Upgrade to remove ads
Terms in this set (67)
The analysis of how energy powers the activities of living systems
The capactiy to do work
How is energy used?
Energy is used by organisms to create ordered complexity--energy had to be used to create order from chaos
What processes is energy used for?
Growth, Reproduction, Responsiveness, to Maintain Homeostasis
Where does energy come from
The majority of energy that enters the life system originates from the sun.
is 1367 W/m^2. the irradiance of the sun on Earth's outer atmosphere.
Isolated thermodynamic system
No energy or mass exchanged. (for example you would hope a thermos would be an isolated system)
Closed thermodynamic system
energy is exchanged but not mass (for example between the sun and earth)
Open thermodynamic system
Energy and mass is exchanges (for example an animal)
Solar constant compared to what makes it passed the atmosphere
The amount of energy that make it to earths outer layer is much higher than what makes it passed the atmosphere. This is a result of absorption scattering
How does position on the earth affect energy budget?
The equator receives more energy than the poles because the sun hits more directly. the same amount of energy is spread over a larger area.
Consequences for life on Earth as a result of differences in energy
Less incoming energy from the sun means less plants, and fewer animals as a result
Two states of energy
Potential--Stored energy; Kinetic--energy of movement
Types of potential energy
Chemical: energy stored in the bonds of atoms and molecules, ie. sugars
• Nuclear: energy stored in the nucleus of an atom - the energy that holds the nucleus together
• Gravitational: result of an object's vertical position or height
• Mechanical: stored energy of position, once object is moving the energy is converted to kinetic
Types of kinetic energy
Sound: vibrations of particles caused by one object applying a force to another object
Thermal: vibration of particles within an object
kinds of energies released
into space by stars
• Radio Waves
• TV waves
• Radar waves
• Ultraviolet Light • X-rays
• Short waves
• Gamma Rays
energy is never lost but often changes forms
Energy utilized for life
A very small fraction of the solar energy reaching the surface of the earth is captured by the life system.
radiant energy (kinetic) to chemical energy (potential) that is stored in covalent bonds between atoms in sugar molecules
type of chemical bond that involves sharing of pairs of electrons between atoms
How is the strength of a covalent bond measured?
The strength of a covalent bond is measured by the amount of energy required to break it.
When is bond strength important
In chemical reactions--the formation or breaking of chemical bonds
What influences the rate of chemical reactions
Environment (temperature, pH, moisture) Concentration of reactants and products Catalysts
A specific type of chemical reaction that are biologically important. electrons (e-) are transferred between atoms or molecules, while still retaining their energy of position
Energy pf position
Distance of an e- from the nucleus of the atom.
loss of e-. often HYDROGEN that gets oxidized
gain of e-. often OXYGEN that gets reduced
Oxidation is Loss Reduction is Gain
How strongly a nucleus attracts e-. H has a weak hold on e- and O has a strong pull
The Laws of Thermodynamics
Rudolf Clausius. govern all energy changes in the universe. 2 laws
The energy of the universe is constant. Energy can neither be created nor destroyed, it can only change forms. Heat energy lost to environment
with every change, but heat cannot do work.
The entropy (disorder) of the universe tends to a maximum (is always increasing). Disorder is more likely than order.
Will a reaction occur spontaneously?
Determine if the disorder (entropy) of the system will increase more than order (enthalpy)
as the reaction proceeds.
Gibbs Free Energy (G)
the energy available to do work
G = H (enthalpy) - TS (entropy)
When will a reaction occur spontaneously
If ΔG is negative (ie. disorder > order), reaction will proceed spontaneously!
Not spontaneous, energy must be supplied
Spontaneous, releases energy
If chemical reactions that release free energy occur spontaneously, then why haven't ALL such reactions already occurred?
Even exergonic (spontaneous) reactions need a kick start to 'set the wheels in motion'- to break chemical bonds.
energy required to initiate a chemical reaction by destabilizing the chemical bonds of the reactants. Rate of reaction depends on how big of a kick is required.
