All Free Biology MCQs with Answers
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19844 questions · page 672 of 1985
6711. Plant cells are distinguishable from animal cells in containing:
- A. Mitochondria
- B. Endoplasmic reticulum
- C. Ribosomes
- D. Cell wall
Explanation: Plants contain cell wall as outer most membrane whereas in animal cell it is absent.
Correct answer: Cell wall6712. Pick the correct one with reference to plant cell:
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Centrioles are absent in higher plant cells.
Correct answer: Option B6713. The layers of cellulosic fibers in cell wall are arranged with each other at:
- A. Obtuse angle
- B. Parallel angle
- C. Right angle
- D. Horizontal angle
Explanation: Cellulose fibers are responsible for strengthening of cell wall of plants in crisscross manner and placing these fibers at right angle with each other gives more strength.
Correct answer: Right angle6714. Which of the following is related to prokaryotic cell wall?
- A. Murein
- B. Sacculus
- C. Peptidoglycan
- D. All A, B, C
Explanation: Cell wall of prokaryotes is composed of polysaccharide chains bounded to shorter chains of amino acid fonning peptidoglycan or murein. The entire cell wall is often regarded as a single huge molecule called sacculus.
Correct answer: All A, B, C6715. It is absent in secondary cell wall.
- A. Silica
- B. Pectin
- C. Waxes
- D. Cutin
Explanation: All are present in the secondary cell wall except pectin, as it is a component of the primary cell wall.
Correct answer: Pectin6716. Which substance from the following is important for the mechanical stability of cell membranes, as without it membranes quickly break and cells burst open? The hydrophobic region of this molecules help to prevent ion or polar molecules from passing through the cell membrane?
- A. Protein
- B. Phospholipids
- C. Glycolipids
- D. Cholesterol
Explanation: Phospholipids provide mechanical support to the cell membrane and also has a hydrophobic region.
Correct answer: Phospholipids6717. Self-eating ability of lysosomes is called:
- A. Phagocytosis
- B. Autophagy
- C. Pinocytosis
- D. Exocytosis
Explanation: Autophagy is the natural, regulatory mechanism of the cell that removes unnecessary or dysfunctional components. It allows the orderly degradation and recycling of cellular components with the help of lysosomes.
Correct answer: Autophagy6718. Passive processes for the movement of molecules across cell surface membrane are:
- A. Facilitated diffusion and osmosis
- B. Diffusion and exocytosis
- C. Pinocytosis and facilitated diffusion
- D. Osmosis and phagocytosis
Explanation: Osmosis, diffusion and facilitated diffusion are passive processes of passage of molecules across the cell membrane but exocytosis and endocytosis are active processes of molecules across the cell.
Correct answer: Facilitated diffusion and osmosis6719. The fluid mosaic model of cell membrane is:
- A. Phospholipid bilayer having scattered proteins
- B. Phospholipid bilayer is enclosed in protein layer
- C. Carbohydrate chains are attached with phospholipid bilayer
- D. In which protein molecules are free to move about in a fluid bilayer of phospholipid molecules
Explanation: The model proposes that the membrane is a phospholipids bilayer in which protein molecules are either partially or wholly embedded. The proteins are scattered throughout the membrane in an irregular pattern just like large ice bergs float in the sea.
Correct answer: Phospholipid bilayer having scattered proteins6720. According to the fluid mosaic model of cell membrane, which zone is embedded inside?
- A. Hydrophobic
- B. Globular
- C. Hydrophilic
- D. Filamentous
Explanation: Hydrophobic ends face each other while hydrophilic ends are appeared on the surface.
Correct answer: Hydrophobic