Ms lectures 5-6 Flashcards Preview

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Flashcards in Ms lectures 5-6 Deck (13):
1

The ______ is the smallest functional contractile unit in a muscle.

sarcomere

2

What is the length of the micron and how many are end to end in a myofibril?

2.7 microns in length; 10,000 sarcomeres end to end in a myofibril.

3

The two contractile proteins are...

actin and myosin

4

The two regulatory proteins...

troponin and tropomyosin

5

True or False. Tropomyosin consists of two intertwined molecules about the length of seven actin molecules.

True.

6

True or False. 300-400 globular actins in each of the two intertwined strands.

True

7

Troponin types:
Troponin A
Troponin C
Troponin T
What is the function?

Troponin A: Inhibition/resting state in which it binds to actin, and not at the myosin binding site
Troponin C: binds calcium --> conformational change in troponin that allows movement of tropomyosin
Troponin T: binds to tropomyosin.

8

The two structural proteins are...

titin and nebulin

9

A band

wide dark band of thick filaments in the middle of the sarcomere which overlap with the thin filaments

10

I band

light band which lives between the ends of the A band consist of the ends of the thin filament that does not overlap the thick filament;
basically LIGHT and ACTIN

11

Z line

bisects the I band and consists of thin filaments from two sarcomeres

12

H zone

space between the opposing ends of the two sets of thin filaments; MYOSIN only.

13

M line

narrow dark line in the center and corresponds to the proteins that link together the center region of the adjacent thick filaments