biol205~ exam #1

Raj Nathaniel

Domain

The highest level in biological classification:

• Bacteria

• Archaea

• Eukarya

Eukaryote

Organism composed of one or more eukaryotic cells; members of the domain Eukarya.

Eukaryotic Cell

Cell type characterized by a membrane-bound nucleus.

Prion

An acellular infectious agent consisting only of protein.

Prokaryote

Single-celled organism consisting of a prokaryote cell; members of the domains Bacteria and Archaea.

Prokaryotic Cell

Cell type characterized by the lack of membrane-bound nucleus.

Viroid

An acellular infectious agent consisting only of RNA.

Microbe

General term encompassing microorganisms and acellular infectious agents such as viruses.

Spontaneous Generation

Discredited belief that organisms can arise from non-living matter.

Biogenesis

The production of living things from other living things, as opposed to spontaneous generation.

Ferdinand Cohn

Discovered endospores.

Endospores

An extraordinarily resistant dormant cell produced by some types of bacteria (heat-resistant).

Germ Theory of Disease

Idea that infectious diseases are caused by microorganisms.

Normal microbiota

The group of microorganisms that colonize the body surfaces but do not usually cause disease.

Microbiome

The community of microorganisms, as well as their genetic information, in a given environment.

Commercial benefits of microorganisms

Microbes make life more comfortable for humans:

• Food production (Bread, beer, wine, cheese, yogurt, buttermilk, sauerkraut, pickles, etc.)

• Biodegradation of environmental pollutants (clean water and soil)

• Produce valuable products (hydrogen, ethanol, oils, antibiotics, etc.)

• Biotechnology (genetic engineering)

Pathogen

Disease-causing microbe.

Emerging infectious diseases (EIDs)

New diseases and diseases increasing in incidence or geographic range.

Genus

Taxonomic category of related organisms, usually containing several species. The first name of an organism in the Binomial System of Nomenclature (capitalized).

Species

A group of closely related strains; the basic unit of taxonomy (not capitalized).

Strain

A pure culture isolate; genetic variant within a species.

Bacteria

Single-celled prokaryotes:

• rigid cell walls that contain peptidoglycan

• move using flagella

Coccus

A spherical cell that may be flattened on one end or slightly oval.

Rod or bacillus

A cylindrical cell. One short enough to be confused with a coccus is called a coccobacillus.

Vibrio

A short, curved rod.

Spirillum

A curved rod long enough to form spirals.

Spirochete

A long, spiral-shaped cell with a flexible cell wall and a unique mechanism of motility.

Plemorphic

Not an actual shape, but refers to bacteria that characteristically vary in their shape.

Diplococcus

A pair of cocci.

Eukarya

Include fungi, algae, protozoa, and helminths (worms).

Protist

A eukaryotic organism other than a plant, animal, or fungus; may be unicellular or multicellular.

Fungi

Heterotrophic eukaryotic organisms containing chitin in the cell wall.

Mycelium

A densely branched network of the hyphae of a fungus.

Algae

Eukaryotic photosynthetic organisms with relatively simple reproductive structures and no organized vascular spasms.

Protozoa

Heterotrophic unicellular eukaryotic organisms that are not fungi:

• do not have a rigid cell wall

Helminths

Worms; often have complex life cycles.

Virus

An acellular infectious agent consisting of nucleic acid surrounded by a protein coat.

Viroid

An infectious agent of plants that consists only of RNA.

Atom

The basic unit of matter.

Buffer

A chemical that stabilizes the pH of a solution.

Covalent Bond

A chemical bond formed when two atoms share electrons.

Hydrogen Bond

The attraction between a hydrogen atom in a polar molecule and an electronegative atom in the same or another polar molecule.

Ion

An atom or molecule that has gained or lost one or more electrons.

Ionic Bond

A chemical bond resulting from the attraction between positively and negatively charged ions.

Molecule

Two or more atoms held together by covalent bonds.

Nucleic Acid

A macromolecule consisting of one or two nucleotide chains; DNA or RNA.

Organic Compound

A compound that has a carbon atom covalently bonded to a hydrogen atom.

pH

A measure of the hydrogen ion concentration or acidity of a solution on a scale of 0-14.

