Chapter 4 Prokaryotic and Eukaryotic Cells

42 terms by ks46046 

Create a new folder

Advertisement Upgrade to remove ads

Functional Anatomy of Prokaryotic and Eukaryotic Cells

Word origins of Prokaryote and Eukaryote

Comes from the Greek words for prenucleus and true nucleus respectively.

Traits of Prokaryotes

One circular chromosome, not in a membrane; No histones, no organelles, Bacteria: peptidoglycan cell walls; Archaea: pseudomurein cell walls; binary fission

Traits of Eukaryotes

Paired chromoseds in a nuclear membrane; histones; organelles; polysaccharide cell walls; mitotic spindle

Traits of Prokaryotes

Average size of 0.2-1.0 micronmeters x 2-8 micrometers; monophorphic; a few pleomorphic

Basic Shapes of Prokaryotes

Bacillus(Rodlike); Coccus(spherical); Spiral(spirillum, vibrio, spirochete)

Three Arrangements of Bacteria

Pairs(diplocci, diplobacilli); Clusters(staphylococci); Chains(streptococci, streptobacilli)

Glycocalyx

Outside the cell wall usually sticky; capsule is neatly organized; has a slime layer that is unorganized and loose; extracellular polysaccharide allows cell to attach; capsules prevent phagocytosis

Flagella

Outside cell wall; made of chains of flagellin(protein) attached to a protein hook; anchored to the wall and membrane by the basal body

Motile Cells

Rotate flagella to run or tumble; move toward or away from stimuli(taxis); Flagella proteins are H antigens(antigen = anything that can fight an antibody)

Axial Filaments

Also called endoflagella; in spirochetes; anchored at one end of a cell; rotation causes cell to move

Fimbriae and Pili

Hollow tube like structures; Fimbriae used to attach to things; Pili are used to facilitate transfer of DNA from another cell and for gliding and twitching motility

Cell Wall

Prevents osmotic lysis(breaking down); made of peptidoglycan(in bacteria)

Composition of Peptidoglycan

Polymer of disaccharide: N-acetylglucosamine(NAG) and N-acetylmuramic acid(NAM)

Peptidoglycan in Gram-P Bacteria

Linked by polypeptides

Primary Characteristics of Gram-P Cell Wall

Thick peptidoglycan; Teichoic acids; 2 ring basal body; Disrupted by lysozyme(enzyme that disrupts pepidoglycan); Penicillin sensitive

Primary Characteristics of Gram-N Cell Wall

Thin peptidoglycan; Outer membrane; Periplasmic space; 4 ring basal body; Endotoxin; Tetracycline sensitive

Functions of Gram-P Cell Wall

Contains Teichoic Acids such as Lipoteichoic acid and links to plasma membrane also Wall teichoic acid links to peptidoglycan; Cell wall may regulate movement of cations; Polysaccharides provide antigenic variation

Gram-N Outer Membrane

Lipopolysaccharides, lipoproteins, phospholipids; Forms the periplasm(contains peptidoglycan layer) between the outer membrane and the plasma membrane;
Provides protection from phagocytes, complement(things body uses to kill) and antibiotics; O polysaccharide antigen, e.g. E. coli 0157:H7; Lipid A is an endotoxin; Porins(proteins) form channels through membrane

Gram stain mechanism

Crystal violet-iodine crystals form in cell; Gram-P has alcohol dehydrating peptidoglycan and CV-I crystals do not leave
Gram-N Alcohol dissolves outer membrane and leaves holes in peptidoglycan and CV-I washes out

Atypical Cell Wall Characteristics(Acid Fast)

Acid-fast cell walls like gram-p cell walls; waxy lipid(mycolic acid) bound to peptidoglycan; Mycobacterium(pathogen:leprocy) Nocardia

Atypical Cell Wall Characteristics(Mycoplasmas)

Lack cell walls and therefore pleomorphic and contains sterols in plasma membrane;

Atypical Cell Wall Characteristics(Archaea)

Wall-less or walls of pseudomurein (lack NAM and D-amino acids)

