Muscle (Biochemistry) Flashcards
1
Q
M line components
A
myomesin & M-protein
2
Q
Z line components
A
α-actinin
3
Q
myosin components
A
- consists of 2 large heavy chains & 4 small light chains
4
Q
light meromyosin
A
forms myosin filaments
5
Q
heavy meromyosin
A
- forms cross bridges
- S1 hydrolyses ATP binds to actin
6
Q
2 components of actin
A
- g-actin
- f-actin
7
Q
g-actin
A
- globular
- forms actin filament
8
Q
f-actin
A
- intertwine/form the trunk for tropomyosin & troponin to attach
- greatly increases ATPase activity of myosin
9
Q
muscle contraction is controlled by…
A
sliding filaments
10
Q
Isoforms
A
- variations in proteins that can arise from 1 gene
- due to splicing / post transcriptional modification of RNA
11
Q
myosin can have multiple isoforms that influence…
A
- muscle
- exercise
-performance
12
Q
types of myosin in adult humans
A
- myosin heavy chain (MHC)
- Type I
- Type IIa
- Type IIx
13
Q
how does Ca2+ control muscle activity?
A
binds to troponin to uncover tropomyosin from actin (allowing cross bridges to form)
14
Q
subunits of troponin
A
Tnl = binds to actin
TnC = binds Ca2+
TnT = bnds tropomyosin
15
Q
What happens when there is no ATP in muscle?
A
- Rigor Mortis = when muscles harden due to the lack of ATP in muscle
- ATP is required for both contraction & relaxation
