Prokaryotic Cells Flashcards
What are prokaryotes? ( 6 identifications )
Unicellular organisms, no nuclear membrane, lack organelles, one circular dna with no histone, proteins, divide by binary fission, divide into 2 large groups called domain ( archae and bacteria )
Are all prokaryotes uniceullar?
Yes
Do prokaryotes have a nuclear membrane ?
No
What do prokaryotes lack
An organelle
Do prokaryotes have histones proteins ?
They do not
What type of dna does prokaryotes have ?
One circular dna with no histone
How does prokaryotes divide
Binary fission
What is binary fission?
Asexual, when organism splits into two identical organisms without sex
What two domains do prokaryotes fall under?
Bacteria and archaea
Are all bacteria prokaryotes ?
Yes
How are prokaryotes differentiated by (6)
Size, shape, arrangement, nutritional requirements, biochemical activies, staining characteristics
What are three basic bacterial shapes ?
Cocci ( circular ), bacillus ( bacilli ), spiral (spaghetti )
How can bacteria size and shape vary?
Through the availability of nutrients
What is the arrangement of bacteria ? ( coccus )
Single, diplococci, tetrad, sarcinae, streptococci, staphylococci
What is the arrangement of bacteria ( bacilli )?
Single, diplobaccili, coccibacilli
What is the arrangement of pairs in bacteria ?
Diplococci, diplobaccilli
What is the arrangement of clusters in bacteria
Staphylococci
What is the arrangement of chains in bacteria ?
Streptococci, streptobaccilli
What is vibrio, spirillum, spirochete apart of?
Bacterial shape, sprilla
Describe the shape of the 3 sprilla
Vibrio ( bean ), spirillum ( half noodle ), spirochete ( full noodle )
What is on the outside of a prokaryotic cell? (5 things)
Glycocalyx, flagella, axial filaments, fimbriae, pilli
What is the name of the cell wall in bacteria
Peptidoglycan
What is the name of the cell wall in archaea
Pseudomurein
Do all bacteria have a cell wall
No, but 90% do
What’s another name for cytoplasmic membrane
Plasma membrane
What’s inside of a prokaryotic cell? (6)
Cytoplasm, nuclear body ( nucleotid ) & plasmids, inclusions, ribosomes, Endospores
What is found in all bacteria (4)
Cytoplasm, ribosome, plasma membrane, nucleoid (containing dna )
What is glycocalyx?
Sticky, dense surface layer that surrounds the cell, containing CHO ( OUTSIDE OF THE CELL )
What is the function of glycocalyx? (3)
Virulence factor !
Attachment to surfaces, protection from phagocytosis by wbc
What is glycocalyx made up of ?
Polysaccharide, polypeptide or both
What is the function of phagocytosis ?
The destruction of bacterial cells by WBC
What is a virulence factor?
Disease causing, colonizing the hist at a cellular level
What are 2 types of glycocalyx in prokaryotes?
Capsule and slime layer?
What does capsule mean for glycocalyx in prokaryotic?
Organized & firmly attached
What does slime layer mean for glycocalyx in prokaryotic?
Unorganized & loosely attached
Are glycocalyx found in both gram positive (+) and gram negative (-) bacteria ?
Yes
What are biofilms?
A complex collection of microorganisms
How is a biofilm made?
Clump of cells that attach to each other & solid surfaces
What plays an important part to biofilms ?
Glycocalyxes, since they attach
What are glycocalyxes called in a biofilm ?
Extracellular polymeric surfaced (EPS)
What does extra cellular polymeric surfaces (EPS) do in biofilms (3)
Protect cells, communication, attachment to surfaces
Can biofilms be harmful and beneficial ?
Yes
Are bacteria in biofilms resistant?
Yes, and to antibiotics & becomes more virulent ( examples teeth, tongue, rocks )
What is the function of flagellum/flagella ?
Movement
Where is flagella/flagellum found ?
Outside the cell
What are taxis in flagella ? Define and examples
Taxies are movement towards and away from environment
Examples ; chemotaxis & photo taxis
Flagellum/flagella are only on what shape bacteria?
