8.2. Transport of oxygen and carbon dioxide
A subsection of Biology, 9700, through 8. Transport in mammals
Listing 10 of 241 questions
The mammalian circulatory system is adapted for the long-distance transport of the respiratory gases, oxygen and carbon dioxide. The system is described as a closed double circulation. Name: • the two different circulations of the double circulatory system of mammals • the main vein returning deoxygenated blood to the heart. In a closed circulation, blood is kept within vessels at all times. Name the type of blood vessel that connects capillaries and veins. is a diagram of a section through the heart. On : • add a label line and the letter L to show the artery that takes blood from the heart to the lungs • add a label line and the letter R to show the valve that closes when the right ventricle is in systole. The entry of carbon dioxide into red blood cells results in the production of hydrogencarbonate ions. This involves the enzyme carbonic anhydrase. Complete the passage summarising the production of hydrogencarbonate ions by: • writing the correct biological term in the spaces provided • writing the molecular formula for two of the terms in the spaces in brackets. Carbonic anhydrase has an overall spherical shape and is known as a protein. The enzyme acts within the cell so can be described as an enzyme. When blood passes into the capillary network through actively respiring tissues, carbon dioxide (CO2) diffuses into red blood cells and carbonic anhydrase catalyses a reaction where ( ) is combined with CO2 to form (H2CO3), which rapidly forms ions ( ) and hydrogencarbonate ions (HCO3 –).
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THEORY
2022
Paper 2, Variant 2
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shows some of the events that occur when a red blood cell flows through a capillary in the lungs. Cl – HCO3 – HCO3 – + H+ H2CO3 CO2 + H2O CO2 O2 HbO2 + H+ X + O2 carbonic anhydrase plasma red blood cell State why there are transport proteins in the membranes of red blood cells to allow the movement of hydrogencarbonate ions (HCO3 –) and chloride ions (Cl –). shows that chloride ions move out of the red blood cells. Explain why this movement is necessary when red blood cells flow through capillaries in the lungs. State why carbon dioxide molecules diffuse from the red blood cells into the plasma. State the name of the compound indicated by X.
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THEORY
2022
Paper 2, Variant 3
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Scientists measured the concentration of sodium ions and potassium ions in the red blood cells and in the blood plasma of a group of people. The results are shown in Table 1.1. Table 1.1 mean concentration of sodium ions / mmol dm–3 mean concentration of potassium ions / mmol dm–3 red blood cells blood plasma Use the information in Table 1.1 to identify and describe the process by which potassium ions enter red blood cells from the blood plasma. Sodium ions and oxygen molecules enter red blood cells. State one similarity and one difference between the processes used by sodium ions and oxygen molecules to enter red blood cells. similarity difference Chloride ions move across the membrane of human red blood cells in a process called the chloride shift. Explain why the chloride shift is important in the transport of carbon dioxide from respiring tissues. Scientists studied the uptake of a substance, F, by human red blood cells. The red blood cells were immersed in a solution of substance F for 30 minutes. After this time the scientists recorded two observations: • the cell surface membrane of the red blood cells showed infoldings • an increase in the number of vesicles in the cytoplasm. Identify the process by which substance F entered the red blood cells.
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THEORY
2023
Paper 2, Variant 1
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Questions Discovered
241