EXSS1010 Lecture Notes - Lecture 10: Human Body, Hydrolysis, Reaction Rate
30 May 2018
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EXSS1010 - WORK AND ENERGY
LECTURE OBJECTIVES
1. Understand the relationship between energy and work
2. Understand and explain with examples the concept of energy conversion
3. Understand how energy is stored and molecules
4. Explain what factors influence enzyme kinetics
5. Define the terms work, power, energy, and net efficiency
6. Give a brief explanation of the procedure used to calculate work performed during cycle
ergometer exercise and step exercise
Energy
• Energy is all around you
• You use energy when you:
o Run
o Squat
o Eat
o Sitting
• Living organisms use it all the time
o Movement
o Growth
o General function
What is energy?
• Energy is the ability to do work
• Joules is the unit for measurement of energy or work
• Work(J) = F (N) x d (m)
• If an object or organism applies force over a distance the object or organism uses energy
• Objects can also gain energy because work is being done on them
• Bioenergetics - the flow and exchange of energy within a living system
Energy Transfer
Energy cannot be created or destroyed. It gets converted from one form to another,
Forms of energy
• Chemical - food
• Mechanical - running
• Heat
• Light (electromagnetic)
• Electrical (electromagnetic)
• Nuclear
Energy conversions
• Energy can be changed from one form to another
o The suns energy (light) can be converted into electricity (solar panel).
o Green plants converts the suns energy into starches and sugars (chemical energy)
o A waterfall and a hydroelectric generator converts mechanical energy into electrical
energy.
Energy states
• Potential (stored energy)
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o Energy associated with a substances structure or position.
o GPE (gravitational potential energy) = mass x gravity const. x height
• Kinetic (movement energy)
o Both mass and velocity influenced
o KE = 1/2 mass x velocity^2
• Total energy of a system = potential energy + kinetic energy
BASICS OF BIOLOGICAL WORK IN HUMANS
Energy Release and Energy Absorption/Conservation
• Endergonic
o Uphill action
o Chemical reactions that store or absorb energy
• Exergonic
o Any physical or chemical process that releases energy into its surroundings
o Downhill action - decline in free energy
Factors that Influence Bioenergetics
• Enzymes - protein catalysts that accelerates the chemical reaction. Providing a platform for a
reaction to occur
• Co-enzymes facilitate enzyme action
Rate of Reaction
• Enzymes do not all operate at the same time, enzyme activity (reaction rate) can be influenced
by:
o Concentration of substrate
o Concentrate of enzyme
o pH and temperature
Enzyme Inhibition
• Competitive inhibitors covers enzymes active site but enzymes cannot change them
• Noncompetitive inhibitors
o Do’t resele ezyes sustrate ot id to its ative site
o Bind to enzyme at a site other than active site to change enzymes structure and ability
to catalyze the reaction
Biosynthesis
• Multi-step, enzyme catalysed process where substances are converted into more complex
products in living organisms
• Specific building-block atoms
o Carbon
o Hydrogen
o Oxygen
o Nitrogen
• Join other atoms and molecules to synthesize important biologic compounds and tissues
• Increase their potential energy
Hydrolysis
• Catabolises carbohydrates, lipids and proteins into simpler forms the body easily absorbs and
assimilates
• Splits chemical bonds by adding H+ and OH- to the reaction by-products
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Document Summary
Energy: energy is all around you, you use energy when you, run, squat, eat, sitting. Living organisms use it all the time: movement, growth, general function. If an object or organism applies force over a distance the object or organism uses energy. It gets converted from one form to another, Forms of energy: chemical - food, mechanical - running, heat, electrical (electromagnetic, nuclear. Energy release and energy absorption/conservation: endergonic, uphill action, chemical reactions that store or absorb energy, exergonic, any physical or chemical process that releases energy into its surroundings, downhill action - decline in free energy. Factors that influence bioenergetics: enzymes - protein catalysts that accelerates the chemical reaction. Providing a platform for a reaction to occur: co-enzymes facilitate enzyme action. Rate of reaction: enzymes do not all operate at the same time, enzyme activity (reaction rate) can be influenced by, concentration of substrate, concentrate of enzyme, ph and temperature.
