All Free Biology MCQs with Answers

• A. Golgi apparatus
• B. Endoplasmic Reticulum
• C. Lysosomes
• D. Peroxisomes

Explanation: The correct answer is B) Endoplasmic Reticulum. The outer membrane of the nuclear envelope is continuous with the endoplasmic reticulum…

• A. RNA and protein
• B. RNA and lipids
• C. RNA and carbohydrates
• D. Proteins and carbohydrates

Explanation: Ribosomes are complex molecular machines found within all living cells that perform biological protein synthesis (translation).

• A. 250 um
• B. 50 um
• C. 750 mm
• D. 500 um

Explanation: To calculate the total magnification of an object observed under a microscope, you need to multiply the magnification of the eyepiece…

• A. Nucleus
• B. Mitochondrion
• C. Endoplasmic Reticulum
• D. Plastids
• E. Cytoskeleton

Explanation: The correct answer is the mitochondrion, as it is the site where aerobic respiration takes place, producing ATP through the citric acid…

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

Explanation: The correct answer is Heart and Muscle. Both the heart and muscle tissues require a significant amount of energy due to their continuous…

• A. Enzymes
• B. Coenzymes
• C. Ribosomes
• D. Thylakoid

Explanation: Thylakoids are specific to chloroplasts, where they facilitate photosynthesis by housing the chlorophyll and other components necessary…

• A. Oxidative phosphorylation
• B. Liver cells
• C. To maintain calcium ions
• D. All of these

Explanation: Mitochondria help in all of the given functions and are, therefore, very important organelles.

• A. It contains protein molecules embedded in lipid bilayer
• B. It is a differentially permeable membrane
• C. It contains charged pores thus ions being charged particles across cell membrane much easier than neutral particles
• D. it may get infolded to engulf solid or liquid material

Explanation: The substances which are lipid soluble cross it more easily than others, therefore, it regulates the low of materials and ions to maintain…

• A. Their physical properties like size & weight
• B. Their physical properties like density
• C. Their electrical properties like their charges
• D. Both a and b

Explanation: Cell fractionation involves two steps: homogenisation (cells are broken apart in a blender) and centrifugation (cell components are spun…

• A. Grana
• B. Stroma
• C. Thylakoid
• D. lntergrana

Explanation: Stroma is the fluid-filled space surrounding the grana inside a chloroplast.

• A. Ribosomes
• B. Cell membrane
• C. Cytoplasm
• D. Cell Wall

Explanation: The correct answer is the Cell Wall. The cell wall is a rigid layer that provides structural support and protection to plant cells and is…

• A. Integral proteins of the plasma membrane
• B. Proteins that bind to ion channels in the plasma membrane
• C. Proteins that attach to lipids of the plasma membrane using specific anchors
• D. Proteins that randomly associate with the plasma membrane

Explanation: Glycosyl phosphatidylinositol (GPI)-anchored proteins are peripheral membrane proteins that are connected to the cell membrane through a…

• A. Mitochondria and Ribosomes
• B. Mitochondria and Chloroplasts
• C. Mitochondria and Vacuoles
• D. Mitochondria and Lysosomes

Explanation: The correct answer is Option B: Mitochondria and Chloroplasts. These organelles are unique because they contain their own DNA and can…

• A. They are lipid vesicles with their polar heads of phospholipids on the inner and hydrophobic tails on the outer side
• B. They are bilayered spherical bodies
• C. They can easily cross the lipid bilayer
• D. They can be used in drug delivery systems

Explanation: Liposomes are microscopic vesicles composed of lipid bilayers. They are characterized by having polar (hydrophilic) heads facing outward…

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

Explanation: Mitochondria are one of the organelles that are bound by two membranes.

• A. Ribosome
• B. Mitochondria
• C. Nucleus
• D. Centriole

Explanation: The classic role of mitochondria is oxidative phosphorylation, which generates ATP by utilizing the energy released during the oxidation…

• A. rDNA
• B. RNA
• C. Ribosomes
• D. Chromosomes

Explanation: The nucleolus is a key subcompartment within the cell nucleus responsible for producing ribosomes.

• A. Ionic materials
• B. Polar materials
• C. Non-polar materials
• D. Glycoproteins

Explanation: The lipid bilayer of the plasma membrane is composed mainly of phospholipids, which have hydrophobic tails and hydrophilic heads.

• A. Locomotory structures
• B. Membranes connecting the nucleus with plasmalemma
• C. Connections between adjacent cells
• D. Lignified cemented layers between cells

Explanation: Plasmodesmata are microscopic channels that connect the cytoplasm of adjacent plant cells, allowing communication and transport of various…

• A. Protein synthesis
• B. Processing
• C. Intracellular digestion
• D. Lipid synthesis
• E. Carbohydrate synthesis

Explanation: Lysosomes have intracellular hydrolytic enzymes that hydrolyze the macromolecules within the vacuoles/vesicles, which carry out…