Microbiology Chapter 2: Atomic Structure, Chemical Bonds, Organic Molecules, and pH

What is the basic unit of matter?

An atom.

What is matter?

Anything that has mass and takes up space.

What are the 3 sub-atomic particles?

Protons, neutrons, and electrons.

Which sub-atomic particle has a negative charge?

Electrons.

Which sub-atomic particle has a positive charge?

Protons.

Which sub-atomic particle has no electrostatic charge?

Neutrons.

A positively charged atom is specifically called what?

A cation.

List an example of a cation.

Na⁺ (sodium).

A negatively charged atom is specifically called what?

An anion.

List an example of an anion.

Cl⁻ (chloride).

The atomic number of an atom is derived from the quantity of what sub-atomic particle?

Protons.

The atomic mass (mass number) is derived from what sub-atomic particles?

Protons and neutrons.

Which sub-atomic particle varies in an isotope?

Neutrons.

Chemical bonds formed by the "sharing" of electrons are called what?

Covalent bonds.

Chemical bonds formed by the "stealing" of electrons are called what?

Ionic bonds.

Which type of bond is a weak attraction involving hydrogen and an electronegative atom?

Hydrogen bonds.

What is a hydrogen bond?

A weak bond between hydrogen and an electronegative atom.

What is molarity?

The number of moles dissolved in 1 liter of solution.

In 2H₂ + O₂ → 2H₂O, what are the reactants and products? How many water molecules form?

Reactants: H₂ and O₂. Product: H₂O. 2 water molecules are formed.

Is water a polar molecule?

Yes.

Do charged substances dissolve in water?

Yes.

What does hydrophilic mean?

Water-loving; dissolves in water.

Do uncharged substances dissolve in water?

Nonpolar substances usually do not.

What does hydrophobic mean?

Water-fearing; does not dissolve in water.

Which measurement is used to quantify the acidity of an aqueous solution?

pH.

What is the range of the pH scale?

0-14.

Would a pH of 2.0 be acidic or alkaline?

Acidic.

Would a pH of 12.0 be acidic or alkaline?

Alkaline (basic).

What pH is considered neutral?

7.

What is the pH of human blood?

About 7.4.

What does a chemical buffer do?

Helps maintain a relatively constant pH.

List the 4 categories of organic molecules.

Carbohydrates, lipids, proteins, and nucleic acids.

What type of molecule is polymerized to form a carbohydrate?

Monosaccharides.

What type of molecule is polymerized to form a nucleic acid?

Nucleotides.

What type of molecule is polymerized to form a protein?

Amino acids.

A polymer of amino acids forms what type of macromolecule?

A protein.

How many types of amino acids may be found in a protein?

20.

What type of covalent bond links amino acids together in a protein?

Peptide bonds.

A polymer of 3 or more monosaccharides forms what type of carbohydrate?

A polysaccharide.

List an example of a polysaccharide.

Starch.

List an example of a monosaccharide.

Glucose.

A polymer of 2 monosaccharides forms what type of carbohydrate?

A disaccharide.

List an example of a disaccharide.

Sucrose.

A polymer of nucleotides forms what type of macromolecule?

A nucleic acid.

List two examples of nucleic acids.

DNA and RNA.

What does DNA stand for?

Deoxyribonucleic acid.

What does RNA stand for?

Ribonucleic acid.

List the 4 types of nucleotides found in DNA.

Adenine, thymine, cytosine, and guanine.

List a couple examples of lipids.

Fats, oils, and steroids.

What organic molecules would you suspect a compound called "lipopolysaccharide" is primarily composed of?

Lipids and carbohydrates (polysaccharides).