Unit 1 Notes: Chemistry

All Biology consists of ChemistryAll organisms are made up of

matter. Matter is anything that takes up space and has mass.

Matter is made up of one or more chemical elements. An element is a pure substance that cannot be broken down into any other substances.

ElementsThere are about 25 different elements that

are essential for life 4 main elements that make up the majority

of living matter are; oxygen, carbon, hydrogen, and nitrogen.These make up 96% of living matter

And then there are trace elements that are just as important for your body to function correctly, but they are found in very small amounts; iodine, iron. Trace elements make up less than 0.01%

of your body!

CompoundsCompounds are substances that are made

up of two or more elements. These elements are put together in specific ratios.

For example, there are 2 hydrogen's needed for every oxygen in water (H2O)

A compounds properties can be very different for the individual elements that it is made up of.

Most compounds are made up of 3 or 4 different elements (C6H12O6)

Atoms An atom is the absolute smallest part of an

element.Atoms are made up of:

Protons which have positive chargesElectrons which are negatively chargedNeutrons which are neutral They give an element its physical and

chemical properties depending on how the protons, neutrons and electrons are arranged.

Where are the parts of an atom found?In an atom you find the protons and

neutrons in the nucleus, the electrons orbit around the nucleus in a “cloud”.

All atoms of an element have the same atomic number or protons, it is the number of neutrons that can change.

IsotopesAn isotope is formed when an element has

the same number of protons in the atom but changes numbers of neutrons in its nucleus.

***Adding a proton makes a new kind of atom, Adding a neutron makes an isotope of that atom and a heavier version of that atom

Some elements can have quite a few different forms because there are several different numbers of neutrons found in nature.

For example:

Radioactive IsotopeAs more neutrons are added to the

nucleus, the atom becomes unstable making the nucleus decay or give off energy.

This matter and energy given off is radiation, which can be damaging, but also has many medical uses.

An enriched form of water with an isotope of oxygen is the basis for PET scans to detect brain, heart, and abdominal cancers.

Electrons are important in chemical bonds!

An atoms structure and arrangement of electrons determines how that atom will react with another.

When electron energy levels are not completely filled, the atoms are chemically reactive.

The atoms want to have a filled energy level, so bonds are formed to make this happen.

Bonds There are two types of bonds that we will

talk about: 1. Ionic bonds-one atom transfers

electrons to another atom This transfer makes the atom that has

lost the electron positive and the atom that has gained the electron more negative

The two atoms that have changed are know as ions. A positive ion=cation: A negative ion=anion.

2. Covalent bonds-two atoms share electrons. Two or more atoms held together by covalent bonds=molecule

Chemical ReactionsAtoms are constantly being

rearranged by chemical reactions which can form new substances.

This rearrangement can be easily seen in a chemical equation which is very much like a math equation.

The starting material, or what goes into the reaction, are the reactants.

The ending material, or how the reactants combine together, is known as the products.

It is important to remember that chemical reactions do not create or destroy atoms, they only rearrange them.

With this rearrangement there are new bonds forming and other bonds breaking.

Elements are listed on the periodic table in an order based on number of protons.

# protons = # electronsWhy aren’t there the same amount of

neutrons too?Because of isotopes!

• Different number of neutrons can change the type of element.

•Element Equations on Periodic Table

*Number of Protons = Atomic Number

*Number of Electrons = Number of Protons

= Atomic Number

*Number of Neutrons = Atomic Mass – Atomic Number

How many protons?36

How many electrons?36

How many neutrons?84 – 36 = 48

# protons = 42# electrons = 42

# neutrons:96 – 42 = 54

The Role of Carbon in OrganismsA carbon atoms has 4 electrons

available for bondingHas a great ability to bond with other

atomsLarge carbon compounds (thousands of

carbon atoms) are called biomoleculesEX: Proteins

Polymer: large molecule formed when MANY smaller molecules bond together

CarbohydratesCarbohydrates give energy to cells.

Carbo-load before a big race? It really works!Carbohydrate: biomolecule of carbon, hydrogen, and

oxygenEX: Monosaccharide (simple sugar): glucose,

fructose. EX: Polysaccharide (many sugars): starch,

glycogen, celluloseGoing on a carb-free diet?

Your body doesn’t need as many carbs as you give it on a daily basis because we store carbohydates!

However, you still need carbs every day, your cells need their energy to keep you living.

LipidsLipids: large biomolecules made mostly

of carbon and hydrogen with a small amount of oxygen.

EX: fats, oils, waxes, and steroids.Don’t think about getting rid of lipids from

your diet just yet!Cells use lipids for energy storage,

insulation, and protective coverings.The major components of cell

membranes are lipids

ProteinsProtein: large, complex polymer composed

of carbon, hydrogen, oxygen and nitrogen.Proteins are essential to all life.

Provide structure for tissues/organs and carry out everyday cell processes

Amino Acids: basic building blocks of proteins

About 20 common amino acids that we will cover in the DNA unitEver hear of tryptophan on Thanksgiving?

EnzymesEnzyme: protein that changes the rate of a

chemical reaction.Enzymes are involved in nearly all

metabolic processes. In some cases, enzymes speed up

reactions that otherwise would be slow.EX: speed up digestion of foodEnzyme activity depends on temperature

and pH conditions.