Science at a Distance

Biological Energy

This Bio-Module requires the use of the text book "Exploring Life" by Professor John Blamire.

Lecture Notes

a check up

Biological Energy Topic Guide
Lecture Notes - Part 2	Lecture Notes - Part 3

Use this department to check up on the accuracy of your lecture notes. Make sure that you have written down the following definitions, explanations and important concepts in your notes.

Biological Energy - Part One

A Calorie

A calorie is the amount of energy required to raise the temperature of one gram of water from 14.5 to 15.5 degrees centigrade.

a calorie is a unit of measurement that scientist and engineers use to measure energy transactions.
a calorie is a very small unit of measurement. One thousand (1,000) calories is called a kilo-calorie (written kcal). Kcals are more practical units of measurement.
the range of temperature (14.5 to 15.5 degree centigrade) is an important part of the definition. Any other temperature range would result in either a slightly smaller or slightly larger calorie.

Laws of Thermodynamics

First Law: Energy can neither be created nor destroyed, only converted from one form into another

there is a fixed amount of energy in the universe.
this energy comes in many different forms e.g. electrical energy, mechanical energy, light energy, heat energy.
in natural processes, one form of energy is converted into another form of energy.

Second Law: The amount of usable energy in the universe is steadily decreasing, while the level of disorganization is steadily increasing.

potential energy is stored energy, such as the energy found in gasoline or food.
kinetic energy is the energy of motion, such as the rapid movement of molecules in a glass of water.
in all natural processes some potential energy (organized energy) is always converted to kinetic energy (disorganized energy, usually in the form of heat).
as a result, the amount of organized energy in the universe is running down.
the amount of disorder, or randomness in the universe is increasing.
entropy is a measure of this disorder or randomness.

Life and Energy

All living organisms transform energy from one kind to another during their natural processes.

food is fuel. Just as gasoline in an automobile fuels the movement of the car, so food is a fuel that powers the movement of animals.
food is potential energy in a highly organized form.
living organisms transform the organized energy in food into disorganized kinetic energy. Some of this kinetic energy is in the form of work. Some of the kinetic energy is in the form of heat (random motion of molecules).
work is done when a force moves an object through a distance. Animals move, like an automobile moves, when they convert food into the kinetic energy of work (a form of directed motion).

Life, Chemical Reactions and Energy

Inside all cells, millions of chemical reactions are taking place every second. During each of these chemical reactions, energy transformations are taking place. During some chemical reactions organized energy is converted into disorganized energy, these are termed "energy out" or exergonic reactions. During other chemical reactions energy must be added from outside. These reactions are termed "energy in" or endergonic reactions.

Reactions in which organized energy is converted to disorganized energy (exergonic) are obeying the Second Law of Thermodynamics. These reactions occur naturally and spontaneously. They are sometimes called "spontaneous" reactions.
Reactions that require the input of energy from outside the system will not take place unless that extra energy is added. These reactions do not occur without this extra help. They are sometimes called "nonspontaneous" reactions.

Synthesis

Any chemical reaction that joins together smaller components into a larger molecule is called a "synthetic" reaction.

joining together two amino acids to form a di-peptide is a synthetic reaction.
joining together many nucleotides to form a polynucleotide is a synthetic reaction.
all synthetic reactions are endergonic, require an input of energy from outside the system and are nonspontaneous reactions.

Test Yourself with Quick Check Number BE-1025
Lecture Notes - Part 2	Lecture Notes - Part 3
Biological Energy - Topic Guide	Science at a Distance