Which one of the following organelles is found in both prokaryotic and eukaryotic cells?
- A.Nucleus
- B.Mitochondria
- C.Ribosome
- D.Golgi complex
Correct answer
Explanation
The correct answer is C, Ribosome. Ribosomes make proteins, a job every living cell must do, so they are present in both prokaryotic and eukaryotic cells. Ribosomes are not bound by a membrane. Prokaryotes such as bacteria have smaller 70S ribosomes, while eukaryotes have 80S ribosomes in the cytoplasm and 70S ribosomes inside their mitochondria and chloroplasts. Because they have no membrane, ribosomes are found even in cells that lack all the membrane-bound organelles. Option A is wrong because a true nucleus with a nuclear membrane is the very feature prokaryotes lack; their DNA lies in a nucleoid region. Option B is wrong because mitochondria are membrane-bound organelles found only in eukaryotic cells. Option D is wrong because the Golgi complex is also a membrane-bound organelle, absent in bacteria and other prokaryotes. Exam tip: ribosome = common to all cells; prokaryote 70S, eukaryote 80S.
Practice Questions
View allWhich one of the following statements about the law of conservation of mass is correct?
- A.A given compound always contains exactly same proportion of elements.
- B.When gases combine in a reaction, they do so in a simple ratio by volume, provided all gases are at room temperature.
- C.Matter can neither be created nor destroyed.
- D.Equal volumes of all gases at same temperature and pressure contain equal number of molecules.
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The law of conservation of mass, stated by Antoine Lavoisier in 1789, says that in a chemical reaction mass is neither created nor destroyed.
Read the full explanation →On exposure to moist air, copper gains a green coat on its surface due to formation of which one of the following compounds ?
- A.Copper carbonate
- B.Copper oxide
- C.Copper sulphate
- D.Copper nitrate
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When copper is left in moist air for a long time, it slowly reacts with oxygen, water vapour and carbon dioxide.
Read the full explanation →Mirage is an illustration of
- A.only dispersion of light.
- B.only reflection of light.
- C.only total internal reflection of light.
- D.both refraction and total internal reflection of light.
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On a hot day the air just above a road or desert sand is much hotter, and so optically rarer, than the air higher up.
Read the full explanation →Which one of the following pairs of elements is liquid at room temperature and at normal pressure ?
- A.Gallium and Bromine
- B.Mercury and Bromine
- C.Gallium and Mercury
- D.Gallium and Caesium
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At room temperature and normal pressure only two elements are liquids: mercury, a metal, and bromine, a non-metal. Mercury melts at about −39 °C and is used in thermometers and barometers because it stays liquid over a wide range and does not wet glass.
Read the full explanation →Which one of the following salts does not possess water of crystallization?
- A.Potassium permanganate
- B.Blue vitriol
- C.Washing soda
- D.Mohr's salt
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Potassium permanganate, KMnO₄, forms dark purple crystals that contain no water of crystallization; its formula has no attached water molecules.
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