Rods, vibrios and sprilla
What are the three parts of a flagella/flagellum ?
Filament, hook, basal body
What does the fliament in flagella/flagellum do? (3)
Movement
Produce a protein called flagellin
Contains H antigen to distinguish various strains
What does the hook do in flagella/flagellum ?
Attachment point for filament
What does the basal body do in flagella ?
Anchors filament & hook to plasma membrane
How many rings in basal body flagella does gram positive (+) have?
2 rings
How many rings in basal body flagella does gram negative (-) have?
4 rings
What is flagella made up from?
Chains of flagellin
How does flagella move?
Clockwise or counterclockwise
Where are axial filaments found it?
Spirochetes, outside the cell
How does an axial filament move
Corkscrew or spiral motion
What’s another name for axial filaments ?
Endoflagella or inner flagella
Summary for endoflagella (axial filaments ) (2)
Flagella for spirochetes, move in a spiral motion(mobility)
What is fimbriae?
Hair like microfibrils & shorter than flagella
Where is fimbriae located?
Outside the cell
Where is fimbriae mainly found gram positive (+) or gram negative (-) ?
Gram negative (-)
What is the function of fimbriae?
Attachment/adhesion to cell surfaces, involved in forming biofilms
Is fimbriae a virulence factor
Yes
What protein does fimbriae and pili have?
Pilin
What is the function pili?
Sex pili, transfer of DNA from one cell to another cell ( joining of two bacterial cells together )
How many pili are in a bacterium?
1 or 2
Where is pili?
Outside of the cell
What is the function of a cell wall? (3)
Gives the shape, prevent rupturing of cell, protection of internal structures
How does the cell wall help flagella?
Site of attachment from basal body
Do all prokaryotes have a cell wall?
Almost, expect mycoplasma
Does gram negative (-) and gram positive (+) have a cell wall?
Yes
What’s the difference of cell wall in gram positive (+) and gram-negative (-)?
The composition and thickness
What type ( name of type ) of cell wall does gram-positive (+) and gram-negative (-) have?
Peptidoglycan
How many components does peptidoglycan (murein) have?
3
What’s the first component in peptidoglycan?
Alternating two amino acids
- NAM & NAG
What’s the name of NAG and NAM
Nag - N-acetylglucosamine
NAM - N-acetylmuramic acid
What’s the second component in peptidoglycan?
Tetrapeptide
Alternating D and L forms
Sub units of nam
What’s the third component in peptidoglycan?
Interpepride cross bridges
What does inter-peptide cross bridges do?
Provide strength and rigidity to peptidoglycan
What destroys interpeptide cross bridges?
Penicillin
How does a gram-positive (+)bacteria cell wall look like?
Thick
and undifferentiated layer that covers the cell membrane
What type of layers of gram-positive (+) have (2)
Peptidoglycan & teichoic acids
What is teichoic acids?
Linear polymers, covalently attached to the peptidoglycan
Can teichoic acids be found in gram positive (+)
Yes
What is lipoteicholic acids?
Covantely link to plasma membrane glyolipids
Can lipoteichoic acids be found in gram positive (+)?
Yes
How does gram negative (-) cell wall look like?
Thin peptidoglycan
What does a gram negative (-) consist of ? (2)
Lipopolysaccharide (LPS) & outer membrane
Does gram negative (-) have teicholic acids ?
No
What makes the peptidoglycan in gram negative (-) different from gram positive (+) ? (2)
Thinner and suspended periplasmic space
Where is the periplasmic space in gram negative (-)
Between the outer membrane & plasma membrane
Does gram-positive (+) have an outer membrane?
No
How many regions are in LPS ?( lipopolysaccharides) in gram negative (-) ?
3, lipids A, Core and O polysaccharide
What is the function of lipid A in LPS?
Induced fever & shock
What’s another name for lipid A
Endotoxin
What’s the function of core in LPS
Core polysaccharides provides structural stability
What’s the function of O polysaccharide in LPS
An “ O” antigen that distinguishes different species of gram negative (-) bacteria
What is the function of an outer membrane?
