471723
Description
Mind Map by kirareynolds, updated more than 1 year ago
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Created by kirareynolds
over 10 years ago
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Sliding Filament Model cont.
- Calcium Ions allow Muscles to Contract
- The binding sites for the
myosin head group on the
actin fibre are covered by
the tropomyosin subunits,
meaning that a myosin
head group cannot attach to
any such binding site nor
can cross bridges form or
muscle contraction occur
- When an action potential
arrives, via neurone, at the
neuromuscular junction,
calcium ions are released
from the sarcoplasmic
reticulum in the sarcomeres.
- These calcium ions diffuse
through the sarcoplasm and
bind to the troponin molecules
- This binding changes
the shape of the
troponin, which moves
the tropomyosin away
from the binding sites
on the actin
- The actin- myosin binding
sites are uncovered and so
cross bridges can firn, This
allows the power stroke and
muscle contraction to occur.
- The actin- myosin binding
sites are uncovered and so
cross bridges can firn, This
allows the power stroke and
muscle contraction to occur.
- This binding changes
the shape of the
troponin, which moves
the tropomyosin away
from the binding sites
on the actin
- These calcium ions diffuse
through the sarcoplasm and
bind to the troponin molecules
- When an action potential
arrives, via neurone, at the
neuromuscular junction,
calcium ions are released
from the sarcoplasmic
reticulum in the sarcomeres.
- The binding sites for the
myosin head group on the
actin fibre are covered by
the tropomyosin subunits,
meaning that a myosin
head group cannot attach to
any such binding site nor
can cross bridges form or
muscle contraction occur
- The Role of ATP in the Power Stroke
- When the myosin head group attaches to the
actin binding site and bends, the molecules
are in their most stable form.
- Energy from ATP is
required in order to break the
cross bridge connection and
re-set the myosin head
forwards
- The myosin head group
can the attach to the next
binding site along the actin
molecule and bend again
- The myosin head group
can the attach to the next
binding site along the actin
molecule and bend again
- Energy from ATP is
required in order to break the
cross bridge connection and
re-set the myosin head
forwards
- When the myosin head group attaches to the
actin binding site and bends, the molecules
are in their most stable form.
- Maintenance of ATP Supply
- In order to allow for continued
contraction, ATP must be regenerated as
quickly as it made up.
- Aerobic respiration in muscle cell
mitochondria: dependent on the supply of
oxygen to the muscles and the availability
of respiratory substrate.
- Anaerobic respiration in the
muscle cell sarcoplasm:
Quick process, leads to
lactic acid (toxic).
- Transfer from creatine
phosphate in the
muscle cell
sarcoplasm
- In order to allow for continued
contraction, ATP must be regenerated as
quickly as it made up.
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