The lymph is mainly formed from the plasma of blood and it surrounds the cells. The main difference between blood and lymph is :
- A.Lymph does not contain red blood cells.
- B.Lymph does not contain white blood cells.
- C.Lymph contains both red blood cells and white blood cells.
- D.Lymph does not contain any cells.
Correct answer
Explanation
The correct answer is A, Lymph does not contain red blood cells. Lymph is plasma that has leaked out of the capillaries, and red blood cells are too large to pass through the capillary walls.
As blood flows through the capillaries, part of the plasma with small proteins and some white blood cells seeps into the spaces between the cells; this tissue fluid is called lymph once it enters the lymph vessels. It is colourless or pale yellow because it has no haemoglobin-carrying red cells. Lymph is rich in lymphocytes, a kind of white blood cell, which multiply in the lymph nodes and fight infection. Lymph vessels also carry fats absorbed by the lacteals of the small intestine and return the fluid to the blood near the heart.
B is wrong: lymph does contain white blood cells, chiefly lymphocytes.
C is wrong: red blood cells are absent from lymph.
D is wrong: lymph is not cell-free, since it carries lymphocytes.
Exam tip: lymph = plasma + lymphocytes, no RBCs and no platelets in useful numbers; it is colourless and flows one way, back to the heart.
Practice Questions
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- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
Show answer
In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
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- 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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- 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
Show answer
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- 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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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.
Show answer
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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