8.1. The circulatory system
A subsection of Biology, 9700, through 8. Transport in mammals
Listing 10 of 175 questions
A red blood cell goes through a number of stages in the bone marrow before it is released into the circulation to carry out its role of oxygen transport. is a transmission electron micrograph of developing red blood cells in the bone marrow. Each cell is known as an erythroblast. shows erythroblasts at a higher magnification than can be obtained using the light microscope. Explain the advantages of using an electron microscope to obtain images such as that in . Describe the differences between an erythroblast and a mature red blood cell. The maturing red blood cell synthesises haemoglobin and other proteins. Complete Table 3.1 to: • name three organelles (cell structures) that are involved in the synthesis of a fully functioning protein • state one way in which the named organelle is involved in protein synthesis. Table 3.1 organelle how the organelle is involved in protein synthesis shows a reversible reaction that takes place within red blood cells. CO2 + H2O H2CO3 Name the protein that catalyses the reaction shown in . The SPTB gene codes for a protein that provides stability and support to the cell surface membrane of the red blood cell. Mutations in SPTB result in red blood cells that are spherical in shape. This mutation leads to a disease known as spherocytosis type 2. Suggest why a person with spherocytosis type 2 has a reduced ability to take up oxygen in the pulmonary capillaries compared with a person who has normal red blood cells. Increases in the water potential of the blood plasma have greater effects on red blood cells in people with spherocytosis type 2 than on normal red blood cells. Compare and explain the effects of an increase in the water potential of blood plasma on spherocytosis type 2 red blood cells and normal red blood cells.
9700_w19_qp_22
THEORY
2019
Paper 2, Variant 2
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The high blood pressure at the arterial end of a capillary network results in some components of blood leaving the capillaries and forming tissue fluid. At the venous end, the presence of plasma proteins allows movement of water by osmosis back into the capillaries. is a diagram showing a capillary network. The lymph vessels and the blood vessels at the arterial and venous ends of the network are also shown. tissue fluid body cells capillaries lymph vessel Red blood cells and plasma proteins, such as albumin, remain in the capillaries and are not found in tissue fluid. Explain why red blood cells and albumin do not leave the capillary. Name the chemical reagent or reagents used to test for proteins in a sample of blood plasma and state the colour change that will be seen if protein is present. reagent or reagents colour change When a person moves from sea level and stays at high altitude for a few months, there is an increase in the number of red blood cells per mm3 of blood. Explain why this increase occurs. A low blood albumin concentration can lead to a condition known as oedema. Oedema is a swelling of tissues caused by the accumulation of tissue fluid surrounding the body cells in the capillary network. Suggest and explain how a low blood albumin concentration can lead to oedema. Albumin transports some cell signalling molecules from the cells where they are synthesised to their target cells. The cell signalling molecules bind to specific cell surface membrane proteins on the target cells. Name the type of membrane protein to which the cell signalling molecules bind.
9700_w21_qp_22
THEORY
2021
Paper 2, Variant 2
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Questions Discovered
175