﻿ Pinciples of Biology: Physics
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BI-122 Biology
Physical Basis of Life

# basic Physics

## General characteristics of the Universe:

• made of Matter and Energy
• total amount of matter and energy is fixed
• Matter (m) is conserved
• Energy (E) is conserved
(The 1st Law of Thermodynamics)
• except in nuclear events, where E = mc2

## MATTER

### Atomic structure

 MATTER substances compounds molecules sub-molecular elements atoms sub-atomic electrons m = 0 amu, chrg = -1 protons m = 1 amu, chrg = +1 neutrons m = 1 amu, chrg = 0

• small, dense nucleus
• protons [number = atomic number]
• neutrons [mass (protons + neutrons) = atomic mass
• isotope = atom with different number of neutrons
same atomic number
different atomic mass
• probability cloud
• electrons
• usually equal to number of protons
• charge on atom = charge of protons + charge of electrons
• when charge on atom ≠ 0, atom is called ion

### states of matter

 STATES OF MATTER state volume shape other plasma variable variable emits light gas variable variable liquid constant variable plastic constant constant moldable solid constant constant crystaline

• listed in declining energy (kinetic) level of particles
• state changes accompanied by change in energy
• movement up table requires addition of energy
• movement down table releases energy
• density decreases as energy increases

## ENERGY

### The 2nd Law of Thermodynamics

When Energy is changed from one form to another,

• some of the energy is lost as heat
• Entropy (disorder) tends to increase

Life is highly ordered, which is against the Laws of Physics

• This is a capital offense; that is, Life causes Death
 ENERGY type example kinetic motion potential stored position chemical mechanical heat