All Free Biology MCQs with Answers

• A. Ribosomes
• B. Chloroplast
• C. Mitochondria
• D. Endoplasmic Reticulum

Explanation: It is known that the Endoplasmic reticulum acts as a reservoir for Ca2+ in cells as in contractile cells. Since Ca2+ plays an important role in fertilization therefore many Ca2+ in the form of the Endoplasmic reticulum should be present.

• A. Bacteria
• B. Fungi
• C. Algae
• D. Viruses

Explanation: Viruses are not true cells. They lack the most important part of the cell, the protoplasm. Hence, the cell theory is not applicable to viruses.

• A. Process in which samples are spun at high speed
• B. Efficient process of fabrication
• C. Slow but excellent process
• D. None of these

Explanation: Centrifugation is a method of separating molecules having different densities by spinning them in solution around an axis at high speed. Hence option A is correct.

• A. Chloroplasts
• B. Chromoplasts
• C. Leucoplasts
• D. All of them

Explanation: Leucoplasts are colourless plastids and they are found in the non-photosynthetic parts of the plant such as roots, seeds, bulbs, etc. They store starch, lipids and proteins.

• A. 70S
• B. 50S
• C. 60S
• D. 40S

Explanation: Prokaryotes contain 70S ribosomes, which themselves comprise of two further subunits; a larger 50S subunit and a smaller 30S subunit. 80S ribosomes are present in eukaryotes.

• A. Sphaerosome
• B. Peroxisome
• C. Lomasome
• D. Golgi body

Explanation: 'Lomasomes' are present outside the plasma membrane but inside the cell wall. They are membranous structures, often containing internal membranes, located between the plasma membrane and cell wall of plant cells. Lomasomes appear to be accumulations of ejected material, between the plasmalemma and cell wall that has become sequestered by the deposition of wall material. Thus, the correct answer is option 'C'.

• A. 10x
• B. 20x
• C. 50x
• D. 100x

Explanation: The 'compound microscope' is the instrument used to magnify the image of the object that we cannot see by naked eyes. It uses two lenses or lens systems, one is the 'objective lens' which enlarged the image of the object and the second is an 'ocular lens' which magnifies the image formed by the first. The total magnification is the product of the magnifications of two lens systems. Hence, the microscope which has a 10X objective lens and 10X ocular lens, it would magnify the object by 10 × 10 = '100 times'.

• A. Conducting cell
• B. Pericycle cell
• C. Photosynthetic cell
• D. All of these

Explanation: Chloroplasts are organelles found in photosynthetic cells, where they are responsible for carrying out photosynthesis, the process by which light energy is converted into chemical energy in the form of glucose. Therefore, studying chloroplasts requires the use of cells that are actively involved in photosynthesis and contain high numbers of chloroplasts.

• A. Lipid metabolism
• B. Protein metabolism
• C. Glucose metabolism
• D. Calcium metabolism

Explanation: The smooth endoplasmic reticulum helps in the metabolism of many different types of molecules, especially lipids. Therefore, it is abundant in lipid-metabolizing cells.

• A. Hydrophobic
• B. Hydrophilic
• C. Neutral
• D. Both Options A and B are correct

Explanation: The plasma membrane consists of a lipid bilayer associated with proteins. The polar phospholipid heads are hydrophilic and are directed outward, while the non-polar tails are hydrophobic and are directed inward, facing each other. Therefore, the hydrophilic ends are in contact with both the external extracellular environment and the internal environment of the cell.