What is tissue?
- A.Cells which are similar in origin but dissimilar in form and function.
- B.Cells which are dissimilar in origin but similar in form and function.
- C.Cells which are dissimilar in origin, form, and function.
- D.Cells which are similar in origin, form, and function.
Correct answer
Explanation
The correct answer is D, cells which are similar in origin, form and function. A tissue is a group of cells that come from the same source, look alike and work together at one job. The dividing of labour among tissues is what allows a large body to work well: muscle tissue contracts, nerve tissue carries messages, and blood, a fluid connective tissue, carries oxygen and food. Animals have four main kinds of tissue, epithelial, connective, muscular and nervous. Plants have meristematic tissue, whose cells keep dividing at root and shoot tips, and permanent tissue such as parenchyma, collenchyma and sclerenchyma. Several tissues working together make an organ, and organs make an organ system. A, B and C are wrong because each drops one of the three conditions; cells of one tissue must match in all three, in origin, in form and in the work they do. Exam tip: tissue, organ, organ system, organism, in that order.
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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