Which side of the human heart receives abundant oxygen-rich blood from the lungs?
- A.Left atrium
- B.Right ventricle
- C.Left ventricle
- D.Right atrium
Correct answer
Explanation
The correct answer is A, Left atrium. The left atrium is the chamber that receives oxygen-rich blood coming back from the lungs through the pulmonary veins. From there the blood passes the bicuspid or mitral valve into the left ventricle, which pumps it out through the aorta to the whole body. The right side of the heart handles the used blood: the right atrium takes oxygen-poor blood from the body through the vena cava, and the right ventricle sends it on to the lungs through the pulmonary artery. The left ventricle has the thickest wall of the four chambers because it must push blood the farthest. B is wrong because the right ventricle pumps blood to the lungs instead of receiving it from them. C is wrong because the left ventricle gets that blood next, from the left atrium, not straight from the lungs. D is wrong because the right atrium receives deoxygenated blood. Exam tip: pulmonary veins carry oxygen-rich blood to the left atrium, and the pulmonary artery is the one artery carrying oxygen-poor blood.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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