Functional Anatomy of Prokaryotic and Eukaryotic Cells Flashcards
What are some common features of Prokaryotic and Eukaryotic Cells?
- Both have DNA and Chromosomes
- Both have cell membrane
- Both have cytosol and ribosomes
What are some characteristics which differentiate Prokaryotic and Eukaryotic cells?
- Types of Ribosomes
- Prokaryotic 70S ribosomes
- Eukaryotic 80S ribosomes
2. Nucleus
- Pro- nucleoid
- Euk- nucleus
3. Membrane Bound Organelles
- Only Euks. have them
4. Size - Pros. are smaller 0.2-2 micrometers
5. Cell wall
- Not all Euk. have them
6. Chromosomes
- Pros. large circular loop of DNA
- Euks. Linear chromosomes
Describe the chromosomes of Prokaryotes.
One circular chromosome, not membrane bound
Does the DNA of Prokaryotes contain histones?
No
Do prokaryotes contain membrane bound organelles?
No
Peptidoglycan cell walls
are found in both gram positive and negative bacteria
Prokaryotes reproduce by
Binary Fission
How does binary fission happen?
- The cell grows larger
- The cell copies its DNA
- The cell divides
What are histones?
proteins that DNA are wrapped around
monomorphic
one uniform shape
Pleomorphic
not all the same shape
Describe the size and shape of bacilli
- Rod shaped
- 2-8 micrometers long
- 0.2-1.0 micrometers wide
- singular: bacillus
Describe the size and shape of cocci
- 1-2 micrometers diameter
- Spherical
- singular: coccus
what is the average size of prokaryotes?
0.2-1.0 micrometers x 2-8 micrometers
What are the 3 basic shapes of bacteria?
- Bacillus (bacilli)
- Coccus (cocci)
- Spirals (Vibrio, spirillum, spirochete)
what are the types of spiral bacteria?
- Vibrio
- Spirillum
- Spirochete
most bacteria are _________ in apperance but some are _____________.
- monomorphic
- pleomorphic
Vibrio
spirillum
spirochete
What is an example of a Virbrio bacterium?
- Vibrio cholerae
- Causes severe watery diarreha
- A victim can lose up to 5 liters of fluid a day
what is another shape of bacteria?
- Coccobacillus
- shapped like a cocci and bacilli
what cellular arrangement is this?
- diplococci
- two cocci attached to eachother
what cellular arrangement is this?
- streptococci
- cocci in a chain formation
what cellular arrangement is this?
- Tetrad
- devide once in a perpendicular
What cellular arrangement is this?
- Sarcinae
- tetrad stacked
what cellular arrangement is this?
- Staphylococci
- clustered togther
what cellular arrangement is this?
- single bacillus
what cellular arrangement is this?
- diplobacilli
- two bacilli attached togther
what cellular arrangement is this?
- streptobacilli
- bacilli in a chain-like formation
what cellular arrangement is this?
- coccobacilli
- has characteristics of bacillus coccus bacteria
What type of bacteria are an example of pleomorphic?
- Corynebacteria; a dangerous bacteria
Cell arrangement
how the cells exist togther
Why is understanding cellular arrangement important?
Arragement can provide clues to what organism is causing a disease.
Known as a sugar coating, its made of sugar and protein, it forms a capsule around bacteria.
- Glycocalyx
Flagella
- long appendiages responsible for cell motility
- anchored to the cell wall and membrane
- number and placement determines if atrichous, monotrichous, lophotrichous, amphitrichous, peritrichous.
Axial filaments
- The central filament of a flagellum or cilium. Also called axoneme .
- Endoflagella- flagella inside the bacteria
- Found in spirochetes
- Anchored at one end of the cell
- Rotation causes cell to move
In what order should these go?
- Membrane
- Capsule
- Cell wall
- Capsule
- Cell wall
- Membrane
Fimbria (fimbriae)
- A fimbria (plural fimbriae) is a Latin word that literally means “fringe.”
- an appendage composed of curlin proteins that can be found on many Gram-negative and some Gram-positive bacteria that is thinner and shorter than a flagellum.
- Fimbriae are used by bacteria to adhere to one another and to adhere to animal cells and some inanimate objects.
Pilus (pili)
- A pilus (Latin for ‘hair’; plural : pili) is a hairlike appendage found on the surface of many bacteria. The terms pilus and fimbria (Latin for ‘fringe’; plural: fimbriae) can be used interchangeably, although some researchers reserve the term pilus for the appendage required for bacterial conjugation (sex).
- used to transfer DNA from one bacteria to another.
A. Chromosome (nucleoid)
B. Pilus
C. Ribosomes
D. Inclusion
E. Flagellum
F. Plasmid
G. Cytoplasm
H. Plasma membrane
I. Cell wall
J. Capsule or slime layer
Biofilm
- layer or a congragation of pathogens (bacteria)
- Can be found on implants or in foley catheters
Why are bacterial glycocalicies biologically important?
