(LE1) Cell Biology Flashcards
Nucleus; Prokaryote vs. Eukaryote
P: no nucleus. Contain nucleoid region
E: Yes
Membrane bound organelles; Prokaryote vs. Eukaryote
P: No
E: Yes
Ribosomes; Prokaryote vs. Eukaryote
P: yes, 70s ribosome
E: yes, 80s ribosome
Chromosome structure; Prokaryote vs. Eukaryote
P: 1 circular piece
E: Variable (linear, singular, histones, etc.)
Cell wall; Prokaryote vs. Eukaryote
P: Yes, peptidoglycan
E: varies (animals;no cell wall, plants; cellulose, fungi; chitin)
Cell division; Prokaryote vs. Eukaryote
P: mitosis
E: mitosis or meiosis - sexual/asexual - clonal/recombinant
What are the magic bullet targets for bacteria characteristics?
Ribosomes, chromosome structure, and cell wall
Where do prokaryotes make ATP?
In cell membrane (no mitochondria)
Name this morphology
Coccus
Name this morphology
Vibrio
Name this morphology
Bacillus
Name this morphology
Spirillum
Name this morphology
Spirochete
Name this arrangement
Diplo
- Diplococci
Name this arrangement
Staphylo
- Staphylococci
Name this arrangement
Strepto
- streptococci
Name this arrangement
Tetrad
What arrangements are only applicable to cocci morphologies?
Tetrad and Staphylo
What is pleomorphic?
Capable of changing shape
What is the name of the indicated appendage? What is its function?
Flagella - used for motility in response to chemotaxis
What is the name of the indicated appendage? What is its function?
Axial filament - used for motility
Found in spirochetes
What do prokaryotes use for attachment?
Fimbriae and pili
What is the function of fimbriae?
Attachment to surfaces and other cells
- fine, hairlike bristles
What is the function of pilus?
Used for attachment and conjugation (exchange of genetic information)
- rigid tubular structure
What are plasmids?
Small circular extrachromosomal pieces of DNA. Not necessary for survival, but can give prokaryotes selective advantages: antibiotic resistance, toxins, alternative energy source
What are the two types of glycocalyx?
Capsule: organized molecules, thick layer
Slime layer: less organized, thin layer
What are the functions of the glycocalyx?
- adherence and mucoid (make biofilms)
- Phagocytosis protection
- resists dehydration and starvation
- protects from environment (antibiotics, chemicals, etc.)
How does the glycocalyx provide phagocytosis protection?
- Reduces recognition
- reduces ingestion
- reduces digestion
What is a bioflim?
microbial community with a shared slime layer
What are the benefits of biofilm?
- allows all bacteria to share nutrients
- sheltered from environment
- prevent dessication
- protected from host immune system
- helps with conjugation
What are the most common capsule forming pathogens?
Some Killers Have Pretty Nice Capsules
Streptococcus pneumoniae
Klebsiella pneumoniae
Haemophilus influenzae
Pseudomonas influenzae
Neisseria meningitidis/gonorrhoheae
Cryptococcus
Streptococcus pneumoniae causes…
pneumonia
Klebsiella pneumoniae causes…
pneumonia and bladder infections
Haemophilus influenzae causes…
meningitis and pneumonia
Pseudomonas influenzae causes…
cystic fibrosis. Common in burn pts
Neisseria meningitidis/gonorrhoheae causes…
meningitis or gonorrhea
Cryptococcus causes…
Is a fungus. Meningitis or fatal lung infections (AIDS pts).
What is the function of bacterial cell wall? What are its qualities?
prevent osmotic lysis and protects the cell membrane
- strong and protective
- non-selective
What are cell walls made of in 95% of bacteria?
Peptidoglycan: carbohydrate backbones held together by peptide cross-bridge links
Describe Gram+ cell walls
Thick layer of peptidoglycan (strong/nonselective)
- contain teichoic acid and lipoteichoic acid to attach peptidoglycan to cell membrane.
- acids give cell wall a negative charge
Describe Gram- cell walls
Thin layer of peptidoglycan and outer plasma membrane (not strong, but extremely selective)
- contains outer plasma membrane containing lipopolysaccharide (LPS)
- LPS is an endotoxin
- LPS gives cell wall a negative charge
What color does G+ stain? G-?
G+ = purple stain
G- = pink stain
Describe acid-fast cell wall
Waxy, lipoidal
- mostly composed of mycolic acid
- resistant to chemicals (antibiotics, disinfectants)
- Long-lived (resists desiccation and phagocytosis)
What bacteria contains an acid-fast cell wall?
All Mycobacterium. Ex/ Mycobacterium tuberculosis
How does the plasma membrane create a semipermeable barrier?
Phospholipid bilayer has polar head and non-polar tails.
- small hydrocarbons an nonpolar, small molecules like CO2 and O2 pass through
- Charged ions and large molecules like glucose, Na+, and amino acids don’t pass through
What are functions of integral protein in the plasma membrane?
act as channel proteins (aquaporin), carrier, etc.
What are some functions of peripheral proteins in the plasma membrane?
cell recognition, signal transduction, etc
Describe simple diffusion
molecules move from an area of high concentration to an area of lower concentration.
- no energy is required
What is tonicity?
Measure of solute concentration outside the cell; ability of a solution to cause a cell to gain or lose water
What would happen to a cell placed in a hypertonic solution?
plasmolysis: cell membrane shrivels up due to loss of water to hypertonic solution
What would happen to a cell placed in a hypotonic solution?
cytolysis: cell membrane swells up due to absorption of water from hypotonic solution
What is facilitated diffusion?
difussion with the help of protein. No ATP used, but still requires molecule-specific channel proteins or carrier proteins
What is active transport?
Molecules moved against their concentration gradient. Requires a protein and ATP
ex/ sodium/potassium pump
What is cytoplasm
Fluid interior of the cell
- contains dissolved nutrients, wastes, polymers gases, etc.
- contains cytoskeleton
Where do prokaryotic cells carry genetic information?
in the nucleoid region of the cytoplasm
Describe bacterial chromosome
- haploid (one copy)
- circular
- 1000s of genes
- No histones (not bound to anything. free floating in cytoplasm)
What’s an example of a deadly plasmid
E. coli O157:H7 contains the Shiga toxin on plasmid
What is the function of ribosomes?
Used for protein production
composed of 2 subunits: one small and one large
What’s the size difference between prokaryotic and eukaryotic ribosomes?
Prokaryotes: 70S (50S + 30S)
Eukaryotes: 80S (60S + 40S)
What are endospores?
Keratin structures that contain genetic material and some proteins. Remain dormant to survive adverse conditions
Which prokaryotes are endospores unique to? What are their oxygen requirements?
Bacillus - aerobic
Clostridium - anaerobic
What are the differences in a eukaryotic cell compared to a prokaryotic cell?
- usually bigger
- membrane bound organelles
- ATP made in mitochondria
- DNA in nucleus
- majority of protein made in rough E.R.
- no or different cell wall
What is endosymbiotic theory?
Mitochondria and chloroplasts evolved from symbiotic prokaryotes living within eukaryotes
What evidence do we have for endosymbiotic theory from weakest to greatest?
Mitochondria:
- same size as bacteria (1-2 microns)
- self-replicating
- own DNA (mDNA) circular
- double membrane
- own ribosomes (70S) (rRNA sequence closer to prokaryotes than eukaryotes)
