2/6- Muscular System Continued (Exam 1) Flashcards
What are z lines?
Mark on sarcomeres edges
Lines between each
What happens when the z line gets pulled?
If you pull them in a little bit but many of them the whole chain shortens dramatically causing the muscle cell to shorten dramatically
What is an active or binding site in an actin protein?
Where the head of myosin attaches to
What is a cross bridge?
The connection between myosin and actin
Does the head of the myosin move?
Yes back and forth
Does the myosin crawl along actin and gives movement to the z lines in the sarcomeres?
Yes
What is a power stroke or working stroke?
When myosin goes off like a mouse trap
Doesn’t use ATP
What are the 4 steps of the myosin connection to actin?
1) myosin locks on to actins active site (cross bridge) and has ADP attached to myosin
2) the tail of myosin gets pulls and ADP let’s go and ATP attaches
3) ATP resets the mouse trap and myosin straightens out again and now ATP became ADP
4) another cross bridge is set to another active site on the actin
What breaks the cross bridge?
ATP attaching to the head of myosin
What is rigor Morris and what causes it?
Stiffness in muscle after death
Stop taking in oxygen, electron transport chain stops and ATP isn’t formed
Myosin remains locked in cross bridges
Stiffness ends because of early stages of decomposition
What is the sliding filament theory?
Myosin filament is sliding across actin filament
Actin is being moved because myosin cannot
This causes z lines to move towards one another and shorten
In science, what is a theory?
Survived multiple attempts at trying to prove it wrong
What are the 4 proteins of a sarcomere?
1) Actin
2) myosin
- movement
3) tropomyosin
4) troponin
- on/ off switch
What is tropomyosin?
Covers active site on actin so myosin cannot attaches
Long filaments sitting over active sites
What is troponin?
Globular protein (round shape)
If changed shape it will pull tropomyosin away from active sites to allow myosin to attach
