All Free Biology MCQs with Answers

• A. Cristae
• B. Cisternae
• C. Matrix
• D. F1 particles

Explanation: The infoldings increase surface area for reactions to take place Cristae are the infoldings of the inner membrane of mitochondria Cisternae refers to any of the flattened discs of the endoplasmic reticulum and golgi apparatus Matrix is the space within the inner membrane F1 particles contain ATP synthase which is involved in ATP synthase

• A. Ending
• B. Forming
• C. Starting
• D. Maturing

Explanation: The Golgi complex is an organelle in the eukaryotic cell that is responsible for modifying, sorting, and packaging proteins and lipids for delivery to their final destinations. The Golgi complex has two faces, the cis face and the trans face. The inner concave surface of the Golgi complex is the trans face, which is responsible for receiving and sorting newly synthesized proteins and lipids. The outer convex surface is the cis face, which is responsible for packaging and delivering these molecules to their final destinations. The Golgi complex also has a maturing face, which is the area where the proteins and lipids undergo further processing and modification before they are packaged and transported to their final destinations.

• A. Option A
• B. Option B
• C. Option C
• D. Option D
• E. Option E

Explanation: The question asks for eukaryotic cells, which possess a nucleus as well as other membrane bound organelles such as mitochondria, lysosomes, golgi apparatus, endoplasmic reticulum in addition to (80S) ribosomes. Only option E fulfills this criteria, as all other options have one or more of the components missing.

• A. Cell wall
• B. Cell membrane
• C. Tonoplast
• D. Unit membrane
• E. Polar substances

Explanation: Option A: The outermost boundary of most leaf cells is the cell wall. It is a rigid layer that surrounds the cell membrane and provides support and protection for the cell. It is made up of cellulose, a long-chain carbohydrate. The cell wall is not present in animal cells. Option B: The cell membrane is the outermost boundary of all cells, but it is not the outermost boundary of most leaf cells. Option C: The tonoplast is the membrane that surrounds the vacuole, which is a large organelle found in plant cells. It is not the outermost boundary of the cell. Option D: A unit membrane is a single layer of phospholipids that forms the basic structure of all cell membranes. It is not the outermost boundary of any cell. Option E: Polar substances are molecules that have a positive and negative end. They are not boundaries of cells.

• A. Lysosomes
• B. Mitochondria
• C. Peroxisomes
• D. Glyoxysomes

Explanation: Option A: Lysosomes are another type of cell organelle that contains enzymes that can break down waste products and foreign invaders. However, lysosomes do not produce hydrogen peroxide. Option B: Mitochondria are the powerhouses of the cell, responsible for producing ATP, the cell's energy currency. They do not produce hydrogen peroxide. Option C: Peroxisomes are small, membrane-bound organelles that are found in most eukaryotic cells. They contain enzymes that carry out oxidation reactions, which can produce hydrogen peroxide as a byproduct. Hydrogen peroxide is a reactive molecule that can damage cells. Peroxisomes are small organelles that contain enzymes involved in various metabolic processes, including the breakdown of fatty acids and the detoxification of harmful substances. One of the enzymes present in peroxisomes is called catalase, which facilitates the breakdown of hydrogen peroxide into water and oxygen. This prevents the accumulation of hydrogen peroxide, which can be damaging to cells if it builds up in high concentrations. Option D: Glyoxysomes are a type of peroxisome that is found in plant cells. They are involved in the breakdown of fatty acids to produce carbohydrates. They do not produce hydrogen peroxide. describes organelles that contain hydrolytic enzymes that break down endocytosed foreign particles or even intracellular fragments.

• A. Store hydrolytic enzymes
• B. Perform autophagy
• C. Destruction of cell
• D. All of above

Explanation: Lysosomes store hydrolytic enzymes, which play their role in autophagy and destruction of old cells. Hence, the correct option is D.

• A. Phospholipid
• B. Carbohydrates
• C. Polysaccharide
• D. Cellulose

Explanation: The permeability of the cell membrane and its permeability depends upon the phospholipid content of that membrane. All other chemical components mentioned (carbohydrates, polysaccharides, and cellulose) are not part of the cell membrane.

• A. Secondary wall
• B. Primary wall
• C. Middle lamella
• D. Tonoplast

Explanation: The cell wall in plants and few algae consists of three important layers:The primary cell wall is the outermost thin, flexible and extensible layer.The secondary cell wall is a thick layer present inside the primary cell wall and is sandwiched between the plasmalemma and primary cell wall.The middle lamella is the first formed layer which is rich in pectins and forms plasmodesmata connections between adjacent cell walls.So, the correct answer is 'Secondary wall'.

• A. Ribosomes
• B. Matrix
• C. Porin
• D. Cristae

Explanation: Factual recall; 'Ribosomes' are organelles, that serve as sites of protein synthesis. 'Matrix' refers to the space confined by the inner mitochondrial membrane within the mitochondria. 'Porin' refers to a transport protein that enables the passive diffusion of certain molecules across a membrane. Cristea are finger-like infoldings, which are formed by the inner membrane of the mitochondria.

• A. Chloroplast
• B. Golgi body
• C. Ribosome
• D. Mitochondrion

Explanation: The 'Golgi apparatus' is a cellular organelle responsible for the modification and trafficking of proteins to other organelles such as the lysosome, the digestive organelle of the cell.