Chemistry of Life: Atom: the basic unit of matter For practical purposes, all mass is in the nucleus. Each proton and neutron has a mass of one AMU (atomic.

Chemistry of Life:

Atom: the basic unit of matter

For practical purposes, all mass is in the nucleus.

Each proton and neutron has a mass of one AMU (atomic mass unit). An electron has a mass of 1/1840 AMU (we’ll call that negligible).

Because all atoms have an equal number of protons and electrons, all atoms have no electrical charge (neutral).

We identify atoms by their atomic number (number of protons).

Helium

Isotopes of an element have different numbers of neutrons, and therefore , different masses.

Three isotopes of hydrogen

Mass Numbers: 1 2 3

…but the atomic mass of Hydrogen on the Periodic Table is

1.0079

This is a “weighted average”, indicating that in nature there are many more H1 atoms than there are H2 or H3 atoms.

Carbon Dating

Measuring the relative amount of a radioactive isotope to determine how old something is.

Chemical Bonds:Remember those valence electrons?

Ionic and Covalent Bonding

Ionic

Covalent

Water

Water’s polarity allows it to hydrogen bond and to dissolve polar molecules and ionic compounds (any charged substance)

Organic Chemistry(the chemistry of organisms)(the chemistry of Carbon…what is special about Carbon, chemically speaking?)

Macromolecules are polymers made by combining many smaller monomers…think of a chain of paper clips.

Functional groups you should get to know:

-OH alcohol-NH2 amino-COOH carboxyl

Dehydration Synthesis

Break the word apart…synthesis means “putting together”, so this will be an anabolic reaction. Dehydrate means “take water away”.

HydrolysisLysis means to break apart, and we’re breaking a molecule apart using water.

Watch and learn…

Carbohydrates

•Made of carbon, hydrogen, and oxygen

•In a 1 : 2 : 1 ratio

•Used as energy source (glucose, a monosaccharide)

(sucrose is a disaccharide)(starch and glycogen and both

polysaccharides)

•Can also be structural (cellulose in plant cell walls is a polysaccharide)

Lipids

•Mostly carbon and hydrogen

•Fats, oils, and waxes

•Store energy, part of cell membranes and waterproof coverings

•Can be saturated with hydrogens (all single bonds in the chain)

•Can also be unsaturated (double or triple bonds between carbon atoms)

Proteins•Contain C, H, O, AND Nitrogen

•Structural, enzymes, immunity, transport in/out of cells, pigments, etc.

•Made of monomer units called amino acids

•Amino acids contain an amino group, a carboxyl group, and an “R” group

Proteins are formed by making a long chain of amino acids…the amino group of AA1 bonds to the carboxyl group of AA2 by dehydration synthesis, forming a peptide bond (and releasing a water molecule).

Watch animationAnother animation

This makes the primary structure of a protein.

Folding and twisting of specific areas of the chain or very large areas of the protein make the secondary and tertiary structures of the protein.

Finally, several large, folded chains of amino acids come together and bond to one another in a very precise, specific way, such as in this hemoglobin molecule. This is the quaternary structure.

Nucleic Acids

We’ll be learning about these in a lot of detail in the future. Important for this unit are the following facts:

•Contain C, H, O, AND Nitrogen and Phosphorus

•Monomer is a 3-part nucleotide

•Store and transmit genetic information in a molecule that can be passed to the next generation in special cells

Review video(please mute volume if you find sad what happened to a classic rock band from Woodstock)

Proteins need to keep this exact shape because they often bind to other molecules based on their shape and charge.

Enzyme-substrate animation