Microbiology Chapter 2 (Nester)

Atoms

The basic units of all matter and are made up of three major components. (Neutrons, Protons, and Electrons)

Neutrons

Uncharged particles

Protons

Positively charged particles

Electrons

Negatively charged particles

Element

Consists of only one kind of atom and cannot be separated into simpler parts by chemical methods.

Ion

An atom that gains or loses an electron that is no longer neutral.

Cations

Positively charged ions.

Anions

Negatively charged ions.

Ionic Bonds

Form between cations and anions because of strong attractions between positive and negative charges. The resulting product is usually a salt.

Covalent Bond

When atoms share pairs of valence electrons. One pair of shared electrons is this. Very strong.

Molecule

Two or more atoms joined together by a covalent bond.

Compound

A molecule consisting of more than one element.

Organic Compound

Carbon atoms joined by covalent bonds to hydrogen atoms form this.

Inorganic Compound

All other compounds in life.

Non-polar covalent bond

When electrons are shared equally.

Polar Covalent Bond

When electrons are shared unequally.

Hydrogen Bonds

Weak bonds formed when a hydrogen atom in a polar molecule is attracted to an electronegative atom in the same or another polar molecule.

Hydrophilic

Water loving. (Salts and polar molecules)

Hydrophobic

Water fearing. They do not dissolve in water because they cannot form hydrogen bonds.

pH

A measure of somethings acidity.

Buffers

Compounds that stabilize the pH of solutions.

Adenosine Triphosphate (ATP)

The energy currency of a cell.

Macromolecules

Large molecules. There are four major classes. Most are polymers.

Proteins, Carbohydrates, Nucleic Acids, and Lipids

Four major classes of macromolecules.

Polymers

Subunits that are joined together

Dehydration Synthesis

A chemical reaction that removes h20.

Hydrolysis

The reverse reaction of breaking a macromolecule down to its subunits by adding h20.

Enzymes

Chemical reactions require specific __________.

Catalyzing Reactions, Transporting Molecules, and Motility

Name 3 most important roles of proteins.

Amino Acids

Subunits that make up proteins. There are about twenty major ones and can be arranged into a number of combinations in a protein.

Protein

One or more long polypeptides folded to create a functional molecule.

Peptide Bonds

Amino acids are held together in an unbranched chain.

Carbohydrates

A diverse group of compounds that include sugars and starches. They play several critical roles in biology.

Energy Source, Energy Storage, Source of Carbon, Structural Components

Name 4 critical roles that carbohydrates play in biology.

Monosaccharides

Simple Sugar.

Disaccharides

Two monosaccharides joined together by covalent bonds.

Polysaccharides

Are large molecules composed of long chains of monosaccharide subunits or their derivatives.

Nucleic Acids

Carry genetic information.

DNA

The master molecule of the cell. The nucleotides have 3 different parts which are a nucleobase, deoxyribose, and a phosphate group.

RNA

Involved in the process that decodes the information in DNA to create a sequence of amino acids in proteins.

Lipids

Critically important in the structure of membranes, which function as cells gatekeepers. Very diverse group and are highly soluble in water. Most common are fat.

Phospholipids

Contain a phosphate group linked to one of a variety of other polar molecules. Considered a compound lipid.

Steroids

Simple lipids that have a characteristic structure consisting of four connected rings.