CHEMISTRY OF LIFEChapter 2

LESSON 1Basic Chemistry

DO NOW

Define, in your own words:

• Atom• Element• Proton• Neutron• Electron

Elements and Atoms

• All matter is made up of substances called elements.• Only 92 naturally occurring elements• Body is composed of only a few elements

• Carbon• Nitrogen• Oxygen • Hydrogen• Phosphorous• Calcium

• Atoms – smallest unit of an element• Made up of:

• Protons – + charge, nucleus of atom• Neutrons – 0 charge, nucleus of atom• Electrons – ( - ) charge, orbit around nucleus

Isotopes

• Same element differs in the number of neutrons in the nucleus and weight.

• Carbon has 2 common isotopes• Carbon-13 and Carbon-14

Radioactive Isotopes

• As isotopes break down they release energy in the form of rays and subatomic particles

• Carbon-14 is a common Radioactive isotope• Unstable and breaks down over

time

http://www.pbslearningmedia.org/resource/nvhe.sci.chemistry.decay/radioactive-decay-of-carbon-14

/

Molecules and Compounds

Molecule – 2 or more of the same atoms bonded together to form a chemical unit

Compound – 2 or more different atoms bonded together to form a chemical unit.

Types of Bonds:Ionic – created by an electrical

attractionCovalent – sharing of electrons

Bonds

Bonds

• Polar Covalent – electrons spend more time with the more electronegative element

• Non-polar Covalent – equally shared electrons

Chemical Bonds

Double Bond – 2 pairs of electrons are shared

Triple Bond – 3 pairs of electrons are shared

In class assignment

• Elements in Living Things Coloring Handout

Homework

• Study Questions pg 39 # 1-4

LESSON 2Water, Acids and Bases

Do Now

• Have your homework from last night out on your desk for me to check!

• What is the difference between ionic and covalent bonds?

• What elements make up the human body?

Organic vs Inorganic

• Organic Molecules – contain carbon• Carbohydrates, proteins, lipids

• Inorganic Molecules – do not contain carbon• Most important molecule is WATER

Water• Polarity and Hydrogen bonding gives

water all of it’s unique and beneficial properties.• Solvent for polar molecules• Cohesive – water molecules stick

together• Adhesive – water molecules stick to

other surfaces• High Specific Heat Capacity/Heat of

vaporization

Video

Acids and Bases

• Acids – substance that separates in water• Bases – takes up hydrogen ions or

releases hydroxide ions

• pH scale – ranges from 0-14, indicates the acidity and basicity of solutions

Acids and bases

pH scale

Acids and Bases

It’s important to maintain body fluid in a narrow pH range. (about 7.4)

Acidosis – pH value drops below 7.35 Occurs when kidneys and lungs can’t keep your pH balanced

Alkalosis – pH value rises above 7.45 Occurs when there is high levels of bicarbonate in your blood Excessive loss of acid Low carbon dioxide level

Buffers – help to keep pH in a normal range they are chemicals or pairs of chemicals that take up excess

hydrogen ions or hydroxide ions

Content Check

• Depending on what you’ve eaten recently, the pH of your urine can vary from 5 to 8.• Which is more acidic – urine at pH 5 of

pH 8

Electrolytes

A substance that releases ions when put into water

These ions can conduct an electrical current

Electrolyte balance is important for good health because it effects the functioning of vital organs.

Homework

• Study Guide Questions pg 39 # 6-7

LESSON 3Molecules of Life

Do Now

• Macromolecules Handout• Hand in Properties of Water Lab

Macromolecules

Molecules of Life

Molecules of Life

^ Dehydration Synthesis- remove water,

make bigger molecules

< Hydrolysis – add water, break down molecules

Carbohydratesquick, short-term cellular energy

• Monosaccharide – one carbon ring. Ex: Glucose, Fructose • Dissaccharide – two carbon rings. Ex: sucrose• Polysaccharide – three or more carbon rings. Ex: starch,

cellulose

Do NowSeptember 30, 2014

Hand in your homework! Take out your notes & be ready to work!

Carbohydrates

Made up of C, H, O in a 1:2:1 ratio Glucose – used as an immediate source

of energy Maltose is 2 glucose molecules, found in

alcoholic beverages Sucrose – glucose & fructose together,

this is table sugar Lactose – glucose and galactose, this is

found in milk

Polysaccharides

Means many sugars, LONG chains of sugar molecules

Starch – energy storage in plants Glycogen – energy storage in animals Cellulose – what cell walls are made up of

We cannot digest this, this helps to scrape the walls of our intestines

Common Polysaccharides

Lipidslong-term energy storage, part of membranes

Saturated Fats - have only single covalent bonds, solid at room temperature. Ex: Butter (usually of animal origin)Unsaturated Fats – have double/triple bonds, liquid at room temperature. Ex: Oils (usually of plant origin)

Lipids

Made of a glycerol molecule and a triglyceride, or three fatty acids.

Can be emulsified – mixed with water, molecules position themselves around a droplet so that their nonpolar ends stick out and the droplet disperse in water

Phospholipids – contain phosphate group, important for cell membranes

Steroids – different structure than fats, back bone of 4 carbon rings, with differing side chains

cholesterol is an example of a steroid

Proteinswide range of functions

• Macromolecules made up of 20 different Amino Acids • Amino acids are arranged as follows

• Central carbon atom• An amino group• An R Group

Structure of Proteins

Composed of amino acids When two amino acids join, called a dipeptide Polypeptide contains 3 or more amino acids

Primary Structure Sequence of Amino acids in a polypeptide

Secondary Structure Coiling or folding of the protein

Tertiary Structure Hydrogen, ionic, covalent bonding all occur in polypeptides

Quaternary Structure Protein that has more than 1 polypeptide, arrangement of

individual polypeptides When proteins are exposed to extreme heat and pH

they denature, and this is irreversible

Protein Structure

Content Check

The sequence of amino acids found in a protein is that protein’s __________ structure

a. primary b. secondaryc. tertiary d. quaternary

Why is it possible for humans to digest starch but not cellulose?a. starch is made of glucose molecules but cellulose

isn’tb. Starch comes from plants but cellulose doesn’tc. The glucose units found in cellulose are linked

differently than those in starch

Enzymes

Protein catalysts Enable particular metabolic reaction to occur

at the body’s normal temperature Energy activation – energy needed to

start a reaction Substrates – reactants in an enzymatic

reaction Enzymes are very specific this is caused

by the shape and chemical composition of it’s active site.

Enzyme Substrate Complex

Nucleic Acidscontain hereditary information

• Two Classes:• RNA – ribonucleic acid, bases are AUGC (codes for proteins)• DNA – deoxyribonucleic acid, bases are ATGC (makes up

genes)

Nucleic Acids

DNA v RNA

ATP

Adenosine plus 3 phosphate groups PRIMARY ENERGY CARRIER IN CELLS Cells require a constant supply

continually break down glucose Some uses:

Synthesizing macromolecules Muscle contraction Conduction of nerve signals

In Class Assignment/Homework

• Macromolecules Worksheet #2