1122 Chem of life 1

Matter

anything and everything that has mass and takes up space

in the universe

• Can be solid, liquid or gas (even in the human body)

• Most of the time can see, smell, touch, feel it

Energy

the capacity to do work or put

matter into motion

• You cannot touch it, but rather only

feel its effects on matter

Kinetic Energy

Energy in action

• Ex: a ball bouncing

Potential Energy

• Stored energy

• Inactive but has the capacity, the

“potential” to do work

• Ex: battery, water held back by a dam

Forms of Energy and how they present in the body

• Chemical

• Electrical

• Mechanical

• Radiant/Electromagnetic

Energy is neither….

created or destroyed, rather

converted and/or transferred

All energy conversions in the body generate/liberate…

heat

Chemical Energy

Potential energy stored in bonds of chemical substances, Most useful form of energy in living systems, ie burning wood, food we eat

Electrical Energy

Results from the movement of charged

particles, ie nervous system

Mechanical Energy

The energy that is directly

involved in

movement/moving of

matter

• Running, jumping,

throwing, etc…

Radiant or Electromagnetic Energy

Energy that travels in waves

• Waves vary in length and collectively are called

the electromagnetic spectrum

• Includes: radio waves, x-rays, UV light,

visible light

• In the human body:

• light energy stimulates the retina

Elements

unique forms of matter with specific

chemical and physical properties that cannot be broken

down into smaller substances by ordinary chemical

reactions

The four elements common to all living organisms are:

oxygen (O)

• carbon (C)

• hydrogen (H)

• nitrogen (N)

• Above 4 elements make up 96% of our bodies!

Molecules

Most atoms do not exist alone, rather they combine with other atoms

• When 2 or more atoms of the same element combine, the resulting

substance is called a molecule of that element

• Examples:

• 2 hydrogen ions bound together are hydrogen gas (H2)

• Oxygen is O2

Compounds

• When 2 or more different kinds of atoms combine, they form

molecules of a compound

• Ex:

• 2 hydrogen + 1 oxygen form the compound water (H2O)

• 1 carbon + 4 hydrogen forms Methane (CH4 )

Mixtures

substances composed of 2 or

more components physically intermixed

Solutions

Homogenous mixtures of

components

• Can be in the form of:

• Gas

• Liquid

• Solid

Solvent

Substance present in the

greatest amount

• Dissolving medium

• Water is the body’s chief solvent

Solutes

• Substance present in smaller

amount

• That which is dissolving in the

solven ie salt in salt water

True Solutions

a homogeneous mixture of two or more substances where the solute particles are completely dissolved at the molecular or ionic level

Colloids

Also termed emulsions

• Heterogeneous mixtures

• Their composition is not always the same

throughout different areas of the mixture

• Can appear transparent or milky

• Particles are larger than in a solution but still they

DO NOT settle out

• They DO, however, absorb or scatter some light

• Light shined through will be visible

• Can undergo sol-gel transformation

• Can change reversibly from a fluid to semi

solid, “gel” form

• Ex: Jello

Suspensions

Heterogeneous mixtures

• Heterogeneous mixtures that

contain large, visible solutes

that do settle out

• Example: mixture of water

and sand

• Blood is considered a

suspension because if left in

a tube, the blood cells will

settle out

Ionic Bonds

transfer of electrons

ions

Charged particles

formed and they can

be (+) or (-)

Cation

an electron donor

• Loses an electron to another atom, therefor

acquires a positive (+) net charge

Anion

an electron acceptor

• Takes on an electron

• Acquires a negative (-) net charge

Hydrogen Bonds

• More like attractions rather than true bonds

(different from ionic and covalent)

• Formed when a weakly positive hydrogen

atom already bonded to one electronegative

atom (for example, the oxygen in the water

molecule) is attracted to another

electronegative atom from another molecule.

Hydrogen Bonding

Between Polar Water

Molecules

In other words, hydrogen

bonds always include

hydrogen that is already part

of a polar molecule.

• Forms a “bridge” responsible

for the tendency of water

molecules to cling together

and form films, and

beads/spheres

Chemical reactions

occur when chemical

bonds are formed, rearranged, or broken

• These reactions can be written in symbolic

forms called chemical equations

Reactants

substances entering into

reaction together

Productts

resulting chemical end

products

Synthesis

(combination) reactions involve:

atoms or molecules combining to form larger

molecules, used in anabolic (building)

processes, requires energy

A + B = AB

Decomposition

reactions involve breakdown

of a molecule into smaller molecules (revers

of synthesis), involves catabolic (bond

breaking) reactions, releases energy

AB → A + B

Exchange reactions

(also called displacement

reactions) involve both synthesis and

decomposition

• Bonds are both made and broken

AB + C → AC + B

The speed of chemical reactions can be affected by:

• Temperature: increased temperatures usually increase rate of

reaction

• Concentration of reactants: increased concentrations usually

increase rate

• Particle size: smaller particles usually increase rate

Catalysts

increase the rate of reaction without being chemically changed or

becoming part of the product

Enzymes

biological catalysts; proteins that have the ability to bind substrate in their active site and

then chemically modify the bound substrate, converting it to a different molecule —

the product of the reaction.