Question

Exposing skeletal muscle fibers to ________ removes ions and ATP from the cells and disrupts the troponin-tropomyosin complex such that it can no longer block the active sites on the actin molecules.

Answer 1

Answer:

Glycerine/Glycerin

Explanation:

This is a colourless ,odourless syrup liquid which is sweet to taste .it is non toxic,it is also refers to as glycerol.Its medicinal uses includes anti bacteria and anti viral for wound treatments,and as a marker in liver diseases.

Chemically it contains three hydroxyl (OH) group bonded together.This structure is an adaptation for dissociation in water and also accounts for its hygroscopic nature.

When a muscle fibre is exposed to Glycerine,these cells contracts,reducing the space among the cells.Hence the fibres contraction is affected,follow by  reduction in length.

Basically, during glycerine is applied to muscle cells,this substance punctures the sacolemma, creating holes.The latter aid the diffusion of ca+ and ATPs across this membrane in the muscle cells.

Generally the ca+ from the Sacroplasmic reticulum binds with the troponin,leading to the change in  its shape to bind with the actin filament.Protein tropomyosin  also binds with the actin filaments on different positions. Thus these proteins forms the troponin-tropomyosin complex on the filament.The proteins exposes  part  of the actin molecules, as  the binding site for the myosin  head cross bridges between the two filaments types.

Hydrolysis of ATP supplies energy for the withdrawal of the myosin head from the actin filaments and its  tilts back to the filaments to ensure contraction  and relaxation of muscles muscles fibres.

Now.if glycerine created holes in the sacrolemma,Ca+ ions will be reduced,ATPs molecules hydrolysis  will  be also be affected,therefore, troponin-tropomyosin complex can not be formed.Thus actin filaments would not be exposed,for myosin head to bind, (therefore the myosin binding site is blocked on the actin molecules)this eventually prevent  muscles contractions without the nervous transmission.