Biology
Chapter 4
Chapter 4
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Cartes-fiches
What is energy?
the capacity to do work
3 characteristics of energy
cannot be created or destroyed
is either being used or stored
tends to disperse (spontaneously)
energy allows cells to do what?
life's work
energy exists in what two forms?
potential
kinetic
2 characteristics of potential energy
stored energy available to do work
has the capacity to cause change because of location or structure
2 characteristics of kinetic energy
energy being used to do work
energy in motion
examples of potential energy
chemical energy (stored in bonds)
concentration gradient across a membrane
4 examples of kinetic energy
light
sounds
movement of atoms and molecules
muscle contraction
objects that have the potential to move but are not moving have what?
potential energy
objects that are in motion have what?
kinetic energy
how do we measure energy?
calories
units used to measure energy are what?
calories
the amount of energy required to raise the temperature of 1 gram of water 1 degree Celsius
1 calorie
food is meaured using what?
kilocalorie
1000 calories
1st law of thermodynamics
law of energy conversion
energy cannot be created or destroyed
energy can be converted to other forms
total amount of energy in the universe is constant
the study of energy transformations between work and heat
thermodynamics
What are the forms of energy?
mechanical
heat
sound
electric current
light
radiation
Glucose is a form of what energy?
potential
2nd law of thermodynamics
all energy transformations are inefficient
every reaction loses some energy as heat
process is irreversible
entropy
What is the measure of randomness?
How much energy has been dispersed or disorder is in the system
entropy
kinetic energy contained in the random motion of atoms and molecules
heat
the amount of disorder, or entropy, in the universe is increasing or decreasing?
increasing
the increasing disorder, or entropy, means that energy is doing what?
spontaneously transforming from potential to heat energy
the entropy of the universe is increasing why?
since heat energy is constantly being lost to the universe, and heat energy is disordered
the energy or force holding 2 atoms together is what?
a chemical bond
a chemical bond is a form of what energy?
potential
the making or breaking of chemical bonds
chemical reaction
starting molecules
reactants, or sometimes substrates
all the chemical reactions inside cells
metabolism
two kinds of chemical reactions
endergonic and exergonic
what chemical reaction have products with more energy than the reactants
endergonic
what chemical reaction have products with less energy than the reactants
exergonic
these reactions are not spontaneous
endergonic
these reactions require input of energy
endergonic
example of endergonic reaction
photosynthesis
these reactions are spontaneous
exergonic
these reactions release energy
exergonic
example of exergonic reaction
cellular respiration
all chemical reacitons require an initial input of energy call the
activation energy
the activation energy initiates what
a chemical reaction by destabilizing existing chemical bonds
