Structure Of Sliding Filament Flashcards
What is sacromere, sacromella, sacroplasm, sacroplasmiz reticulum, Myofribril
- Basic functional unit of a fibre
- plasma membrane wrapped around the fibres
- cytoplasm within the fibres
- endoplasmic reticulum within the sacromere
- long cylindrical organelles in sacromeres that bring about muscle contraction - made of actin and myosin
What is the z line
Separates the sacromeres
Which one is actin which one is myosin
Actin is the much more thin on the outside whereas the myosin is the thick inner part. Under a microscope there are also light bands and dark bands. Dark bands is where the myosin chunks overlap with the actin layers and the light bands is where it is just actin layers.
What is the H zone
The area which only the myosin is present
What happens to the bands in muscle contraction
Dark bands stay exactly same length, but light bands shorten a lot, that brings about muscle contraction.
What is structure of actin
But fr the actin is surrounded by a protein called tropomyosin and it is held in place by a troponin which can bind to calcium ions that can lead to a conformational change (the movement of the tropomyosin). The tropomyosin also wraps around the dents of the actin and these are called Actin Myosin binding sites
What is the structure of myosin
Much thicker than actin and has extensions called myosin filaments. The end of the myosin filaments is called the myosin head and on the end of the heads is ADP. This will be released and replaced by ATP is myosin moves. The myosin head also has an ATPase component which can hydrolyse ATP - ADP + Pi. It can also form cross bridges with actin at AM binding site
