[MPARA LEC MIDTERMS] TO2

Prokaryotic Cell

Cell lacking a membrane-bound nucleus and membrane-bound organelles, generally containing one circular chromosome

Eukaryotic Cell

Cell containing a membrane-bound nucleus, membrane-bound organelles, paired chromosomes, and a mitotic spindle

Prokaryote

Organism with a non-membrane-bound nucleoid, no membrane-bound organelles, and generally one circular chromosome

Eukaryote

Organism whose chromosomes are enclosed within a nuclear membrane

Nucleoid

Non-membrane-bound region of a prokaryotic cell containing its chromosome

Nuclear Membrane

Membrane surrounding chromosomes in a eukaryotic cell

Prokaryotic Chromosome

Usually one circular chromosome that is not enclosed by a membrane

Eukaryotic Chromosomes

Paired chromosomes located within a nuclear membrane

Histones

Proteins associated with eukaryotic chromosomes that are absent from the typical prokaryotic chromosome comparison

Binary Fission

Cell division method used by prokaryotes

Mitotic Spindle

Structure involved in chromosome separation during eukaryotic cell division

Peptidoglycan

Material forming the cell wall of bacteria

Polysaccharide

Cell wall type associated with eukaryotic plants, algae, and fungi

Bacterial Cell

Prokaryotic cell containing a nucleoid, plasma membrane, cell wall, and ribosomes

0.2-1um wide, 2-8um long

Typical dimensions of bacteria

Coccus

Spherical bacterial shape

Bacillus

Rod-shaped bacterial shape

Vibrio

Curved or comma-shaped bacterial shape

Spirillum

Rigid spiral-shaped bacterial shape

Spirochete

Flexible, tightly coiled spiral-shaped bacterial shape

Monomorphic

Condition in which bacterial cells maintain a relatively consistent shape

Pleomorphic

Condition in which bacterial cells can vary considerably in shape

Stella

Star-shaped microbial form

Haloarcula

Square-shaped archaeal form

Diplococci

Cocci arranged in pairs

Staphylococci

Cocci arranged in clusters

Streptococci

Cocci arranged in chains

Diplobacilli

Bacilli arranged in pairs

Streptobacilli

Bacilli arranged in chains

Plasma Membrane

Selective barrier surrounding the cell that controls movement of substances into and out of the cell

Phospholipid Bilayer

Double layer of phospholipids forming the basic structure of the plasma membrane

Integral Protein

Protein embedded within the plasma membrane

Peripheral Protein

Protein associated with the surface of the plasma membrane rather than spanning it

Transmembrane Protein

Integral membrane protein that spans across the plasma membrane

Sterol

Lipid found in some plasma membranes that contributes to membrane properties

Chromatophore

Folded membrane structure containing photosynthetic pigments in certain prokaryotic cells

Thylakoid

Membrane structure containing photosynthetic pigments

Cell Wall

Structure outside the plasma membrane that provides support and prevents osmotic lysis

Osmotic Lysis

Rupture of a cell caused by excessive water entry when the cell wall cannot withstand osmotic pressure; due to hypotonic solution in some cases.

N-acetylglucosamine and N-acetylmuramic acid

polymers that make up the peptidoglycan and are linked by polypeptides

Peptide Bridges

Polypeptide links connecting peptidoglycan chains

Lysozyme

Enzyme that digests the disaccharide component of peptidoglycan

Penicillin

Antibiotic that inhibits formation of peptide bridges in peptidoglycan

Spheroplast

Wall-less bacterial cell

Protoplast

Wall-less Gram-positive cell according to the lecture

L Forms

Wall-less bacterial cells that swell into irregular shapes

Gram-Positive Cell Wall

Cell wall with thick peptidoglycan and teichoic acids

Gram-Negative Cell Wall

Cell wall with thin peptidoglycan, no teichoic acids, and an outer membrane

Teichoic Acids

Gram-positive wall components that may regulate cation movement and contribute to antigenic variation

Lipoteichoic Acid

Teichoic acid linked to the plasma membrane

Wall Teichoic Acid

Teichoic acid linked to peptidoglycan

Mycolic Acid

Lipid found in the cell wall of acid-fast cells

Acid-Fast Cell

Cell characterized by a cell wall containing mycolic acid

Periplasm

Region between the Gram-negative outer membrane and plasma membrane

Lipopolysaccharide

Outer membrane component containing lipid and polysaccharide portions and associated with endotoxin activity

Lipid A

Lipid portion of LPS that functions as an endotoxin

Endotoxin

Toxic component of Gram-negative LPS associated with Lipid A

O Polysaccharide

Polysaccharide portion of LPS that acts as an antigen and can identify bacterial strains

Porins

Proteins in the Gram-negative outer membrane that form channels

Protects bacteria from phagocytes, complement, and antibiotics

Gram-Negative Outer Membrane Function

E. coli O157:H7

Example of a bacterium identified using an O polysaccharide antigen and H antigen

Glycocalyx

Sticky extracellular material outside the cell wall that assists attachment and can protect against phagocytosis

Capsule

Organized and usually tightly attached form of glycocalyx

Slime Layer

Unorganized and loose form of glycocalyx

T

Capsule function t or f: Helps cells attach and prevents phagocytosis

Fimbriae

Short bacterial external structures primarily used for attachment

Pili

Bacterial external structures used to transfer DNA between cells

Flagellum

Long bacterial external structure used for motility

Flagellin

Protein forming the chains that make up the bacterial flagellar filament

Flagellar Hook

Protein structure connecting the flagellar filament to the basal body

Basal Body

Structure anchoring the flagellum to the cell wall and membrane

Flagellar Filament

External portion of the bacterial flagellum made of flagellin

Run

Bacterial movement produced by flagellar rotation that moves the cell forward

Tumble

Bacterial movement involving a change in direction

Taxis

Movement of a microorganism toward or away from a stimulus

Chemotaxis

Movement toward or away from a chemical stimulus

H Antigen

Antigen associated with bacterial flagellar proteins

Monotrichous

Flagellar arrangement with a single flagellum at one pole

Amphitrichous

Flagellar arrangement with flagella at both poles

Lophotrichous

Flagellar arrangement with a tuft of flagella at one pole

Peritrichous

Flagellar arrangement with flagella distributed over the entire cell surface

Axial Filament

Internal motility structure of spirochetes, also called an endoflagellum

Endoflagella

Flagella located within the periplasmic space of spirochetes

Endospore

Highly resistant resting bacterial cell structure resistant to desiccation, heat, and chemicals

Sporulation

Process of forming an endospore

Germination

Process by which an endospore returns to the vegetative state

Bacillus and Clostridium

Endospore are formed by these 2 bacteria

Vegetative Cell

Normal actively growing state of a bacterial cell

Mycoplasma

Bacterium lacking a cell wall and containing sterols in its plasma membrane

Pseudomurein

Archaeal wall material lacking N-acetylmuramic acid and D-amino acids

Nucleus

Eukaryotic membrane-bound organelle containing chromosomes

Endoplasmic Reticulum

Membrane-bound transport network within a eukaryotic cell

Golgi Complex

Organelle involved in membrane formation and secretion

Lysosome

Membrane-bound organelle containing digestive enzymes

Vacuole

Membrane-bound structure that brings food into cells and provides support

Mitochondrion

Organelle responsible for cellular respiration

Chloroplast

Organelle responsible for photosynthesis

Peroxisome

Organelle involved in oxidation of fatty acids and destruction of hydrogen peroxide

Hydrogen Peroxide h2o2

Reactive substance destroyed by peroxisomes

Ribosome

Cellular structure responsible for protein synthesis