- Capsules can be considered a virulence factor
- Allows bacteria to scoot away from phagocytes
- Allows cells to attach to eachother and create biofilms.
Virulence factor
characteristics that cause bacteria to be harmful
Glycocalyx
- many bacteria secrete external surface layer composed of sticky polysaccharides, polypeptide, or both.
What are the 2 types of glycocaylices?
- Capsule: organized and firmly attached to cell wall.
- Slime Layer: unorganized and loosely attached.
Which bacteria is atrichous?
- A
- No flagella
What bacteria is monotrichous?
- B
- One flagellum
What bacteria is lophotrichous?
- D
- Many at one end
What bacteria is amphitrichous?
- C
- Flagella on both ends
which bacterium is peritrichous?
- E
- flagella all around
Flagella have a _______ and a ___________ in the membrane.
- motor
- drive shaft
what allows bacteria with flagella to move?
- rotation of the flagella
Why do the flagella of bacteria cause problems in humans?
- Because they trigger an immune response (H antigen)
- Flagella proteins are H-antigens -induce immune response.
- Escherichia coli O157:H7 Seventh position on flagella.
What is the flagella’s mechanism of rotation?
run and tumble
what is the movement of a bacterium toward or away from a stimuli?
Taxis
What are types of taxes?
- Chemotaxis
- Phototaxis
- Magnetotaxis
Bacteria movement: “Run”
- when bacteria move in one direction
Bacteria movement: “Tumble”
- When bacteria stop and change direction
run and tumble
- No taxis (no attractant or repellent)
- cell moves randomly
- Chemotaxis
- Bacterium moves toward an attractant (stimulus)
- arrow; Gradient of attractant concentration
Bacterial Conjugation
All bacteria have a cell wall but,
composition of the wall will vary from species to species.
Cells prefer ___________ solutions.
- isotonic
- Same amount of solutes inside and outside the cell.
cell lysis
- plasma membrane breaks apart
- cell walls in bacteria help to protect against osmotic lysis because they are firm and do not allow the plasma membrane to overfill.
NAG and NAM are __________
monomers
Cell walls are _________ to help bacteria keep __________ and _________ them.
- Rigid
- shape
- protect them
What does the cell wall consist of?
- Peptidoglycan- polymer of 2 monosacharride subunits covalently bondedtogther (NAG and NAM)
- NAG and NAM are linked by polypeptides (forming peptide cross bridges) with Tetrapeptide side chain attached to NAM (peptide bonds)
What are cell walls permeable to?
- ions
- amino acids
- sugars
- Gram positive cell walls may regulate movement of cations.
a. structure of peptidoglycan in gram positive bacteria.
A. NAG
B. NAM
C. Peptide bond
D. Side- chain amino acid
E. Cross-bridge amino acid
F. Tetrapeptide side chain
G. Peptide cross-bridge
H. Carbohydrate “backbone”
I. Site where penicilin breaks down bonds
Gram positive bacteria also have __________.
techicoic acid
A. Wall teichoic acid
B. Cell wall
C. Plasma membrane
D. Protein
E. Peptidoglycan
F. Lipoteichoic acid
G. Granular layer
who came up with gram staining?
- Hans Christian Gram
- based it on structure of their cell walls
What are teichoic acids in gram positive cell walls for?
- Lipoteichoic acid- links to plasma membrane
- Wall teichoic acid- links to peptidoglycan
- Helps to link peptidoglycan layers to cell membrane.
Gram positive cell walls…
- may regulate movement of cations
- Polysaccharides provide antigenic variation
Gram negative bacteria have ________ _________
- 2 membranes
Gram negative cell walls have ____________ which are toxic to humans.
Lipopolysacharrides (LPS)
what are the differences between Gram positive and gram negative cells?
- Gram positive
- Thick layer of peptidoglycaan
- Negatively charged teichoic acid on surface- links peptidoglycan to membrane.
- Gram negative
- Thin peptidoglycan
- Outer membrane with lipopolysaccharide
- Lipid A protein on surface- Lipid A is a lipid component of an endotoxin held responsible for the toxicity of gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide (LPS), also called endotoxin molecule, and its hydrophobicnature allows it to anchor the LPS to the outer membrane.[2] While its toxic effects can be damaging, the sensing of lipid A by the human immune system may also be critical for the onset of immune responses to gram-negative infection, and for the subsequent successful fight against the infection.[3]
Lipid A of LPS
- acts as an endotoxin on gram negative bacteria
O Polysaccharides
- antigens used for typing e.g, E. coli O157:H7
- O157 is the lipopolysaccharide antigen.
why do’t you want to kill gram - bacteria, how do you stop a gram negative bacterial infection?