Protein

A macromolecule consisting of one or more chains of amino acids.

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur

The 6 most common elements in biology.

Lewis Symbol

Uses the element symbol and indicates the number of valence electrons using dots.

Electrolytes

Salts that conduct electricity when dissolved in water.

Non-polar covalent bond

Bond formed by sharing electrons between atoms that have equal attraction for the electrons.

Polar covalent bond

Bond formed by sharing electrons between atoms that have unequal attraction for the electrons.

Mole

Amount of a chemical in grams that contains 6.022 x 10^23 particles.

Molarity

The number of moles of a compound dissolved in enough water to make 1 liter of solution.

Synthesis reactions

These combine two or more reactants to form a larger product.

Decomposition reactions

These split a reactant into one or more smaller products.

Exchange reactions

These couple synthesis and decomposition to trade one or more components of the reactants; as one bond is broken, another is formed.

When a base is added, the concentration of H+ ___________.

Decreases

When an acid is added, the concentration of H+ in the solution __________.

Increases

Macromolecule

A very large molecule usually consisting of repeating subunits.

Polymer

Large molecule formed by the joining together of repeating small molecules (subunits).

Monomer

Subunit of a polymer.

The four major classes of organic molecules:

Carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Monosaccharides; structural component of cell walls; energy source.

Lipids

Subunits are not always similar; some types are important components of cell membranes; energy storage.

Proteins

Amino acids; enzyme catalysts; structural portion of many cell components.

DNA

Deoxyribonucleotides; carrier of genetic information.

RNA

Ribonucleotides; various roles in protein synthesis; catalysis.

Dehydration synthesis

Chemical reaction in which H2O is removed with the result that two molecules are joined together.

Hydrolysis

Chemical reaction in which a molecule is broke down as H2O is added.

Carbohydrates

An organic compound composed of one or more simple sugars.

Monosaccharide

A simple sugar; the basic unit of a carbohydrate.

Disaccharide

Carbohydrate molecule consisting of two monosaccharide molecules.

Polysaccharide

Large molecule composed of many monosaccharide subunits.

Lipid

An organic molecule that is not soluble in water.

Fatty acids

Linear carbon skeletons with a carboxyl group (--COOH) at one end.

Saturated fatty acid

Contain no double bonds between carbon atoms; they have the maximum number of hydrogen atoms.

Unsaturated fatty acid

Contain one or more double bonds between carbon atoms.

Simple lipid

Contain only carbon, hydrogen, and oxygen.

Triglyceride

Molecule consisting of three molecules of the same or different fatty acids bonded to glycerol.

Steroid

Type of lipid with a specific four-membered ring structure.

Polypeptide

Chain of amino acids joined by peptide bonds; also called a protein.

The amino acids in a chain are joined together by covalent bonds called ______.

Peptide bonds

Primary structure

Refers to the sequence of amino acids in a protein.

Secondary structure

Refers to a repeated folding or coiling in a localized region of a protein; the two major arrangements are helices and sheets.

Tertiary structure

The overall three-dimensional shape of a folded protein resulting largely from the interactions of R groups on amino acids.

Quaternary structure

Level of structure or a protein molecule consisting of several polypeptide chains.

Molecular chaperone

Protein that helps other proteins fold properly.

Denature

Disrupt the three-dimensional structure of a protein molecule; separate the complementary strands of DNA.

Adenine and Guanine

Nucleobases that are purines; double-ring structure.

Cytosine, Thymine, and Uracil

Nucleobases that are pyrimidines; single-ring structure.

Capsule

A distinct, thick gelatinous material that surrounds some microorganisms.

Chemotaxis

Movement of a cell toward or away from a certain chemical in the environment.

Flagellum

A type of structure used for cell movement.

Gram-Negative bacteria

Bacteria that have a cell wall characterized by a thin layer of peptidoglycan surrounded by an outer membrane; when Gram stained, these cells are pink.

Gram-Positive bacteria

Bacteria that have a cell wall characterized by a thick layer of peptidoglycan; when Gram stained, these cells are purple.

Lipopolysaccharide (LPS)

Molecule that makes up the outer layer of the outer membrane of Gram-negative bacteria.

Peptidoglycan

A macromolecule that provides strength to the cell wall; it is found only in bacteria.