Speeding up chemical reactions
Generally need a big kick start to begin a reaction. Catalysts can lower activation energy.
process of lowering activation energy by stressing chemical bonds of reactants so they break more easily.
the substances involved- must always obey the laws of thermodynamics
- most are 3-D Proteins
- most processes in a cell need enzymes in order to occur at significant rates
- not consumed in the reaction
- increase reaction rates by several orders of magnitude
Add in rate of enzymic reactions from lab
Examples of Biological Catalysts: Enzymes
Synthesis of antibiotics. Cleaning products (break down protein/fat stains-->clean)
Enzyme binding its substrate
Substrate is the "key"
•amino acids start to break down bonds
•lowers activation energy needed to break down bonds
models enzyme kinetics.
relates reaction rate (v) to the concentration of substrate [S].
Vmax = the maximum rate achieved by the system, at maximum (saturating) substrate concentrations.
Km = Michaelis constant and is the substrate concentration at which the reaction rate is half of Vmax.
Michaelis-Menten saturation curve
• Km is an inverse measure of the substrate's affinity for the enzyme • different enzymes have different Km values
Factors that affect Km
pH, ionic strengths, temperature, nature of the substrate
Enzyme Activity Affected by...
• Concentration of the substrate and enzyme
• Chemical environment (ie. pH)
• Other molecules
- inhibitors & activators
- co-factors & co-enzymes
What happens to enzyme reactions of the wrong temps
Below Optimum Temperature: enzyme shape is not flexible, so no induced fit.
Above Optimum Temperature: the molecular bonds within enzymes are too weak to maintain the induced shape
Too high of a temperature: enzyme denatures. enzyme loses structure
Optimal Enzyme pH
most enzymes have an optimal pH range between 6 and 8
• there are enzymes that function best in low pH (high acidity) environments
Inhibitors - molecules that decrease enzyme activity.
Cofactors & Coenzymes
non-protein chemical molecules that sit near the active site and assist enzyme function by acting as e- acceptors
important cofactor in redox reactions
important coenzyme in redox reactions. energy-rich molecule that cells use for energy. High-energy & unstable bonds low activation energy! (high potential energy)
Why is there only a small pool of ATP is present within the cells at any given moment
It is too unstable
all chemical reactions that occur in living organisms.
- made up of a network/series of exergonic & endergonic reactions
- catalyzed by enzymes
What are the main purposes of metabolism
1. convert food to energy to run cellular processes
2. convert food to building blocks for proteins, lipids, nucleic acids and some carbohydrates
3. elimination of nitrogenous wastes
require energy to synthesize molecules (endergnoic metabolic reactions)
produce energy by breaking molecules
(exergonic metabolic reactions)
are sequences of linked chemical reactions that together enable coherent metabolic activity within in an organism.
Anabolic reactions + catabolic reactions = biochem pathways
How can pathways be arranged?
Pathways can be arranged in a membrane
soluble, with enzymes and substrate floating around in the cytoplasm of cells...
ie. Pyruvate Dehydrogenase
• made of many copies of 3 different enzymes
• performs 3 sequential reactions
• critical in cellular respiration
• lack of it deprives the body of energy, short life span
(enzyme changes shape of substrate as is moves along)
Multi-enzyme Complexes are advantageous because...
• Lower reaction time by supplying substrates directly to subsequent reactions.
• Limits secondary reactions because competitive inhibition is prevented.
• Combined regulation is possible since the
enzymes are acting as a single unit. (feedback inhibition)
The end product substrate can plug in to the enzyme and stop the biochemical pathway from continuing
Recommended textbook explanations
Kenneth R. Miller, Levine
Nelson Science Perspectives 10
Christy C. Hayhoe, Doug Hayhoe, Jeff Major, Maurice DiGiuseppe
Miller & Levine Biology, Foundation Edition
Joseph S. Levine, Kenneth Miller
Alton Biggs, Hagins
Sets found in the same folder
Sets with similar terms
Chapter 6 the energy of life
Biology (Dr. Jones) Unit 3
Human Physiology Silverthorn 7e, Chapter…
Chapter 6 energy & metabolism
Other sets by this creator