Cell Wall Damage

Lysozyme digests disaccharide in peptidoglycan; Penicillin inhibits bridges in peptidoglycan; Protoplast is a wall-less cell; Spheroplast is a wall-less gram-p cell. Both are susceptible to osmotic lysis; L forms are wall-less cells that swell into irregular shapes

Plasma membrane composition

Phospholipid bilayer; Peripheral proteins, Integral proteins; Transmembrane; Proteins; Sterols(Eukaryotes have most bacteria don't)
Glycocalyx carbohydrates

Fluid Mosaic Model

Membrane is as viscous as olive oil; Proteins move to function; phopholipids rotate and move laterally

Plasma membrane Functions

Selective permeability allows passage of some molecules; enzymes for ATP; Photosyntethic pigments on foldings called chromatophores or thylakoids
Simple and facilitative diffusion, Osmosis, Active Transport
Endocytosis both Phagocytosis(pseudopods extend and engulf particles) and Pinocytosis(membrane folds inward, bringing in fluid and dissolved substances)

Plasma membrane damage

Damage to the membrane by alcohols, quaternary ammonium(detergents), and polymyxin antibiotics causes leakage of cell contents

Movement of Materials across membranes

Simple diffusion: movement of a solute from high concentration to low;
Facilitated diffusion: solute combines with a transporter protein in the membrane(uses no energy goes through pore)
Osmosis: movement of water across a selectively permeable membrane from high concentration to low
Osmotic pressure: pressure needed to stop the movement of water across membrane
Movement goes through lipid layer and aquaporins(water channels)
Active Transport: requires a transporter protein and ATP(allows for low to high movement)
Group translocation: requires a transporter protein and PEP(moves more than one molecule at a time)

Isotonic

No net movement of water occurs

Hypotonic

Water movesinto the cell. If the cell wall is strong, it contains the swelling. If the cell wall is weak or damaged, the cell bursts (osmotic lysis).

Hypertonic

Water moves out of the cell, causing its cytoplasm to shrink (plasmolysis).

Cytoplasm

Substance inside plasma membrane but outside the nucleus
Cytosol: fluid portion of cytoplasm
Cytoskeleton: microfilaments, intermediate filaments, microtubles
Cytoplasmic streaming: movement of cytoplasm throughout cells

Nucleoid

Bacterial chromosome (DNA)

Prokaryotic Ribosome

Protein synthesis; 70S (sedimentation)50s/30s subunits

Inclusions

Metachromatic granules(volutin)-phosphate reserves
Polysaccharide granules-energy reserves
Lipid inclusions-energy reserves
Sulfur granules-energy reserves
Carboxysomes-Ribulose 1,5 diphosphate carboxylase for CO2 fixation
Gas vacuoles-protein-covered cylinders
Magnetosomes-iron oxide(destroys H2O2)

Endospores

Resting cells
Resistant to desiccation, heat, chemicals
Bacillus, Clostridium
Sporulation: endospore formation (survival mechanism)
Germination: return to vegetative state (normal ops)

Flagella and Cilia

Microtubules; made of Tubulin a protein; 9 pairs +2 array

Cell wall and glycocalyx

Cell wall are in plants, algae, fungi, carbohydrates
Composed of cellulose, chitin, glucan, mannan
Glycocalyx is made of carbohydrates extending from animal plasma membrane and bonded to proteins and lipids in membrane

Plasma membrane

Phospholipid bilayer
Peripheral proteins
Intergral proteins
Transmembrane proteins
Sterols(eukaryotes have most bacteria don't)
Glycocalyx carbohydrates

Ribosomes

Protein synthesis
80s (eukaryotes); membrane-bound attached to ER; free: in cytoplams
70s in chloroplasts and mitochondria

Organelles

Nucleus: contains chromosomes
ER: transport network
Glogi complex: membrane formation and secretion
Lysosome: digestive enzymes
Vacuole: brings food into cells and provides support
Mitochondrion: cellular respiration(ATP)
Chloraplast: photosynthesis
Peroxisome: oxidation of fatty acids; destroys(H2O2)
Centrosome: consists of protein fibers and centrioles

Endosymbiotic Theory

2 species living together 1 inside of the other

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set