All Free Biology MCQs with Answers

• A. Activity site
• B. Storehouse
• C. Wastes
• D. None of these

Explanation: The Answer is B "storehouse". Cytoplasm stores most of the chemical content in cells. It also contains all the organelles like vacuoles, Golgi apparatus etc. It stores chemicals that are vital to plants for life and provides metabolic reactions such as the synthesis of proteins and glycolysis.

• A. Nucleus only
• B. Nucleolus only
• C. Nucleus and nucleolus only
• D. None of the above

Explanation: Molecules of rRNA are synthesized in a specialized region of the cell "nucleus" called the "nucleolus", which appears as a dense area within the "nucleus" and contains the genes that encode rRNA.

• A. Sclerenchyma
• B. Cholenchyma
• C. Mesoderm
• D. Mesenchyme

Explanation: "Mesenchymal" stem cells are adult stem cells isolated from different sources that can differentiate into other types of cells. In humans, these sources include; bone marrow, adipose tissue, umbilical cord tissue or amniotic fluid. They are non-cellular in most cases.

• A. Active diffusion
• B. Facilitated diffusion
• C. Passive diffusion
• D. Random diffusion

Explanation: Passive diffusion, also known as simple diffusion, is a process by which molecules move across a membrane from an area of higher concentration to an area of lower concentration. This process is responsible for the movement of oxygen and carbon dioxide across the Plasma membrane.

• A. Increase in saturated fatty acids in the membrane
• B. Increase in glycolipid content in the membrane
• C. Increase in phospholipid content in the membrane
• D. Increase in unsaturated fatty acids in the membrane

Explanation: The absence of double bonds decreases fluidity, making the membrane very strong and stacked tightly. Unsaturated fatty acids have at least one double bond and they increase the fluidity of the plasma membrane.

• A. Biconcave
• B. Convex
• C. Spherical
• D. Concave

Explanation: Option A: A biconcave shape refers to a structure that is concave on both sides, resembling a hollowed-out disk or lens. This shape is not typically associated with the maturing phase of the Golgi apparatus.Option B: Convex shape refers to a structure that is curved outward, resembling a bulge or a dome. This shape is also not characteristic of the maturing phase of the Golgi apparatus. Option C: A spherical shape refers to a structure that is perfectly round and symmetrical, resembling a ball or a sphere. The Golgi apparatus does not have a spherical shape during its maturing phase. Instead, it consists of stacked, curved cisternae.Option D: A concave shape refers to a structure that is curved inward, with a surface that is depressed or hollowed out. This shape is associated with the maturing phase of the Golgi apparatus. The cisternae within the Golgi stack are curved and form a concave shape as proteins and lipids move through the organelle.

• A. All sorts of vesicle formation stops
• B. All sorts of protein synthesis stops
• C. All sorts of fat synthesis stops
• D. All sorts of enzyme synthesis stops

Explanation: The Golgi apparatus is involved in the formation of various types of vesicles, including transport vesicles that carry proteins, lipids, and other molecules to their intended destinations within the cell or for secretion outside the cell. Without the Golgi apparatus, vesicle formation would be severely impaired.

• A. Chloroplast
• B. Leucoplast
• C. Protoplast
• D. Chromoplast

Explanation: The protoplast refers to the living part of a plant cell, which includes the cytoplasm, nucleus, and other organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. It does not include the cell wall or any plastids. When a plant cell is treated with cellulase and pectinase enzymes, these enzymes break down the cell wall, releasing the protoplast.

• A. Ribosomes
• B. Mitochondria
• C. Lysosomes
• D. Cystoliths

Explanation: Cystoliths are non-protoplasmic cell inclusions found in certain plant cells. They are calcareous bodies composed of calcium carbonate. Cystoliths are not considered to be part of the protoplasm but rather are found in the extracellular space within specific plant tissues, such as leaves and stems.

• A. One which helps in assembly of spindles during mitosis
• B. One involved in internal cell motion
• C. One involved in maintenance of cell shape
• D. Both a and c

Explanation: The cytoskeletal fibre that contains tubulin protein is the one that helps in the assembling of spindle fibres during mitosis. One very important function of microtubules is their role in the assembling and disassembling of the spindle structure during mitosis.