Chemistry of LifeChemistry of Life

All matter in the universe consists All matter in the universe consists of elementsof elements

An element is a pure substanceAn element is a pure substance

Examples of elements needed for life:Examples of elements needed for life:CarbonCarbon CCHydrogenHydrogen HHOxygenOxygen OONitrogenNitrogen NNPhosphorusPhosphorus PPSulfurSulfur SS

An atom is the smallest part of an An atom is the smallest part of an elementelement

Can only be seen with the most powerful microscopeCan only be seen with the most powerful microscope

Atoms join together to form molecules.Atoms join together to form molecules.

Examples: Examples: Oxygen we breathe is a molecule made up of 2 oxygen Oxygen we breathe is a molecule made up of 2 oxygen

atoms: Oatoms: O22

Water is 2 hydrogens with 1 oxygen: HWater is 2 hydrogens with 1 oxygen: H22OO

Sugar is a much bigger molecule: CSugar is a much bigger molecule: C66HH1212OO66

How many atoms in one sugar molecule?How many atoms in one sugar molecule?

How do atoms join?How do atoms join?

1.1. Ionic bonds: atoms with opposite Ionic bonds: atoms with opposite charges are attracted to each othercharges are attracted to each other

Example: table salt: NaClExample: table salt: NaCl

2.2. Covalent bonds: strong bonds!Covalent bonds: strong bonds!

Takes energy to break them apartTakes energy to break them apart

Example: water, sugarExample: water, sugar

Important molecules for lifeImportant molecules for life

***Water******Water***

We take it for granted, but water has many We take it for granted, but water has many unique properties that support life.unique properties that support life.

In fact, scientists who look for life on other In fact, scientists who look for life on other plants focus on places where water does plants focus on places where water does or used to existor used to exist

Properties of water

Polar molecule, hydrogen bonds Universal solvent High specific heat Cohesion, adhesion Less dense as a solid (so ice floats) Neutral pH (not an acid or base) Exists on Earth mostly as liquid

Important molecules for life

Carbon-based molecules Why carbon?

1. There’s lots of carbon in the universe

It’s the second largest component of you, after water

2. It can make many different kinds of molecules

Carbon can bond with one, two, three or four other atoms—and it can bond with other carbon atoms to form rings or long chains

The bonds it forms are strong covalent bonds.

Molecules made with carbon that are found in living organisms are called organic compounds

Four types of organic compounds found in living things

Carbohydrates Lipids Proteins Nucleic Acids

These are called macromoleculesMacro = giant (opposite of micro)http://www.authorstream.com/Presentation/PKYonge-422910-pky-biology-macromolecules-macdonald-narrated-education-ppt-powerpoint/

Carbohydrates

Main purpose:

ENERGY!

Carbohydrates

Provide the quick energy that powers all cell functions

Some energy storage (short term) Structural building block

--cellulose—plant cell wall

--chitin—animal exoskeleton

All these carbohydrates are made of three elements: carbon, hydrogen, and oxygen.

Carbohydrates

Sugars Starches

Sugars

All carbs look like this in their simplest form. This is called a simple sugar or monosaccharide.

mono = one saccharide = sugar

Monosaccharides are building blocks for other sugars. If you put two of them together you get this. It’s called a disaccharide. Di = two

Sugars (and starches) are named with the ending -ose

If you string a bunch of monosaccharides together you get a polysaccharide. They look like this. Poly = many

Starches

Polysaccharides are starches.

Plant starch

Amylose – surplus glucose storage Cellulose – structural support in the form

of cell walls

Animal starch

Glycogen – one-day store of glucose in liver and muscles

Chitin – exoskeleton of some insects and cell wall of some fungi

Review

What are carbohydrates made of? What is their major role in the cell? What two major groups are carbohydrates

divided into? What are the building blocks of

carbohydrates? How is starch different from sugar? How are carbohydrates named?

Lipids

Main purposes:1. Storage of energy. In case

you run low on carbs

2. Thermal insulation.

3. Cushioning for delicate organs such as the heart.

4. Waterproofing. Like the wax in your ears.

Lipids

Fats and oils Steroids Phospholipids

Lipids

All lipids are formed from carbon, hydrogen, and oxygen.

Unlike other macromolecules, they are not polymers (made from many copies of one unit or mer)

All lipids are hydrophobic (literally afraid of water): they will not dissolve in water because they are nonpolar molecules.

Fats and oils

Glycerol (an alcohol) + 3 fatty acids

Fats are solids at room temperature while oils are liquids

Fats are efficient energy storage, insulation, and cushioning for organs

Steroids

Cholesterol

Precursor molecule For Vitamin D For hormones such as

Testosterone and Estrogen

Phospholipids

Phospholipids play a very important role in the structure of cell membranes.

Review

What are the different groups of lipids? How are lipids similar to carbohydrates? What property do all lipids share? What important purposes do lipids serve?

ProteinsProteins are composed of 4 elements: carbon, hydrogen, oxygen and nitrogen. The basic unit is called an amino acid and it looks like this.

This is a 3-D image of a protein containing thousands of amino acids connected together & folded to make this distinct shape.

Proteins

All proteins are made from 20 amino acids. Each amino acid is different in one side chain: the “R” in the graphic

A chain of amino acids is called a polypeptide because it is formed by joining amino acids with peptide bonds.

Proteins

Their role in the body: Important part of structures like skin and muscle Antibodies – fight disease Transport – like hemoglobin, the part of blood

that carries oxygen to each cell Regulate what enters and leaves cells –

channels in cell membranes Enzymes – catalyze reactions (lower the amount

of energy needed for chemical reactions essential to cell function to take place)

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html

Proteins make you who you are.

The job of each gene of your DNA is to make a protein with a specific job within the cell.

Nucleic Acids

DNA and RNA!

Their job is to store all your

hereditary information.

More on them later!

Review

What elements are proteins made from? What are the building blocks of protein? What important purposes do proteins

serve? What are enzymes? Why are proteins a uniquely important

macromolecule?