Muscles

Question 1

Thick filament

Answer 1

Myosin

Question 2

Thin filament

Answer 2

Actin

Question 3

Largest protein known

Answer 3

Titin

Question 4

Arrangements thick and thin filaments

Answer 4

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

Question 5

What links actin to Z-lines?

Answer 5

α-actin

Question 6

What genes code for α-actin?

Answer 6

ACTN 1/2/3/4

Question 7

What proteins aid in filament formation and muscle stability?

Answer 7

Actin capping proteins

Question 8

Describe the structure of actin capping proteins?

Answer 8

Heterdimeric complex with α/β subunits

Question 9

Genes that code for actin capping proteins

Answer 9

CAPZA 1/2/3

Question 10

What is the main protein associated with the M line?

Answer 10

Myomesin

Question 11

What genes express myomesin?

Answer 11

MYOM 1/2/3

Question 12

Components of myosin

Answer 12

6 subunits, 2 heavy chains, 2 light chains

Question 13

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

Answer 13

Trypsin and papain

Question 14

What protein covers the myosin binding site on actin?

Answer 14

Tropomyosin

Question 15

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

Answer 15

TropC

Question 16

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

Answer 16

Troponin

Question 17

What are the types of actin?

Answer 17

α, β, ɣ

Question 18

Which actin gene is primarily expressed in skeletal muscle?

Answer 18

ACTA 1

Question 19

Which actin gene is primarily expressed in smooth muscle?

Answer 19

ACTA 2

Question 20

Which actin gene is primarily expressed in cardiac muscle?

Answer 20

ACTC 1

Question 21

Mutations in which genes cause inherited cardiomyopathy?

Answer 21

Troponin I and T

Question 22

Dystrophin-glycoprotein complex

Answer 22

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

Question 23

What gene codes for DGC?

Answer 23

DMD gene on Chromosome X

Question 24

Duchenne muscular dystrophy

Answer 24

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

Question 25

Signs of Duchenne MD

Answer 25

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

Question 26

DMD Pathophysiology

Answer 26

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

Question 27

Becker Muscular Dystrophy

Answer 27

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

Question 28

Signs of Becker MD

Answer 28

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

Question 29

X-linked dilated cardiomyopathy

Answer 29

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

Question 30

3 forms of energy metabolism in muscle

Answer 30

Creatine phosphate, glycolysis, oxidative phosphorylation