Tag: locomotion and movement

• Skeletal muscle fiber is made up of two types of filaments. They are thick filament(myosin) and thin filament(actin). 
  
• Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin.
  
• Hence Component of actin filament of a sarcomere is Actin, troponin, and tropomyosin.
• So, the correct answer is 'Actin, troponin, and tropomyosin'.

• The myofibril is composed of two types of filaments. They are thick filament(Myosin) and Thin filament(Actin).
  
• Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin. In the resting state tropomyosin partially covers myosin binding site on actin. Tropomyosin is a fibrous protein and Troponin is a globular protein.
• So, the correct answer is 'Troponin-fibrous protein'

• Myofibril is made up of two types of filaments.They are thin filament(actin) and thick filament(myosin).
  
• Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin.
  
• Each myosin (thick) filament is also a polymerized protein. Many monomeric proteins called Meromyosins, constitute one thick filament. Globular head of meromyosin consists of Heavy meromyosin (HMM).
  
• So, the correct answer is 'i, ii and iii are correct'

• The myofibril is composed of two types of filaments. They are thick filament (Myosin) and Thin filament (Actin).
  
• Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin. In the resting state tropomyosin partially covers myosin binding site on actin.
  
• Increase in Ca++ level leads to the binding of calcium with a subunit of troponin i.e troponin-C on actin filaments and thereby remove the masking of active sites for myosin. Utilizing the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
• Hence In a resting muscle fibre, tropomyosin partially covers myosin binding sites on actin.
• So, the correct answer is 'Myosin binding sites on actin'.

• Myofibril is made up of two types of filaments. They are thick filament (myosin) and thin filament (actin). Actin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively
  
• Each myosin (thick) filament is a polymerized protein. Many monomeric proteins called meromyosins constitute one thick filament.
  
• Hence myosin is the thick filament of muscle.
• So, the correct answer is 'Myosin'.

• Myofilament is the filaments of myofibrils, constructed from proteins, principally myosin or actin.
  
• They are made up of thick and thin myofilament, which helps to give it a striped appearance.

Skeletal muscle is composed of muscle fibres which have smaller units called myofibrils. There are three types of proteins make up each myofibril; they are contractile, regulatory and structural proteins. By contractile proteins, we mean actin (thin filament), a globular protein assembling with a long beady structure consisting chains and myosin (thick filament).

Skeletal muscle is composed of muscle fibres which have smaller units called myofibrils. There are three types of proteins make up each myofibril; they are contractile, regulatory and structural proteins. By contractile proteins, we mean actin (thin filament) and myosin (thick filament).