All Free Biology MCQs with Answers
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19844 questions · page 659 of 1985
6581. The chemical compound has the same percentage in the bacterial as well as the mammalian cell:
- A. Carbohydrates
- B. Protein
- C. Lipid
- D. Water
Explanation: The percentage of water in both bacterial and mammalian cell is 70%.Hence, this option is correct.
Correct answer: Water6582. Which one is the powerhouse of the cell?
- A. Ribosomes
- B. Golgi Apparatus
- C. Mitochondria
- D. Chloroplasts
Explanation: On the cristae of mitochondria are located enzymes and coenzymes by means of which carbohydrates (starch), fatty acids (lipids), and amino acids (lipids) are metabolized to CO₂ and H₂O. Energy in the form of ATP is released in this process, which is stored within mitochondria. ATP is an energy-rich compound, and it provides energy for various cellular activities. Hence, "mitochondria" is known as the "powerhouse" of the cell. Hence, this option is correct.
Correct answer: Mitochondria6583. Which of the following best describes the plasma membrane?
- A. Adhesible
- B. Permeable
- C. Impermeable
- D. Semipermeable
Explanation: The plasma membrane performs several functions but the main and the most important functions are protection of cell cytoplasm to regulate the flow of solutions and material in an out of the cell with certain limitation. These limitations or checkin lowacross the membrane is called differential or selective permeability. Therefore, plasma membrane is called semipermeable membrane.
Correct answer: Semipermeable6584. Protein layers are embedded in lipid bilayers; this was explained by
- A. Lock and key Model
- B. Induced fit model
- C. Fluid mosaic model
- D. Sandwich model
Explanation: Fluid mosaic model: According to the fluid mosaic model, the lipid bilayer is retained as the core of the membrane. The structure and arrangement of membrane proteins in the fluid-mosaic model are like icebergs in the sea. The proteins occur as a 'mosaic' of discontinuous particles that penetrate deeply into and even completely through the lipid sheet. Hence, this option is correct.
Correct answer: Fluid mosaic model6585. Just given function is associated with lysosomes:
- A. Protein synthesis
- B. Processing & packaging
- C. Intracellular digestion
- D. Lipid synthesis
Explanation: Lysosomes contain enzymes that break down cellular waste, damaged organelles, and macromolecules. This makes them the main organelles responsible for intracellular digestion.
Correct answer: Intracellular digestion6586. Which of the following organelle is responsible for the production of steroid hormones?
- A. Mitochondria
- B. Golgi bodies
- C. Smooth endoplasmic reticulum
- D. Rough endoplasmic reticulum
Explanation: Mitochondria are responsible for fatty acid metabolism while steroid biosynthesis takes place in SER.
Correct answer: Smooth endoplasmic reticulum6587. Which of the following organelle is most abundant in those animal com cells which exhibit phagocytic activity?
- A. Glyoxysomes
- B. Microbodies
- C. Lysosomes
- D. Peroxisomes
Explanation: Lysosomes are most abundant in those cells which are specialized for phagocytic activities, for example WBCs
Correct answer: Lysosomes6588. Interior of chloroplast is divided into heterogeneous structure, embedded in the matrix known as:
- A. Grana
- B. Stroma
- C. Thylakoids
- D. Cisternae
Explanation: Thylakoids are flattened vesicles which arrange themselves in the form of grana and inter-granum. Grana are piled up in the form of coins. They are present in matrix known as stroma.
Correct answer: Grana6589. Plasma membrane is chemically composed of:
- A. Phospholipids only
- B. Lipids and proteins
- C. Lipids and carbohydrates
- D. Glycoproteins
Explanation: Plasma membrane is made up 60-80 % of proteins, 20-40 % of lipids and very small amounts of carbohydrates.
Correct answer: Lipids and proteins6590. Endoplasmic reticulum contains a system of flattened membrane-bounded sacs which are named as:
- A. Cristae
- B. Marks
- C. Cisternae
- D. Tubules
Explanation: Material in Endoplasmic reticulum is separated from the cytoplasmic materials by the spherical or tubular membranes, called cisternae.
Correct answer: Cisternae