Prokaryotes

knwo the different cell shapes.

coccus, bacillus, spiral,

• unusual shapes = Streptomyces and Walbsy’s square bacterium

Be able to diagram correctly the structure of prokaryotes

include the plasma membrane, cell wall, glycolayx, flagella, fibrae, pilli, cytoplasm, inclusions, ribosomes, nuceloid, and the chromosome

What is the phospholipid bilayer and how does it protect the cell.

• hydrophilic head

• hydrophobic tail

• controls movement going in and out of the cell

Define glycolipid and glycoprotein. Where are they found

• glycolipid/ glycoproteins are proteins and lipids with carbohydrates attached to them

• found in a cell membrane

What is osmosis? What is diffusion?

osmosis = movement of water across a selective permeable cell memebrane

diffusion - things move form high concentration to low concentration

Passie and active transport

Passive = transports without energy

active = uses energy to transport agaisnt a concentration gradient

simple and facilitated diffusion

simple = small molecules like O and CO2 can pass

facilitated = proteins help molecules cross membrane

What is osmotic pressure and what cellular structure protects agaisnt it?

osmotic p = pressure to prevent inward flow of water across a semipermeable membrane

protects agaisnt the cell wall

• Gram Positive Cell Walls: 

• has a single thick layer of peptidoglycan and teichoic acid molecules

• Thick and rigid structure 

• Porous, will allow many types of very small molecules to pass through 

  • very strong 

Gram Negative Cell Walls: 

• A single thin layer of peptidoglycan 

• Surrounded by  an outer membrane or phospholipids and lipolysaccharides(LPS)

• Thin/ flexible structure 

• Has hydrophobic and hydrophilic barriers = less penetrable by small molecules 

What is LPS and why is it important to disease?  What is an endotoxin?

• LPS = fatty sugar

• important to disease because it is a potent activator in the immune system 

• endotoxin = lipid A; anchors 2 cell membrane 

  • if it gets into blood system it will shock immune system 

How does the Gram stain work?

1. Application of crystal violet = enters the cells with either type of cell wall 

2. Application of Iodine = causes the crystal violet to clump up and become inside the cells 

3. Alcohol Wash = decolorizes. washes away the crystal violet-iodine clumps 

   1. Crystal Violet will stick on too thick cells 

   2. also strips away the outer membrane of thin cell walls

4. Application of Safrain = counterstains and enters the thin cell 

Pink = Negative ; Purple = positive 

Describe the glycocalyx, differentiate between slime layer and capsules, and give examples of how it benefits cells.

• Glycocalyx = “ sugar Coat” 

  • A layer of polysaccharides (sugars) and proteins surrounding the outside of the cel

  • Slime Layer = disorganized and loosely attached 

    • cloudy of sticky carbo hydrates

• Capsules = Organized and firmly attached 

  • Protein and sugars 

• All often important for pathogenesis : 

  • attachment, protection form immune systems and formation of biofilms

  • Ex. Bacillus anthracis = causes teeth to decay after cavities 

Ex. Streptococcus mutans 

• BioFilms from activity form bacteria 

What is a biofilm?  Why are biofilms medically relevant?

• Biofilm = a community of microbes, like bacteria, that stick to a surface and form a protective, slimy layer made of a self-produced matrix

  • Medically relevant because they contribute to the persistent and recurrent infections including catheters. 

Diagram and explain the basic structure of flagella, and characterize how they rotate to generate cell movement.

• Structure of a Flagella: 

1. Filament = long, thin, helical structure composed of protein flagellin 

2. Hook = curved sheath 

3. Basal Body = stack of rings firmly anchored in cell wall 

• Rotates 360 degrees 

• Functions on motility of cell through environment 

 Describe fimbriae and pili and explain their function.

• Fimbriae = protein ‘bristles” that protrude from the cell surface 

  • Function: adhesion to surfaces and other cells

• Pili = rigid tubular structure made of Pilin protein 

  • found in negative gran cells only 

  • Funhction:  to join bacteria cells for partial DNA transfer called conjunction 

Define cytoplasm and describe its composition.

• Cytoplasm = everywhere inside the cell 

  • 80% water but also include proteins, carbohydrates and lipids 

  • Thick/ jelly-like form all the large molecules present 

  • Where most of the action is 

    • Like Jello 

- What is the nucleoid?  Differentiate between the chromosome and plasmids.

• Nucleoid = accounts for 20 percent of the cell’s mass, containing a variety of proteins but most importantly the: 

  • Chromosomes and Plasmids 

• Chromosome = Single circular, double stranded DNA molecule that contains all the genetic information required by a cell 

• Plasmids = Free small circular , double stranded DNA, not essential to bacterial growth. metabolism

  • Used in genetic engineering 

What are ribosomes?  What purpose do they serve?

• Ribosomes = Central Dogma of Biology 

  • Composed of rRNA and proteins

  • Protein synthesis = DNA (blue print)  → RNA(photocopy) → Protein(machine)  

  • Take DNA into action 

  • Required for a central process of life and are thus found in all living thighs 

  • Important target of antibodies 

    • Wtv happens to ribosomes = die 

What are endospores and what purpose do they serve?  Do all bacteria make endospores?

• Endospores =  hardy, dormant form that bacteria take on when the environment becomes unfavorable 

• Not all bacteria make endospores

Compare eukaryotic cell walls to bacterial.  Which eukaryotes have cell walls, and which ones don’t?  Which use chitin and which use cellulose.

• Eukaryotic Cells: 

  • made of carbohydrates: 

  • No peptidogvylcan sugar coat 

• Fungi, Plants, and some protist have eukaryotic cell walls 

• Chitin = fungi 

• Cellulose = plants 

• Bacteria Cell Walls: 

  • Mostly made of peptidoglycan 

  • Filled with sugars and amino acids 

Describe eukaryotic flagella and cilia, and explain their function.

• Both structurally the same

• used by specialized cells in multicellular organisms 

• Flagella = 

  • Few and long

  • Covered by cell membrane 

  • way thicker than prokaryotic flagella 

  • Fun = motility 

• Cilia = 

  • short and numerous 

  • Found only on a single group of protozoa and certain animal cells

  • Func = motility, feeding, and filtering 

What is the nucleus?  How do eukaryotic chromosomes differ from bacterial one?

• Nucleus: 

  • membrane-bound organelle in eukaryotic cells that contains the cell's genetic material (DNA)

  • Surrounded by 2 membranes 

  • contain the cell’s chromosomes 

  • Feature of eukaryotes 

• Eukaryotic Chormosones: 

  • Linear DNA Molecules 

  • More than one 

  • Much bigger: 

    • E. Coli 

    • H. spaiens

What is the purpose of mitosis?  In what groups of organisms does it occur?

• Mitosis = specialized cell division in eukaryotic cells 

• Bacteria, Archaea, and Eukaraya 

- What are organelles?  Briefly describe the function of chloroplasts, mitochondria, lysosomes, and vacuoles.

• Organelles = specialized membrane compartments inside the cell 

  • little organs 

• Chloroplasts = Gather energy  form sunlight where photosynthesis happens

• Mitochondria = cells powerhouse; only in eukaryotes

• Lysosomes = vesicles that contain enzymes form Golgi apparatus 

  • involved in intracellular digestion of food particles and in protection against invading microbes

• Vacuoles = Membrane bound sacs that contain particles to be digested, excretes, or stored

What is the endosymbiotic theory for the origin of mitochondria and chloroplasts?

• mitochondria and chloroplasts originated as free-living prokaryotic cells (aerobic bacteria for mitochondria and cyanobacteria for chloroplasts) that were engulfed by a larger, early eukaryotic cell