All Free Biology MCQs with Answers
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19844 questions · page 630 of 1985
6291. Growth and development of plant cells is the role of:
- A. Parenchymatous cells
- B. Chlorenchymatous cells
- C. Meristematic cells
- D. Sclerenchymatous cells
Explanation: The growth and development of plant cells are primarily the role of meristematic cells. Meristematic cells are a group of undifferentiated, actively dividing cells found in specific regions of plant tissues called meristems.
Correct answer: Meristematic cells6292. Which statement describes an incorrect difference between a plant cell and a bacterial cell?
- A. Bacterial cell has 70S ribosomes whereas a plant cell has 80S ribosomes
- B. Bacterial cell divides by binary fission whereas a plant cell divides by mitosis
- C. Bacterial cells do not have a nuclear membrane whereas plant cells do
- D. None of these options are correct
Explanation: The statement "Bacterial cell has 70S ribosomes whereas a plant cell has 80S ribosomes" is true. Bacterial cells typically have 70S ribosomes, which are smaller and less complex than the 80S ribosomes found in eukaryotic cells like plant cells. The statement "Bacterial cell divides by binary fission whereas a plant cell divides by mitosis" is also true. Bacterial cells reproduce through binary fission, a process where the cell divides into two identical daughter cells. On the other hand, plant cells and other eukaryotic cells divide through mitosis, a more complex process involving the division and distribution of genetic material into two daughter cells. The statement "Bacterial cells do not have a nuclear membrane whereas plant cells do" is true as well. Bacterial cells are prokaryotic, meaning they lack a true nucleus and other membrane-bound organelles. Plant cells, being eukaryotic, do have a distinct nucleus enclosed within a nuclear membrane. So, none of the given statements describes an incorrect difference between a plant cell and a bacterial cell.
Correct answer: None of these options are correct6293. What is not true about liposomes?
- A. They are lipid vesicles with their polar heads of phospholipids on the inner and hydrophobic tails on the outer side
- B. They are bilayered spherical bodies
- C. They can easily cross the lipid bilayer
- D. They can be used in drug delivery system
Explanation: The heads (the phospho part) are polar while the tails (the lipid part) are non-polar. The heads, which form the outer and inner linings, are "hydrophilic" (water loving) while the tails that face the interior of the cell membrane are "hydrophobic" (water fearing).
Correct answer: They are lipid vesicles with their polar heads of phospholipids on the inner and hydrophobic tails on the outer side6294. The function of the cytoskeleton in a cell is:
- A. Control of the cell exchange with the outer environment
- B. Meiosis and mitosis
- C. Production of protein
- D. Mechanical support, cell motility and structure maintenance
Explanation: The cytoskeleton is involved in modulating the shape and structure of the cell, providing mechanical support and integrity, and enabling the movement of the cell.
Correct answer: Mechanical support, cell motility and structure maintenance6295. The endoplasmic reticulum contains a system of flattened membrane-bounded sacs which are named as
- A. Cristae
- B. Marks
- C. Cisternae
- D. Tubules
Explanation: Cisternae are the membrane-bound sacs that make up the endoplasmic reticulum and the Golgi body.
Correct answer: Cisternae6296. Ribosomes exist in two forms, either attached with RER or freely dispersed in the:
- A. Tonoplast
- B. Golgi bodies
- C. Cytoplasm
- D. SER
Explanation: Ribosomes exist in either the rough endoplasmic reticulum or in the cytoplasm,and their main function is to synthesize proteins.
Correct answer: Cytoplasm6297. In prokaryotic cell wall, strengthening material is:
- A. Cellulose
- B. Silica
- C. Chitin
- D. Peptidoglycan
Explanation: The prokaryotic cell wall is made up of peptidoglycan.
Correct answer: Peptidoglycan6298. Peptidoglycan or murein is a special or distinctive feature of the cell wall in:
- A. Algae
- B. fungi
- C. Bacteria
- D. Plants
Explanation: The peptidoglycan (murein) sacculus is a unique and essential structural element in the cell wall of most bacteria. Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that form a mesh-like peptidoglycan layer outside the plasma membrane, the rigid cell wall characteristic of most bacteria.
Correct answer: Bacteria6299. _is a process by which the cell takes in fluids along with dissolved small molecules. In this process, the cell membrane folds and creates small pockets and captures the cellular fluid and dissolved substances.
- A. Pinocytosis
- B. Phagocytosis
- C. Transcytosis
- D. Active Transport
Explanation: Pinocytosis is the cellular process by which a cell takes in fluids along with dissolved small molecules. It involves the folding of the cell membrane to form small pockets or vesicles. Unlike phagocytosis, pinocytosis is a passive process that does not require energy expenditure by the cell. Transcytosis involves transporting molecules across a cell, while active transport requires energy to move molecules against their concentration gradient.
Correct answer: Pinocytosis6300. The process by which unwanted structures within the cell are engulfed and digested within the lysosome is known as:
- A. Endocytosis
- B. Exocytosis
- C. Hydrolysis
- D. Autophagy
Explanation: Autophagy is a type of endocytosis that involves the engulfment and digestion of damaged or unnecessary cell parts by the cell itself. This process is essential for maintaining cell health and survival
Correct answer: Autophagy