Barrier to environment ( against antibiotic and toxins )
Is an outer membrane in gram-negative (-)?
Yes
What are porins in the outer membrane of gram negative (-)?
Channels that allows certain substances to enter a cell in the outer membrane
What are the defense mechanism for the outer membrane ?
Evade phagocytes & complement
What’s the main difference between gram positive (+) and gram negative (-)?
Positive (2)
Negative (4)
Positive
Thick Peptiglyocan, trichoic acid
Negative
Thin peptidoglycan, outer membrane, LPS, periplasmic
What color is gram-positive (+)?
Purple
What color is gram-negative (-)?
Pink/red
What is the gram stain step?
Crystal violet, iodine, alcohol, safarin
What does alcohol do in gram-positive(+)? (2)
Dehydrates peptidoglycan & crystals stay
What does alcohol do in gram-negative(-)? (3)
Dissolves outer membrane
Leaves hole in peptidoglycan
Crystal leave
Does Mycoplasma have a cell wall?
No
Does Arcahae have a peptidoglycan wall?
No, instead has pseudomurein
Can archaea be gram stained ?
No
However can appear gram negative (-)
What is lysozymes
Enzymes that hydrolyzes NAM-NAG bond ( break down )
What are examples of lysozymes
Tears and salvia
Do all cells have a plasma membrane
Yes
What/how does plasma membrane enclose
Enclose Cytoplasm with fluid mosaic structure
Does cytoplasm have sterols?
No, expect mycoplasma
What is the cytoplasm made up of? (What layer)
Phospholipid bilayer + proteins
What is a phospholipid hydrophobic region?
Non polars, hates water, fatty acid tails
What is a phospholipid hydrophilic region
Polar heads, love water, glycerol + phosphate
What are the Two types of proteins inside a Plasma membrane
Integral ( embedded ) & peripheral ( loosely )
What does proteins do for cytoplasm?
Transport materials into cells
What does the fluid mosaic model contain? (7)
Phospholipid bilayer
Peripheral protein
Integral proteins
Transmembrane
Membrane that’s viscous (slippery)
Phospholipid moving laterally
Proteins transporting materials
What’s the plasma membrane functions? (4)
Carry enzymes for ATP
Transport molecules
Protects cytoplasm
Biosynthetic function
Since plasma membrane, transport proteins, what’s the most common?
Proteins that falicitate passive diffusion
What’s inside the plasma membrane? (6)
Cytoplasm, nucleoid, plasmids, ribosomes, inclusions & endospores
What’s the cytoplasm mainly made of ? (Weight or?)
80% water
What inside the cytoplasm ? (6)
Proteins, enzymes, CHO, lipids, DNA, ribosomes
What is a nucleoid in prokaryotes ?
DNA not surrounded by a cell membrane
Nucleoid contain how many chromosomes
1
How does a chromosome look like?
Double stranded, circular helical
Is there a histones in chromosomes?
No
What is a bacterial chromosome?
Molecule contain all or most DNA
How does plasmids look?
Extrachromosomal, DS, circular, DNA
What is the function of plasmids?
Produce copies of itself & transfer to another
Are plasmids need for survival?
No kinda makes them die more when it doesn’t carry ( replicating ) genes for resistance
What is the site that ribosomes promote?
Protein synthesis
What is the function of proteins synthesis?
Creation of polypeptide
What’s the complete ribosome count?
70s
What is the math to get the complete Ribosome count?
30s + 50s = 70s
What’s the s in 70s ribosome?
Svedberg units, sedimentation value
What’s the function of inclusions?
Accumulation of nutrients and using these nutrients when there isn’t enough in the environment
What are endospores
A survival mechanism
Why are endospores made ?
To survive in extreme climate or need
What are the names of endospores for gram positive (+ )
Clostridium & bacillus
What are the names of endospores for gram negative (-)
Coxiella Burnetti
What’s sporultaion?
Endospores formation ( not reproduction )
What’s germination ?
Endospores go back to normal
What’s germinate
Favorable conditions for endospores
