All Free Biology MCQs with Answers

• A. Lysosome
• B. Peroxisome
• C. Glyoxysome
• D. Mesosome

Explanation: Lysosomes are involved in a process called autophagy (self-eating). During this process, some old, worn-out parts of the cell, such as old mitochondria, are digested. In this way, the materials of the cell may be recycled, and the cell may be renewed.

• A. Lysosomes
• B. Autophagosomes
• C. Heterophagosomes
• D. Peroxisomes

Explanation: Lysosomes associated with self-eating (autophagy) are called autophagosomes.

• A. Lysosome
• B. Transport vesicle of endoplasmic reticulum
• C. Golgi vesicle
• D. Autophagosome

Explanation: Pathogens often hijack endocytic pathways such as pinocytosis in order to gain entry into the cell. The lysosome prevents easy entry into the cell by hydrolyzing the biomolecules of pathogens necessary for their replication strategies. Reduced lysosomal activity is an increase in viral infectivity.

• A. Cytoskeleton
• B. Exoskeleton
• C. Endoskeleton
• D. Cartilage

Explanation: Actin, myosin, tropomyosin, and other proteins that are part of muscles are also part of the cytoskeleton.

• A. Microtubules
• B. Cytosol
• C. Microfilaments
• D. Intermediate filaments

Explanation: Cytosol is the soluble or solution part of the cytoplasm, whereas the cytoskeleton consists of three components, i.e., microtubules, microfilaments, and intermediate filaments.

• A. Intermediate filaments
• B. Microtubules
• C. Microfilaments
• D. Cytoskeleton

Explanation: Microfilaments are associated with streaming movement or mass movement of cytoplasm, called cyclosis. Any intracellular movement of cytoplasm is carried out by the rhythmic contraction of microfilaments, and for pseudopodial movement, intracellular movement of cytoplasm is required.

• A. Microfilaments
• B. Cell membrane
• C. Intermediate filaments
• D. Cell wall

Explanation: Intermediate filaments are aggregated on the inner surface of the cell membrane and in the space between the cell membrane and the nucleus and provide support to the cell membrane to maintain its shape and the inner compartment of the cell.

• A. Flagella
• B. Lack of ribosomes
• C. Lack of nucleus
• D. Cytoplasm

Explanation: The distinguishing features of prokaryotic cells is that they lack nucleus and membrane-bound organelles. All prokaryotic organisms are unicellular, made of only one cell.

• A. Nucleolus
• B. Mitochondria
• C. Golgi apparatus
• D. Endoplasmic reticulum

Explanation: The most important function of the Golgi apparatus is the modification of proteins and lipids. Lipids and proteins synthesized by ER are further modified by the Golgi apparatus into glycolipids and glycoproteins, respectively.

• A. Nucleus & mitochondria
• B. Golgi & ER
• C. Chloroplast & mitochondria
• D. Cilia

Explanation: The eukaryotic cell might have evolved when a large anaerobic (living without oxygen) amoeboid prokaryote ingested small aerobic (living with oxygen) bacteria and stabilized them instead of digesting them. This idea is known as the endosymbiont hypothesis. According to this hypothesis, the aerobic bacteria developed into mitochondria, which are the sites of aerobic respiration. Ingestion of prokaryotes that resembled present-day cyanobacteria could have led to the endosymbiotic development of chloroplasts in plants.