In vertebrates, smooth endoplasmic reticulum in cells of which organ plays a crucial role in detoxification of toxic compounds ?
- A.Spleen
- B.Intestine
- C.Kidney
- D.Liver
Correct answer
Explanation
The correct answer is D, Liver. The liver cells (hepatocytes) are rich in smooth endoplasmic reticulum, whose enzymes break down drugs, alcohol and poisons into harmless forms.
The endoplasmic reticulum is a network of membranes in the cytoplasm. The rough ER is studded with ribosomes and makes proteins, while the smooth ER has no ribosomes and makes lipids and steroids and carries out detoxification. In the liver, the smooth ER holds enzymes such as the cytochrome P450 family, which change fat-soluble toxins into water-soluble substances that the kidneys can then pass out in urine. Regular intake of alcohol or certain drugs makes the smooth ER in liver cells grow larger.
A is wrong: the spleen filters blood and removes old red blood cells; it is not the main detoxifying organ.
B is wrong: the intestine digests and absorbs food.
C is wrong: the kidney removes wastes that are already water-soluble but does not chemically detoxify them in this way.
Exam tip: rough ER = protein synthesis; smooth ER = lipids and detoxification, best developed in liver cells.
Practice Questions
View allWhich one of the following frequency ranges is sensitive to human ears ?
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- B.20-20,000 Hz
- C.200-20,000 Hz only
- D.2,000-20,000 Hz only
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- C.Petrol
- D.Wax
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- A.Caesium
- B.Potassium
- C.Calcium
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Read the full explanation →Which of the following sets of elements has the same valency?
- A.Na, Mg, Ca
- B.Na, Mg, Al
- C.Mg, Ca, K
- D.Mg, Ca, Ba
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