- Lipid A will endotoxin will be released
- Interfere with gram - binary fission to cure gram - infection to lower bacteria numbers and allow immune system to take over.
Gram negative bacteria are __________ to medication.
- less sensitive to medication due to their outer membrane which does not allow medication into the cell.
LPS
outer layer of the outer membrane of a gram negative bacterium- Lipopolysaccharide
What type of cell wall is this? Name the structures.
- Gram negative
A. O polysaccharide
B. Core polysaccharide
C. Lipid A
D. Parts of the LPS
E. Porin protein
F. Phospholipid
G. Lipoprotein
H. Protein
I. Lipopolysaccharide
J. Cell wall
K. Outer membrane
L. NAG
M. NAM
N. Peptidoglycan
O. Plasma membrane
P. Periplasm (protein rich gel-like fluid)
Are all bacteria ether gram negative or positive?
No there are other kinds of bacteria that are not gram positive or negative.
What happens to Gram-positive bacteria when you stain them?
- Alcohol dehydrates peptidoglycan
- CV-I (crystal violet/ iodine) crystals do not wash away (leaves the cell wall with a purple color)
What happens to Gram-negative bacteria when you stain them?
- The alcohol dissolves outer memrane and leaves holes in peptidoglycan
- CV-I washes out
- Safranin is used as a counter stain; the gram negative cellstake up the dye giving them a red/pink apperance.
Does safranin only stain gram-negative cells?
No, grampositive cells take up dye too but they are so saturated with CV-I crystals that they still appear purple.
How do you preform a gram stain?
- Take a slide, mix specimen and apply a thin layer of specimen on slide.
- Apply CV; CV stains all the cells
- Apply iodine- CV-I react to form precipitate (crystals) form inside cells
- Rinse or decolorize cells with acetone or acetone alcohol.
- Quick rinse with water to get rid of acetone
- Apply safranin (counterstain)
- rinse slide with water again and let dry
Which cells are gram positive and which are gram negative?
- Purple cells are gram positive
- Pink cells are gram negative
Which macromolecule (s) contain nitrogen?
- Proteins
- Nucleic acids (nitrogenous bases)
What is the term for extra chromosomal DNA?
Plasmid
Mycoplasmas
- Have no cell wall
- they have a cell membrane which has cholesterol compounds in it (sterols; similar to eukaryotic cells)
- Cannot be detected by typical light microscopy.
- Pleomorphic- because no cell wall
why does the gram stain not work on mycoplasmas?
- they have no cell wall
- gram stain doesn’t work on bacteria with no cell wall.
Which genera have acid-fast cell walls?
- Mycobacterium
- Nocardia
what is unique about acid-fast cell walls?
- they contain mycolic acid (waxy lipid) covers thin peptidoglycan layer
- they do not stain well with gram stain
- they require an acid-fast stain which penetrates their mycolic acid cell walls and colors the cytoplasm.
- Carbol fushin is the stain; it washes out of other bacteria which do not have mycolic acid.
when preforming an acid fast stain non-acid fast ___________ ___________ are added to the sample.
- Control bacteria
acid fast stain steps
Acid-Fast Stain - Steps
- Carbol Fuchsin - 10-15 minutes (rinse)
- Acid Alcohol - 3-5 seconds (rinse)
- Methylene Blue - 2 minutes (rinse)
- Blot slide dry gently with bibulous paper
what bacteria is this what is its shape? Why?
- mycoplasmas
- pleomorphic
- it has no cell wall only a plasma membrane with sterols (cholesterol compounds)
What type of cell wall is this?
What kind of bacteria have this wall?
- Acid-fast cell wall
- Mycobacteria and Nocardia
A. Lipoarabinomannan
B. Mycolic acid
C. Arabinogalactan
D. Peptidoglycan
E. Mannophosphoinositide
F. Plasma membrane
Which bacteria is acid fast stained? Which is the control?
- A is the control (Staphylococcus epidermidis) because it is blue; stained by methlyene blue
- B is the acid fast stained one (Mycobacterium gordonae) because it is stained fuschia by carbol fushin
Lysozyme
- a chemical that digests disaccharide (NAG and NAM) in peptidoglycan
- a component of lysol
- mostly effective on gram positive bacteria which depend on their cell walls for protection.
How does penicillin work?
- it inhibits peptide bridges in peptidoglycan
- it stops the formation of peptide bridges in peptidoglycan by binding to an enzyme that aids in the construction of cell walls.
- the enzyme can no longer aid in peptide bond formation, so the cell cannot reproduce, it undergoes osmotic lysis
- most effective with gram positive
Bacteria do not have mitochondria how do they make ATP?
