Exam 4 (10)

Question 1

Neuronal Mechanism of Muscular Junction (3 Steps)

Answer 1

1. Neurotransmitter Uptake occurs via proton gradient + antiporter protein
2. Vesicle of neurotransmitters docks at membrane using SNARE
3. Action potential is established across said membrane dock –> Ca2+ into neuron –> leads to exocytosis

Question 2

Muscle Cell Structure Hierarchy

Answer 2

Multinuclei Muscle Cells; Myofibrils (Sarcomeres: Thin and Thick (does the contractions)); Syncytia; Myoblasts

Question 3

Important Players of Muscle Cells

Answer 3

(i) Nebulin: stabilizes by wrapping around the entire length of the filament
(ii) Titin: across entire filament – spring-like, keeps everything centered during contraction/expansion
(iii) Leiomodins: creates actin for muscle cells

Question 4

Contraction-Sliding Filament Model

Answer 4

ATP Hydrolysis at Myosin II with Ca2+ release from sarcoplasmic reticulum and transverse tubules to induce conformational change in troponin that moves tropomyosin to allow Myosin II to bind and contract