All Free Biology MCQs with Answers

• A. Golgi apparatus
• B. Lysosome
• C. Mitochondrion
• D. Cell wall
• E. Ribosomes

Explanation: The cell wall is a non-living component that surrounds the cell membrane in plant cells, bacteria, fungi, and some protists. It provides structural support and protection to the cell. The cell wall is primarily composed of cellulose in plant cells, while in bacteria, it can be made up of peptidoglycan or other substances depending on the bacterial species. The cell wall is secreted and maintained by the living portion of the cell, specifically by the processes occurring within the plasma membrane and the Golgi apparatus. It plays a crucial role in maintaining cell shape, preventing excessive water uptake, and providing mechanical strength to withstand environmental pressures.

• A. AF, BG, CJ, DI, EH
• B. AH, BI, DF, CG, EJ
• C. AJ, BI, CH, DG, EF
• D. AH, BF, DG, CI, EJ

Explanation: To solve this quickly just match one or two organelles to their correct function,crossing out the wrong options while doing so. Peroxisomes carry out detoxification of alcohol which is only in option B so we can easily choose it,no other options have DF. To check others, we know that smooth ER deals with cholesterol and fats that is why E goes with J.Ribosomes carry out protein synthesis.Centrioles form astral rays.Lysosomes destroy foreign particles.Hence,AH, BI, DF, CG, EJ is correct.

• A. I only
• B. I&II
• C. II & III
• D. II & IV
• E. III & IV

Explanation: Nucleus is the control centre of the cell and stores the genetic material of the cell,so we say that statements II and IV are correct, making option D correct. Nucleus does not store wastes and other substances plus it also does not help in cellular transport system, that eliminate option A,B,C and E.

• A. Chloroplasts
• B. Chromoplasts
• C. Leucoplasts
• D. Vacuoles

Explanation: Anthocyanins are found in the cell vacuole, mostly in flowers and fruits, but also in leaves, stems, and roots

• A. Plastids
• B. Chromoplasts
• C. Leucoplasts
• D. None of the given options

Explanation: Elaioplasts found in plants are actually one of the types of leucoplasts.

• A. Amyloplast
• B. Elaioplast
• C. Proteinoplast
• D. Etioplast

Explanation: Leucoplasts are classified into three groups: amyloplasts (which store starch), elaioplasts or osteoblasts (store lipids), and proteinoplasts (store proteins).

• A. Endocytosis
• B. Exocytosis
• C. Active transport
• D. Osmosis

Explanation: 'Osmosis' is the movement of a solvent across a semipermeable membrane, toward a higher concentration of solute (lower concentration of solvent). Both 'diffusion' and 'osmosis' are passive transport processes, which means they do not require any input of extra energy to occur.

• A. It functions in joining adjacent cells together.
• B. It functions in recognizing foreign cells.
• C. It increases the rate of transport of ions across the membrane.
• D. It stabilizes the cell membrane.

Explanation: 'Cholesterol' is interspersed between the phospholipid bilayer. In case of temperature deviation, the fatty acid tails may melt or freeze. Changing the fluidity of the membrane, that is, with an increase in temperature, the phospholipid entities tend to move away from each other, and in low temperatures, the molecules will move very close to each other, disturbing the membrane's ability to transport substances. Cholesterol is the stabilizing molecule that prevents extreme movement of phospholipids during temperature fluctuation So, the correct answer is 'It stabilizes the cell membrane.'

• A. Stomach and Liver
• B. Muscle and Stomach
• C. Heart and Liver
• D. Liver and Muscle

Explanation: Tissues and organs, that need a lot of energy, have large numbers of mitochondria in their cells. For example, liver cells and muscle cells contain a lot of mitochondria. Muscle cells are associated with a large number of mitochondria as they require more ATP (energy) to function than other cells.

• A. Muscle cell
• B. Nerve cell
• C. White Blood cell
• D. Red Blood cell

Explanation: Unlike most other eukaryotic cells, mature red blood cells don't have nuclei. When they enter the bloodstream for the first time, they eject their nuclei and organelles so, they can carry more hemoglobin, and thus, more oxygen. Each red blood cell has a lifespan of around 100-120 days.