- in their membrane
- the plasma membrane of bacteria play a part in energy transformation (electron transport chain for ATP production.)
What features do both prokaryotic and Eukaryotic cells have in common?
- phospholipid bilayer with proteins (fluid mosaic model)
- Permeability barrier (selectively permeable)
- Both use diffusion, osmosis and transtport proteins
Damage to the membrane by alcohols, quaternary ammonium (detergents), and polymyxin antibiotics causes _______________.
leakage of cell contents
antigen
An antigen is any substance that causes your immune system to produce antibodies against it. An antigen may be a foreign substance from the environment, such as chemicals, bacteria, viruses, or pollen. An antigen may also be formed inside the body, as with bacterial toxins or tissue cells.
what part of the phospholipid bilayer is the barrier?
the hydrophobic tails
which part of protein channels are hydrophobic?
the middle, the protein is folded in a way which all the hydrophobic amino acids are at the center.
A. Lipid Bilayer of plasma membrane
B. Peptidoglycan
C. Outer membrane
D. Polar heads (hydrophilic phosphate group and glycerol)
E. Nonpolar tails (hydrophobic fatty acids)
F. Lipid bilayer
G. Pore
H. Peripheral protein
I. Integral proteins
J. Peripheral
K. Polar head
L. Non-polar fatty acid tails
M. Polar head
What do the integral proteins do?
- They allow for selective permeability
- Membrane channel proteins and other transport proteins
what are the types of diffusion?
- simple diffusion
- facilitated diffusion
- osmosis
How do molecules get through a semipermeable membrane?
- Passive transport; simple diffusion, facilitated diffusion, osmosis
- Active transport; pumps, enocytosis, exocytosis
Isotonic
same amt of solutes inside and out the cell
Hypertonic
more solutes outside of the cell than inside of the cell
Hypotonic
Less solutes outside of the cell than inside of the cell
What kind of ribosomes do prokaryotes have? What are the componets of that ribosome?
- 70S ribosomes
- Made of a 30S subunit and a 50S subunit
- 30,50,70
- All odd #s
What kind of ribosomes do eukaryotes have? What are their components?
- 80S ribosomes
- 40S subunit and a 60S subunit
- 40,60,80
- All even #s
where do most biochemical activities occur?
the cytoplasm and internal structures
Nucleoid
nuclear region containing DNA up to 3500 genes
Plasmids
small, nonessential, circular DNA (5-100) genes; replicate independently.
Inclusion bodies
granules containing nutrients, monomers, Fe compounds (magnetosomes)
plasmids are important because
- they can contain genes for antibiotic resistance
bacteria pick up or exchange plasmids
- with other microbes
- in the enviornment
why are the differences in ribosomes between Euk. and Pro. important?
the differences in ribosomes allows us to treat bacterial diseases with minimal side effects to the patient.
Is the plasmid also replecated in binary fission?
- yes
- plasmids can also replecate on their own
why is it detergents such as the ones used to wash hands disrupt the cell walls of bacteria but do not cause our skin to fall apart?
- our skin contains hydrophobic keratin which protects live cells
- stem cells quickly make more skin cells
- Bleach is harmful becaues it crosses the barrier and causes damage to live cells
Endospores
- Dormant, tough, non-reproductive structure
- they germinate
- they have a vegetative form
Endospores are resistant to
- UV
- radiation
- dessication
- lysozyme
- temperature
- starvation
- chemical disinfectants
Endospores make disease caused by their bacteria
hard to treat
Germination
when endospores return to their (actively growing) vegetative state.
what are the 2 spore forming genera?
- Clostridium
- Bacillus
A. Sporulation; the process of endospore formation
B. Bacterial chromosome (DNA)
C. Plasma membrane
D. Cell wall
E. Cytoplasm
F. Spore septum begins to isolate newly replicated DNA and a small portion of the cytoplasm
G. Plasma membrane starts to surround DNA, cytoplasm and membrane isolated in step F
H. Spore septum surrounds isolated portionforming fore spore
I. 2 membranes
J. peptidoglycan layer forms between 2 membranes
K. spore coat forms
L. endospore is freed from cell
during sporulation the DNA of the bacteria moves to
- ether end of the bacteria
which structures are spores and which are vegetative cells?
- Green; spores
- Pink; vegetative
A. Vacuole
B. Cell wall
C. Chloroplast
D. Peroxisome
E. Nucleus
F. Nucleolus
G. Rough endoplasmic reticulum
H. Smooth endoplasmic reteiulum
I. Microtubule
J. Microfilament
K. Mitochondrion
L. Plasma membrane
M. Ribosomes
N. Cytoplasm
O. Golgi complex
P. Basal body
Q. Flagellum
R. Lysosome- contains lysozyme
S. Centrosome; centriole, pericentriolar material
