Tag: single membrane bound organelles

• Axoneme with 9+2 microtubular arrangement occurs in both cilia and flagella.
  
• Cilia and flagella are cellular projections which are covered by an extension of the plasma membrane. 
  
• They both have similar internal structures and are made up of microtubules.
• The microtubule arrangement within cilia and flagella is 9 + 2 arrangement of microtubules.
• It contains nine fused pairs of microtubules on the outer side of a cylinder and the two unfused microtubules at the centre.
• So, the correct answer is 'Both A and B'.

Tubulin belongs to the protein superfamily of globular proteins.Alpha and beta tubulins polymerize into microtubules. Microtubules function in many processes like structural support, intracellular transport, and DNA segregation. Microtubules emerge from microtubule organizing center in eukaryotic cells.

• Cilia can be defined as the tiny hair-like projections on the surface of the cell.
• These hair-like projections help in sweeping mucus, trapped dust and bacteria in the respiratory tracts.
  
• It beats asymmetrically by the sweeping action
• The asymmetrical beating pattern consists of two strokes- effective stroke and recovery stroke.
• In an effective stroke, the cilia are straight and generate flow in the same direction as its motion.
• Whereas, in recovery stroke, the cilia bend parallel to the surface and creates relatively weaker backward flow.
• So, the correct answer is 'Asymmetrically by sweeping action'.

Dynein is a family of cytoskeletal motor proteins that move along microtubules in cells. They convert the chemical energy stored in ATP to mechnical work, and hence are involved in movement of cilia and flagella.

Bacterial flagella are helically shaped structures containing the protein flagellin. The base of the flagellum (the hook) near the cell surface is attached to the basal body enclosed in the cell envelope. The flagellum rotates in a clockwise or counterclockwise direction, in a motion similar to that of a propeller. This movement is regultaed by plasma membrane.

Flagella are long, numerous hairlike projections from the plasma membrane. Flagella are longer and less in number than cilia. In multicellular organisms, cilia and flagella are the major means of locomotion in prokaryotic cells, both cilia and flagella are composed of microtubles.