Cell Structure MCQs for NEET — Zoology Questions with Answers

A polysome, or polyribosome, is a cluster of ribosomes bound to an mRNA molecule. This structure allows for the simultaneous translation of a single mRNA by multiple ribosomes, enhancing protein synthesis efficiency.

F-particles, also known as ATP synthase particles, are located on the cristae of mitochondria. These enzyme complexes are crucial for ATP production during oxidative phosphorylation.

Microfilaments are primarily composed of actin, which is a type of protein. Actin filaments are part of the cytoskeleton and play a key role in maintaining the cell's shape, enabling cellular movements, and participating in various cellular processes.

The centriole is the organelle that directs the formation of the bipolar spindle during cell division. Centrioles are cylindrical structures that help in the organization of microtubules in the spindle apparatus, which is essential for the segregation of chromosomes during mitosis and meiosis.

Red Blood Cells (RBCs) in humans lack a nucleus. During their maturation, RBCs lose their nucleus to provide more space for hemoglobin, which allows them to efficiently transport oxygen throughout the body.

The kinetochore is a protein structure on the centromere that serves as the attachment point for spindle fibers during cell division. It is disc-shaped and plays a critical role in the proper segregation of chromosomes. The centromere itself holds the sister chromatids together.

Bacteria often contain small, circular DNA molecules known as plasmids, which are separate from the main bacterial chromosome. Plasmids can replicate independently and often carry genes that confer advantageous traits, such as antibiotic resistance.

The cell wall of fungi is primarily composed of chitin. Chitin is a long-chain polymer of N-acetylglucosamine, a derivative of glucose, and it provides structural strength to the cell wall. Unlike plant cell walls, which are made of cellulose, fungal cell walls do not contain cellulose but instead rely on chitin.

Chloroplasts are not considered a part of the endomembrane system. The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles. Chloroplasts are involved in photosynthesis and are a type of plastid, which is an organelle found only in plant cells and some protists. They have their own DNA and are thought to have originated from endosymbiotic cyanobacteria.

Paramecium is a unicellular organism that possesses cilia. Cilia are hair-like structures that cover the surface of Paramecium and are used for movement and feeding. They beat in coordinated waves, allowing the organism to move through water efficiently.