Bio 1 exam ferris

Microbe (Microorganism)

An organism or infectious agent too small to be seen easily without a microscope.

Cell

The basic unit of life; contains a membrane, genetic material, cytoplasm, and metabolic capability.

Prokaryote

A cell lacking a nucleus; includes Bacteria and Archaea.

Eukaryote

A cell containing a nucleus and membrane-bound organelles.

Three Domains of Life

Bacteria, Archaea, and Eukarya.

Domains containing prokaryotes

Bacteria and Archaea.

Domain containing eukaryotes

Eukarya.

Metabolism

All chemical reactions that occur within a cell or organism.

Pathogen

An organism or agent capable of causing disease.

Microbiota

The microorganisms that normally live in a particular environment, such as the human body.

Taxonomy

The science of naming and classifying organisms.

Genus vs. Species in scientific naming

Genus is the first (capitalized) part of a scientific name; species is the second (lowercase) part.

Antonie van Leeuwenhoek

First scientist to observe and describe microorganisms using self-designed microscopes.

Edward Jenner

Developed the first successful vaccine against smallpox.

Louis Pasteur

Supported germ theory, showed microorganisms cause fermentation, and developed pasteurization and vaccines.

Joseph Lister

Applied germ theory to surgery and promoted antiseptic techniques.

Robert Koch

Developed postulates connecting specific microbes to specific diseases.

Alexander Fleming

Discovered penicillin.

Carl Woese

Proposed the Three-Domain system using molecular/rRNA evidence.

Estimated time microbes have existed on Earth

At least $\sim 3.5$ billion years.

Microbial habitats

Essentially everywhere: soil, water, air, humans, animals, and extreme environments.

Beneficial roles of microbes for humans

Digestion, vitamin production, immune development, food production, and biotechnology.

Binomial nomenclature

Two-part scientific naming system consisting of Genus + species.

Rules for writing scientific names

Genus capitalized, species lowercase; both italicized (or underlined if handwritten).

Hierarchy of taxonomic levels

Domain $\rightarrow$ Phylum $\rightarrow$ Class $\rightarrow$ Order $\rightarrow$ Family $\rightarrow$ Genus $\rightarrow$ Species.

Cellular status of viruses

Viruses are acellular (not composed of cells).

Presence of ribosomes in viruses

No, viruses lack ribosomes.

Metabolic capability of viruses

No, viruses do not have their own metabolism.

Viral reproduction capability

No; they require a host cell to reproduce.

Obligate intracellular pathogen

An organism or agent that must live and reproduce inside a host cell.

Cellular components lacking in viruses

Cellular membrane/cytoplasm, ribosomes, independent metabolism, and cellular machinery.

Structural components of a virus

Nucleic acid surrounded by a protein capsid; some also possess a lipid envelope.

Six most abundant elements in biology (CHNOPS)

Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur.

Atom

Smallest unit of an element that retains its chemical properties.

Proton

Positively charged subatomic particle located in the atomic nucleus.

Neutron

Uncharged (neutral) subatomic particle located in the atomic nucleus.

Electron

Negatively charged subatomic particle orbiting around the atomic nucleus.

Atomic nucleus

Central core of an atom containing protons and neutrons.

Electron shell

Region surrounding the nucleus where electrons are distributed.

Atomic number

The number of protons in an atom's nucleus.

Atomic mass

Approximately the sum of protons and neutrons in an atom.

Element

Substance made of atoms that all have the same atomic number (number of protons).

Molecule

Two or more atoms held together by chemical bonds.

Compound

Substance containing two or more different elements chemically bonded.

Ionic bond

Chemical attraction between oppositely charged ions following electron transfer.

Covalent bond

Chemical bond formed when atoms share electrons.

Hydrogen bond

Weak electrostatic attraction involving a partially positive hydrogen atom and a partially negative atom.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Effect of gaining electrons on atomic charge

The atom becomes negatively charged (an anion).

Effect of losing electrons on atomic charge

The atom becomes positively charged (a cation).

Effect of changing proton count in an atom

It turns into a different chemical element.

