Prokaryotes: Bacteria 09/04/18 Flashcards
What are the two types of Prokaryotes?
Bacteria and Archaea
What are the two main differences between Bacteria and Archaea?
- How they package their DNA
2. How they contain their internal structures
What are the two most common forms of bacteria?
- Coccus (sphere shape)
2. Bacillus (rod shape)
What are the less common forms of bacteria?
- Coccobacillus
- vibrio
- spiralla
- spirochete
- pleomorphic
What are the terms for a coccus pair? A chain? A cluster?
Pair- diplo
chain- strep
cluster- staph
What are the terms for a bacillus pair? A chain? A cluster?
Pair- diplo
Chain- Strep
Cluster- Palisades
What are the layers of the bacterial cell envelope?
- capsule or slime layer (outermost)
- Cell wall (middle)
- Plasma membrane (innermost)
What are the types of proteins found in the plasma membrane (Cell envelope)?
- Integral proteins
2. peripheral proteins
Give a brief description on integral proteins.
embedded in membrane, insoluble
Give a brief description on peripheral proteins.
Loosely connected to membrane, soluble
What are the jobs of integral proteins?
A. Transportation in and out of the cell
B. Energy processes: ETC
C. Interact with environment
How does temperature affect membrane fluidity?
Warmer temps increase fluidity; colder temps decrease fluidity
More _________ fatty acid portion of phospholipid maintains fluidity in cold temp by preventing tight packing in bilayer
Unsaturated
Microbes that prefer high temps are?
Longer and more saturated
Microbes that prefer lower temperatures are?
shorter and unsaturated
**How does the membrane transport “things” in and out of the cell?
the membrane is selectively permeable (know this)
What are the types of transport?
A. Passive B. Facilitated C. Active D. Group translocation E. Iron intake
a) What are main features of passive transport (diffusion)?
b) What types of molecules can undergo passive transport?
A. Molecules move based on concentration gradient at a rate based upon the difference between the concentrations
B. Only gases and non-charged molecules
What are main features of Facilitated diffusion?
A. Molecules move with assistance from transport proteins.
B. Channel proteins, Carrier (Uniport) proteins, very specific
C. Still diffusion which means no energy
What is the main feature(s) of active transport?
Uses energy to transport molecules against the gradient.
What is the difference between primary active transport and secondary active transport?
Primary active transport uses ATP to move molecules
Secondary active transport uses energy from ION down gradient
What is the function of Antiporters?
one molecule moves out while another molecule comes in
What is the function of Symporters
two different molecules move in the same direction
a) What are the main features of Group translocation?
b) What type of transport is it considered?
A. molecule is chemically modified when moved into the cell by carrier proteins
B.active transport
An example of this would be E. Coli which transports sugars like glucose, fructose, mannitol, sucrose.
This creates a one-way street
What is the main feature of Iron uptake?
Extermely important for bacteria, but iron is not very soluble so very little available.
What are Siderophores and what is their role in Iron uptake?
They are molecules released by bacteria, bind iron, and bring it back to the cell to be released or use ABC transporter
What are the jobs of the cell wall?
A. Maintains Cell shape
B. protection from lysis(rupturing of the cell)
C. protection from toxic substances
D. contributes to pathogenicity (causing disease in humans)
**The cell wall is the target of many antibiotics
What happens when the osmotic pressure inside the cell is less than the outside?
It would be a hypertonic solution and the cell would undergo Plasmolysis
What happens when the solution inside the cell has more osmotic pressure than the outside?
It would be a hypotonic solution and the cell would undergo Osmotic lysis (rupture of the cell)
What happens when the osmotic pressure inside the cell is equal to the pressure outside the cell
It would be an isotonic solution and nothing would happen
What is peptidoglycan? (In the cell wall)
What subunits are found in it?
Mesh like structure found in all bacterial cell walls; consists of repeating subunits: NAG, NAM, & oligopeptides
- they are strong, elastic, porous
- **penicillin targets this structure
What are lipopolysaccharides and where are they found?
In the cell wall
They are only found in gram negative bacteria.
- Consists of three parts: O-antigen, core polysaccharide, Lipid A
- Protects bacteria from host defenses and acts as a potent endotoxin
- When released, causes septic shock
What are Porins and where are they found? (In the cell wall)
Found in only gram negative bacteria
- form channels across cell wall
- allows small molecules to enter the periplasm
What is Teichoic Acid and where is it found? (In cell wall)
Found only in gram POSITIVE bacteria
-aid in cell shape, division, and antimicrobial resistance
How to identify Gram positive and negative
Positive is purple; negative is pink Step 1 = crystal violet (Primary stain) Step 2 = Iodine (Mordant) Step 3 = Alcohol (de-colorizer) Step 4 = Safranin (Counterstain)
What are the similarities between gram positive and gram negative? ***
A. Periphrastic Space
B. PPG
C. Plasma membrane
What are some things that gram positive feature that gram negative doesn’t?
Teichoic Acid, Exotoxins, Antibiotic susceptible
What are some things that gram negative feature that gram positve doesn’t?
Outer membranes
- LPS
- Porins
- Endotoxins
- Antibiotic resistant
