During the final stages of red blood cell formation in the bone marrow, the nucleus and several other organelles are broken down and/or expelled from the cells. In the process they decrease markedly in size, from about 24 to about 7-9 micrometer. Presumably this makes them small enough to pass through the smallest capillaries. Lacking ...


5

It depends on what you call "to live". RBCs cannot divide, for instance. They cannot synthesise proteins either, so they are decaying after their nucleus is expelled. But they produce ATP using anaerobic glycolysis (as they lack mitochondria), which you may take as a characteristic of "living".


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Camel RBCs are anucleate [1, 2]. The dark structure seen in microscopic images is not nuclei but a network of microtubules called the marginal bands. Marginal bands cause these RBCs to adopt an ellipsoid shape. The unique shape of these RBCs possibly allows them to survive osmotic stress and is probably advantageous to a camel under extreme dehydration. ...


5

The hematopoietic stem cells are quite rare, and each progenitor cell produced by a stem cell gives rise to a large number of red blood cells (and other blood cell types). I'm not sure if the precise number of offspring for the earliest progenitor cells is known in vivo, but recent cell culture models indicate that early progenitors can give rise to as many ...


5

No. Your supposition is incorrect — the phosphate in glyceraldehyde 3-phosphate has to come from somewhere, and it comes from glucose 6-phosphate. The reason a second ATP is required before you get to the triose phosphate stage in glycolysis is that you are generating two molecules of triose phosphate. In the pentose phosphate pathway (energy-producing non-...


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