Polar covalent bond

Covalent bond where electrons are shared unequally between atoms.

Nonpolar covalent bond

Covalent bond where electrons are shared equally between atoms.

Cause of water's polarity

Oxygen attracts shared electrons more strongly than hydrogen, creating partial negative and positive charges.

Charge state of oxygen in water

Partial negative charge ($\delta^-$).

Charge state of hydrogen in water

Partial positive charge ($\delta^+$).

Hydrophilic

"Water-loving"; readily interacts with or dissolves in water.

Hydrophobic

"Water-fearing"; nonpolar substances that do not mix well with water.

Amphipathic

Possessing both hydrophilic and hydrophobic regions.

Acidic pH range

pH value below $7$.

Neutral pH value

pH value equal to $7$.

Basic (alkaline) pH range

pH value above $7$.

Relationship between $H^+$ concentration and pH

Higher $H^+$ concentration results in lower pH; lower $H^+$ concentration results in higher pH.

Four major biological macromolecules

Carbohydrates, lipids, proteins, and nucleic acids.

Monomer of carbohydrates

Monosaccharide.

Polysaccharide

Carbohydrate polymer composed of many linked monosaccharides.

Main components of a phospholipid

Glycerol, two fatty acid tails, and a phosphate group.

Monomer of proteins

Amino acid.

Monomer of nucleic acids

Nucleotide.

Two primary types of nucleic acids

DNA and RNA.

Primary function of DNA

Stores genetic information.

Primary function of RNA

Helps convert genetic information into proteins.

Elements in carbohydrates

Carbon, Hydrogen, Oxygen ($C, H, O$).

Elements in proteins

Carbon, Hydrogen, Oxygen, Nitrogen ($C, H, O, N$); sometimes Sulfur ($S$).

Elements in nucleic acids

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus ($C, H, O, N, P$).

Elements in lipids

Mainly Carbon and Hydrogen ($C, H$), with Oxygen ($O$) also present.

Coccus (plural: cocci)

Spherical bacterial cell shape.

Bacillus (plural: bacilli)

Rod-shaped bacterial cell.

Vibrio

Comma-shaped/curved bacterial cell.

Spirillum (plural: spirilla)

Rigid spiral-shaped bacterial cell.

Spirochete

Flexible, thin spiral-shaped bacterial cell.

Strepto- (bacterial prefix)

Arrangement of bacterial cells in chains.

Staphylo- (bacterial prefix)

Arrangement of bacterial cells in clusters.

Cell envelope

Structures surrounding the bacterial cytoplasm, including the cell membrane and cell wall.

Peptidoglycan

Rigid polymer lattice that provides structural strength to bacterial cell walls.

NAG and NAM

N-acetylglucosamine and N-acetylmuramic acid; alternating sugar backbones of peptidoglycan.

Gram-positive cell wall

Thick peptidoglycan layer containing teichoic and lipoteichoic acids.

Gram-negative cell envelope

Thin peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharide (LPS).

Teichoic acid

Polyalcohol polymers embedded within Gram-positive cell walls.

Lipoteichoic acid

Teichoic acid anchored directly into the plasma membrane of Gram-positive bacteria.

Lipopolysaccharide (LPS)

Outer membrane molecule of Gram-negative bacteria containing O-antigen, core polysaccharide, and Lipid A.

Lipid A

Toxic lipid component of LPS responsible for endotoxin activity.

Endotoxin

Toxin released upon bacterial lysis, specifically associated with Lipid A of Gram-negative LPS.

Porins

Protein channels in Gram-negative outer membranes enabling selective transport of solutes.

Acid-fast cell wall

Cell wall rich in waxy mycolic acids resistant to standard Gram staining.

Mycobacterium

Bacterial genus characterized by acid-fast cell walls containing mycolic acids.

Penicillin

Beta-lactam antibiotic that inhibits bacterial cell-wall peptidoglycan synthesis.

Lysozyme

Enzyme that cleaves glycosidic bonds in peptidoglycan, destroying bacterial cell walls.

Cell membrane (plasma membrane)

Phospholipid bilayer regulating passage of substances in/out of the cell.