Question

Number of dynein arms

• A. Four attached to subfibre B
• B. Two attached to subfibre B
• C. Two attached to subfibre A
• D. Four attached to subfibre A

Answer 1

Answer: (C)

Two attached to subfibre A

• Dynein arms refer to the structures that extend clockwise from one tubule of each microtubule (nine doublets) towards the adjacent doublet in the axoneme of cilia or flagella.
  
• Each axoneme contains eight or nine dynein heavy chains.
  
• The inner and outer dynein arms are two-headed structures which contain two heavy chains each.
  
• So, the correct answer is 'Two attached to sub fibre A'.