BIOD43H3 Lecture Notes - Lecture 2: Rigor Mortis, Phosphocreatine, Myosin Head
Animal Locomotion and Exercise Notes
Lecture 2: How animals move and the currencies of life
• Performance is quantified as energy, work and power
• Energy = Capacity to do work
-Translating chemical energy into mechanical work
- EX. Lifting heavier= greater work done
- Work measured in Joules & Power measured in Watts
• Potential Energy increases with height making walking up hill/stairs more difficult than
walking on flat ground.
• Locomotion = Transformation of some forms of energy into work and other forms
- work and energy are different because efficiency of transfer is not perfect.
• Chemical energy is utilized as organic carbon molecules are broken down (ex. Lipids,
carbs, and proteins), which is resulted from the harness of radiant energy, such as light
and heat
Muscle
• Energy in muscles supplied through ATP and CrP (Creatine phosphate)
• CrP (Creatine phosphate) is a phosphorylated creatine molecule that serves as a
rapidly mobilizable reserve of high-energy phosphates in skeletal muscle and the
brain to recycle adenosine tri phosphate; which is the energy currency of the cell.
• White meat in chicken breast is muscle with very little to no mitochondria
• Metabolic Efficiency= is the proportion of chemical energy that gets transformed
into mechanical work. Never reaches 100%, energy gets lost.
Muscle Contraction Process
1. Depolarization causes a conformational change in Ca++ channel, which releases Ca++
from the sarcoplasmic reticulum.
2. The Ca++ clears the actin binding sites.
3. During muscle contraction the thin actin filaments slide over the thick myosin filament.
When Calcium is present the blocked active site of the actin filament gets cleared
Step A: Myosin head attaches to actin. (High energy ADP + P configuration)
Step B: Power stroke: myosin head pivots pulling the actin filament toward the center.
Step C: The cross bridge detaches when a new ATP binds with the myosin.
Step D: Cocking of the myosin head occurs when ATP = ADP + P. Another cross bridge can form.
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Document Summary
Lecture 2: how animals move and the currencies of life: performance is quantified as energy, work and power, energy = capacity to do work. Work and energy are different because efficiency of transfer is not perfect: chemical energy is utilized as organic carbon molecules are broken down (ex. Lipids, carbs, and proteins), which is resulted from the harness of radiant energy, such as light and heat. Muscle contraction process: depolarization causes a conformational change in ca++ channel, which releases ca++ from the sarcoplasmic reticulum, the ca++ clears the actin binding sites, during muscle contraction the thin actin filaments slide over the thick myosin filament. When calcium is present the blocked active site of the actin filament gets cleared. Step a: myosin head attaches to actin. (high energy adp + p configuration) Step b: power stroke: myosin head pivots pulling the actin filament toward the center. Step c: the cross bridge detaches when a new atp binds with the myosin.
