Sliding Filament Theory Flashcards
whats Sarcoplasm
cytoplasm of muscle fibres
whats Sarcoplasmic Reticulum
storage sites for calcium , surrounding myofibrils
Whats Tropomyosin
long protein filament that blocks or exposes the binding sites of myosin heads , bands that run along the actin filament ( allows muscles to relax by attaching to actin)
Whats troponin
a protein attached to tropomyosin (acts as glue) , attachment site for Calcium ions (necessary for muscle contraction)
whats the sliding filament theory
how muscles contractions occurs
In the sliding filament theory wgat comes together
Z lines move closer together , actin moves not myosin
in the sliding filament theory what’s happening
Z lines move closer together, sarcomere shortens , actin filaments move in and slide over myosin filaments (myosin n actin filaments dont change in length
where does energy for sliding filament theory come from
ATP
What is happening in relaxed state of Sliding filament theory
-Myosin head is not contacting the actin
- Calcium is absent
- Tropomyosin blocks the myosin binding sites on actin
- tropomyosin is held in position by troponin
what happens in cross bridge step 1
- Calcium ions are released from the sarcolemma upon stimulation
- Calcium binds to troponin (makes it not sticky) and moves the tropomyosin away from the binding sites
- the heads of myosin attach to binding sites on the actin filaments
what happens during Power Stroke step 2
The myosin head pulls back and moves actin with it
What happens in detachment step 3
ATP binds to the myosin head causing the myosin to let go of the actin
what happens in the step 4 hydrolysis
- when ATP binds to myosin it breaks down into ADP , Pi and energy
- Calcium detaches from troponin and is reabsorbed
- Tropomyosin moves back ti its original position and blocks the myosin binding sites again
- Creatine Phosphate regenerates ATP
Where is energy for muscle contraction gained from
breakdown of creatine phosphate (anaerobic ), aerobic cellular respiration and lactic acid fermentation (anaerobic)
ATP is ____
ADP is _____
charged
not charged , lazy version
aerobic is
with O2
anaerobic is
without O2
whats creatine phosphate and whats it for
a high energy compound that builds up when muscle is resting and the fastest way to male ATP availableto muscles
how long does creatine phosphate provide energy
8 sec of intense activity and then it is spent
What does creatine phosphate initially do
supplies phosphate to ADP (not active) to get ATP before O2 enters mitochondria
Creatine Phosphate is a ________ system to get ATP energy
anaerobic (no O2)
Aerobic Cellular respiration takes cb place in _____
mitochondria
what dose aerobic cellular respiration do
provides most of the muscles ATP with O2
what happens during aerobic cellular respiration to create ATP
glycogen and fats are stored in muscle cells to be used a fuel to produce ATP when O2 is available
Myoglobin in muscle cells stores oxygen during muscle contraction
CO2 water n heat r produced as wastes
Myoglobin in muscle cells
stores O2 for use during muscle contraction