All Free Biology MCQs with Answers
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19844 questions · page 638 of 1985
6371. Double membranous structures having coins-like stacks of membranes are Known as:
- A. Mitochondria
- B. Nucleus
- C. Chloroplast
- D. Golgi apparatus
Explanation: Chloroplasts contain thylakoids, which are organized into grana. Each granum appears like a stack of coins, and the entire structure is enveloped by a double membrane.
Correct answer: Chloroplast6372. Plants store food in:
- A. Chloroplast
- B. Chromoplasts
- C. Leucoplast
- D. Both A and B
Explanation: Leucoplasts are colorless organelles found in nonphotosynthetic tissues of plants. They specialize in storing essential nutrients such as starch, oils, and proteins, making them key sites for food storage in plants.
Correct answer: Leucoplast6373. A disease caused by the absence of a lysosomal enzyme responsible for lipid catabolism:
- A. Tay-Sachs disease
- B. Phenylketonuria
- C. Klinefelter syndrome
- D. Down syndrome
Explanation: Tay-Sachs disease is a genetic disorder caused by the absence of a vital lysosomal enzyme responsible for breaking down certain lipids. This deficiency leads to the accumulation of lipids in nerve cells, which impairs brain function.
Correct answer: Tay-Sachs disease6374. The process of self-digestion of selective nonfunctional organelle by cells through the actions of enzymes originating from the cell is called?
- A. Pinocytosis
- B. Endocytosis
- C. Autophagy
- D. Cytotoxicity
Explanation: Autophagy is a cellular mechanism for self-digestion where cells degrade and recycle their own components, such as nonfunctional organelles, using enzymes. This process is essential for cellular maintenance and energy regulation, particularly during stress conditions.
Correct answer: Autophagy6375. Lipid metabolism is the function of:
- A. Ribosomes
- B. Sarcoplasmic reticulum
- C. Rough Endoplasmic Reticulum (RER)
- D. Smooth Endoplasmic Reticulum (SER)
Explanation: The Smooth Endoplasmic Reticulum (SER) is responsible for lipid metabolism, including the synthesis of lipids and detoxification processes.
Correct answer: Smooth Endoplasmic Reticulum (SER)6376. Some cellular organelles are bounded by a single membrane, while others have two membranes around them. Which one of the following is correct?
- A. Vacuole and lysosome are single membrane-bounded; nucleus and chloroplast are double membrane-bounded
- B. Chloroplast and lysosome are double membrane-bounded; vacuole and nucleus are single membrane-bounded
- C. Nucleus and vacuole are double membrane-bounded; chloroplast and lysosome are single membrane-bounded
- D. Vacuole and chloroplast are single membrane-bounded; nucleus and lysosome are double membrane-bounded
Explanation: The correct answer is that vacuoles and lysosomes are single membrane-bounded organelles, while the nucleus and chloroplast are double membrane-bounded. The other options incorrectly pair organelles with their membrane structures. Understanding the basic structure of these organelles is crucial for distinguishing between them.
Correct answer: Vacuole and lysosome are single membrane-bounded; nucleus and chloroplast are double membrane-bounded6377. _ is involved in lipid synthesis/metabolism.
- A. Smooth endoplasmic reticulum
- B. Rough endoplasmic reticulum
- C. Mitochondria
- D. Vacuoles
Explanation: 'Smooth ER' is involved in lipid synthesis and metabolism. 'Rough ER' is involved in protein synthesis. The main job of 'mitochondria' is to perform cellular respiration. This means it takes in nutrients from the cell, breaks them down, and turns them into energy.'Vacuoles', on the other hand, are organelles that exist mainly to isolate potentially harmful waste materials. They do their task effectively by simply engulfing the waste material.
Correct answer: Smooth endoplasmic reticulum6378. The idea that opposed the idea of abiogenesis was proposed by?
- A. Robert Hooke
- B. Robert Brown
- C. Rudolph Virchow
- D. Lorenz Oken
Explanation: Rudolph Virchow gave statement according to the cell theory that new cells are formed from division of pre-existing cells which opposed the concept of abiogenesis.
Correct answer: Rudolph Virchow6379. Lysosomes function in:
- A. Protein synthesis
- B. Processing of cellular materials
- C. Intracellular digestion
- D. Lipid synthesis
- E. Carbohydrate synthesis
Explanation: Lysosomes are specialized organelles within the cell that contain hydrolytic enzymes capable of breaking down macromolecules like proteins, nucleic acids, lipids, and carbohydrates. Their primary function is intracellular digestion, where they degrade and recycle cellular waste, damaged organelles, and material ingested by the cell. Unlike ribosomes, lysosomes do not synthesize proteins, and they are not involved in lipid or carbohydrate synthesis, which occur in other organelles. Options such as 'protein synthesis', 'lipid synthesis', and 'carbohydrate synthesis' refer to processes that take place outside of lysosomes, highlighting their specialized role in cellular maintenance through digestion.
Correct answer: Intracellular digestion6380. Which of the following is NOT a difference that would allow one to distinguish between a prokaryotic and a eukaryotic cell? Presence or absence of the nucleus Presence or absence of the cell wall Membrane-bound versus non-membrane-bound organelles
- A. I only
- B. II only
- C. III only
- D. I and II only
- E. I, II and III
Explanation: Eukaryotic cells have nucleus and membrane-bound organelles, which is not the property of prokaryotes.The cell wall is not a distinguishing feature between prokaryotes or eukaryotes. because animal cell is eukaryotic and does not have cell wall
Correct answer: II only