All Free Biology MCQs with Answers
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19844 questions · page 636 of 1985
6351. The inner membrane of the mitochondria is, usually, highly convoluted forming a series of infoldings known as
- A. Thylakoids
- B. Lamellae
- C. Cristae
- D. Grana
Explanation: Cristae are the infoldings of the inner membrane in mitochondria, increasing surface area for cellular respiration and ATP production.
Correct answer: Cristae6352. Besides giving out secretory vesicles, the Golgi apparatus is also concerned with the formation of:
- A. Lysosomes
- B. Plastids
- C. Grana of chloroplasts
- D. Protein synthesis
Explanation: Golgi body is the series of flattened stacks which has two faces: cis and trans. The cis face of a Golgi stack is the end of the organelle where substances enter from the endoplasmic reticulum for processing, while the trans face is where they exit in the form of smaller detached vesicles. The trans face secretes lysosomes and secretory granules.
Correct answer: Lysosomes6353. In plant cells, peroxisomes are associated with:
- A. Photorespiration
- B. Phototropism
- C. Photoperiodism
- D. Photosynthesis
Explanation: Peroxisomes are involved in the photorespiration process, primarily in C3 plants. They contain enzymes that help in the oxidation of glycolate, which is a key step in photorespiration.
Correct answer: Photorespiration6354. Cell wall shows:
- A. Complete permeability
- B. Semipermeability
- C. Differential permeability
- D. Impermeability
Explanation: The cell wall is completely permeable, allowing most substances to pass freely in and out of the cell. Its primary function is structural support, not regulation of substance passage.
Correct answer: Complete permeability6355. Keeping in view the 'fluid mosaic model' for the structure of cell membrane, which one of the following statements is correct with respect to the movements of lipids and proteins from one lipid monolayer to the other (described as flipflop movement)?
- A. While proteins can flip-flop, lipids cannot
- B. Neither lipids, nor proteins can flip-flop
- C. Both lipids and proteins can flip-flop
- D. While lipids can rarely flip-flop, proteins cannot
Explanation: Lipids can flip-flop, they do so slowly with the help of protein called Flippases. But protein do not flip-flop.
Correct answer: While lipids can rarely flip-flop, proteins cannot6356. Biological organization starts at the:
- A. Cellular level
- B. Organismic level
- C. Atomic level
- D. Submicroscopic molecular level
Explanation: The cellular level is where biological organization begins because cells are the basic units of life. They have the ability to perform all necessary life functions, making them the starting point for higher structures like tissues and organs.
Correct answer: Cellular level6357. Which of the following statements regarding mitochondrial membrane is not correct ?
- A. The outer membrane resembles a sieve.
- B. The outer membrane is permeable to all kinds of molecules.
- C. The enzymes of the electron transfer chain are embedded in the outer membrane.
- D. The inner membrane is highly convoluted forming a series of infoldings.
Explanation: The enzymes of the electron transfer chain are not embedded in the outer membrane. They are present in inner membrane.
Correct answer: The enzymes of the electron transfer chain are embedded in the outer membrane.6358. Which of the following statements regarding cilia is NOT correct?
- A. Cilia contain an outer ring of nine doublet microtubules surrounding two singlet microtubules
- B. The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane
- C. Cilia are hair-like cellular appendages
- D. Microtubules of cilia are composed of tubulin
Explanation: Option B is incorrect because the organized beating of cilia is not controlled by fluxes of Ca but by the sliding of microtubule doublets.
Correct answer: The organized beating of cilia is controlled by fluxes of Ca2+ across the membrane6359. A major breakthrough in the studies of cells came with the development of the electron microscope. This is because:
- A. The electron microscope is more powerful than the light microscope as it uses a beam of electrons which has wavelength much longer than that of photons
- B. The resolving power of the electron microscope is much higher than that of the light microscope
- C. The resolving power of the electron microscope is 200-350 nm as compared to 0.1-0.2 nm for the light microscope
- D. The electron beam can pass through thick materials, whereas light microscopy requires thin sections
Explanation: The major breakthrough with the development of the electron microscope is its significantly higher resolving power compared to the light microscope. This allows scientists to study cellular structures and organelles in greater detail.
Correct answer: The resolving power of the electron microscope is much higher than that of the light microscope6360. A student wishes to study the cell structure under a light microscope having 10X eyepiece and 45X objective. He should illuminate the object by which one of the following colours of light so as to get the best possible resolution?
- A. Blue
- B. Green
- C. Yellow
- D. Red
Explanation: Blue light has a short wavelength, which enhances the resolution of the light microscope, making it the optimal choice for studying cell structures.
Correct answer: Blue