All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19844 questions · page 612 of 1985
6111. Which of the following are colorless?
- A. Chloroplasts
- B. Chromoplasts
- C. Leucoplasts
- D. None of these
Explanation: Chloroplasts are green in colour due to the presence of green pigment " chlorophyll". Chromoplasts are colored and help for pollination and seed dispersal. Leucoplasts are colorless and are found in underground parts of the plant and store food.
Correct answer: Leucoplasts6112. Which of the following has 26 chromosomes?
- A. Corn
- B. Sugarcane
- C. Frog
- D. Mouse
Explanation: Mouse has 40, corn has 20. sugarcane has 80, and frogs have 26 chromosomes in their diploid cells.
Correct answer: Frog6113. Detoxification of harmful drugs within the cell is done by:
- A. Nucleolus
- B. Smooth endoplasmic reticulum
- C. Ribosomes
- D. Rough endoplasmic reticulum
Explanation: The detoxification of drugs is the function of SER while protein synthesis is the function of RER. Mechanical support, however, is the function of both RER and SER.
Correct answer: Smooth endoplasmic reticulum6114. A group of ribosomes attached to messenger RNA is known as:
- A. Ribosome
- B. Lysosome
- C. Nucleosome
- D. Polysome
Explanation: A group of ribosomes attached to mRNA is known as polysome.
Correct answer: Polysome6115. The entire cell wall of bacteria is often regarded as a single huge molecule or molecular complex called:
- A. Capsule
- B. Secondary wall
- C. Slime capsule
- D. Sacculus
Explanation: In case of bacterial cells, the entire cell wall is olien regarded as a single huge molecule or molecular complex known as sacculus. Capsules and smiles are outer covering the cell wall in some bacteria.
Correct answer: Sacculus6116. The inner membrane of mitochondria is folded to form finger like structure called:
- A. Cristae
- B. Vesicle
- C. Matrix
- D. Cisternae
Explanation: Cristae are folds in the inner mitochondrial membrane.
Correct answer: Cristae6117. Which of the following contains a peptidoglycan cell wall?
- A. Penicillium
- B. Bacterium
- C. Adiantum
- D. Polytrichum
Explanation: :Bacterial cell walls are made of peptidoglycan also called murein, which is made from polysaccharide chains cross-linked by short peptides. Bacterial cell walls are different from the cell walls of plants and fungi which are made of cellulose and chitin,respectively.
Correct answer: Bacterium6118. Plastids are only found in the :
- A. Animals and Plants
- B. Animals
- C. Plants
- D. Viruses
Explanation: Plastids are present in autotrophic eukaryotes and multicellular organisms such as plants and algae. Animals are heterotrophs and viruses are not considered as living organisms.
Correct answer: Plants6119. The model of plasma membrane suggests that proteins are embedded in lipid bilayer.
- A. Unit membrane
- B. Fluid mosaic
- C. Permeable
- D. Ultracentrifuge
Explanation: Fluid mosaic model of the plasma membrane described the arrangement of phospholipids two layers, stabilized interiorly by the hydrophobic interactions while hydrophilic interactions at intracellular and extracellular faces with embedded proteins randomly.
Correct answer: Fluid mosaic6120. Centriole is made up of _ microtubules.
- A. 9
- B. 27
- C. 3
- D. 12
Explanation: Most centrioles are made up of triplet of nine microtubules. Hence centrioles have (9*3) 27 microtubules.
Correct answer: 27