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Flashcards in Muscles Deck (30):
1

Thick filament

Myosin

2

Thin filament

Actin

3

Largest protein known

Titin

4

Arrangements thick and thin filaments

Hexagonal arrangement: each thick filament has 6 thin filaments surrounding it. 6:3 ratio of thin : thick filaments

5

What links actin to Z-lines?

α-actin

6

What genes code for α-actin?

ACTN 1/2/3/4

7

What proteins aid in filament formation and muscle stability?

Actin capping proteins

8

Describe the structure of actin capping proteins?

Heterdimeric complex with α/β subunits

9

Genes that code for actin capping proteins

CAPZA 1/2/3

10

What is the main protein associated with the M line?

Myomesin

11

What genes express myomesin?

MYOM 1/2/3

12

Components of myosin

6 subunits, 2 heavy chains, 2 light chains

13

What digestion sites signify the point of hing in converting ATP hydrolysis into contraction/relaxation?

Trypsin and papain

14

What protein covers the myosin binding site on actin?

Tropomyosin

15

Which protein of troponin bind to Ca/regulates ca dependent muscle contraction?

TropC

16

What protein complex removes the "cover" from the myosin-binding sites of 7 G-actins?

Troponin

17

What are the types of actin?

α, β, ɣ

18

Which actin gene is primarily expressed in skeletal muscle?

ACTA 1

19

Which actin gene is primarily expressed in smooth muscle?

ACTA 2

20

Which actin gene is primarily expressed in cardiac muscle?

ACTC 1

21

Mutations in which genes cause inherited cardiomyopathy?

Troponin I and T

22

Dystrophin-glycoprotein complex

Multi-subunit complex that mediates interactions between cytoskeleton, membrane, and ECM.

23

What gene codes for DGC?

DMD gene on Chromosome X

24

Duchenne muscular dystrophy

X-linked recessive. Primarily expressed in males. S&s appear around 6months or at birth. Wheel chair dependance by 10-12 y/o/ Progressive muscle degeneration/weakness. Life expectancy 25y/o

25

Signs of Duchenne MD

Sway back, child walking on toes, poor balance, thin/weak thighs, belly sticks out, knees may bend back to take weight, difficultly swallowing

26

DMD Pathophysiology

DGC is ineffective. Have an abnormally influx of Ca that leads to cell necrosis

27

Becker Muscular Dystrophy

Milder form of MD. Non-lethal disorder. Muscle weakness is very gradual. Caused by CTG trinucleotide repeat on chromosome 19.

28

Signs of Becker MD

Sustained involuntary contractions, difficultly releasing grip when shaking hands, prominent forehead, narrow face, difficultly swallowing

29

X-linked dilated cardiomyopathy

Cardiac muscle is unable to produce dystrophin due to mutation but skeletal muscle maintains DGC synthesis

30

3 forms of energy metabolism in muscle

Creatine phosphate, glycolysis, oxidative phosphorylation