Lecture 3 Flashcards
What are characteristics of prokaryotes?
No nucleus
Genome- one circular chromosome
No membrane-enclosed organelles
Complex cell walls- peptidoglycan
Divide by binary fission
What are characteristics of eukaryotes?
Nucleus
Genome- multiple paired chromosomes
Membrane enclosed organelles- mitochondria, golgi complex
Simple cell walls (if present)- chitin, cellulose
Divide by mitosis
What are the shapes of prokaryotic cells?
Bacillus- rod shaped
Coccus- spherical
Spiral- corkscrew
How are prokaryotes arranged?
Single
Pairs- diplococci, diplobacilli
Clusters- staphylococci
Chains- streptococci, streptobacilli
What is glycocalyx?
Sugar coat outside of cell wall
Exist in prokaryotes
What are the 2 types of glycocalyx?
Capsule- organized, firmly attached, prevents phagocytosis
Slime layer- not organized, loosely attached, facilitates adherence (biofilms)
What are fimbriae?
Exist in the prokaryotic cell
Short protein filaments in surface
Adherence/colonization- biofilms, epithelial surfaces
What is chemotaxis?
Organism movement toward/away from stimuli
Chemical
What is phototaxis?
Organism movement toward/away from from stimuli
Light
What are prokaryotic means of motility?
Flagella, pili, endoflagella
What does peritrichous mean?
Over entire cell
Prokaryotic
What does monotrichous mean?
One at one pole
Prokaryotic flagella
What does lophotrichous mean?
Prokaryotic flagella
Tuft at one pole
What does amphitrichous mean?
At both poles
Prokaryotic flagella
What are the 2 forms of flagella movement in prokaryotes?
Propellers-rotate
Run and tumble- peritrichous characteristic, movement in one direction (run), abrupt, random changes in direction (tumble)
What are axial filaments (endoflagella)?
Fibril bunches under outer sheath
Anchored at ends
Spiral motion entire organism
Spirochetes (syphilis, Lyme disease)
What are pili?
Means of motility in prokaryotes
Few per cell
Can pull bacteria forward along surface like grabbing hook
Twitching motility (short, intermittent jerky motions)
What are the means of motility in eukaryotic cells?
Flagella
Cilia
Pseudopodia (pseudopod)
How are flagella characterized in eukaryotes?
Few, long
Undulate (wave, whip-like)
Glide smoothly
How are cilia characterized in eukaryotes?
Numerous
Short
Oar-like
How are pseudopodia characterized in eukaryotes?
False feet
Extensions of cytoplasm
What does the bacterial cell wall do?
Surrounds plasma membrane
Protects cell from adverse changes in outside environment
Made of peptidogylcan (like a lattice)
What is peptidogylcan made of?
Disaccharide (sugar backbone) NAG-NAM
Polypeptides- side chains off NAMS; cross bridges connect side chains (penicillin blocks bridge formation)
What are gram positive bacterial cell walls made up of?
Many layers of peptidogylcan
Contain teichoic acid linked to peptidogylcan
Lipoteichoic acid linked to plasma membrane; passage of ions through wall
What are gram negative cell walls made up of?
One/few layers of peptidogylcan
What makes up the outer membrane of gram negative cell walls?
Phospholipids, integral proteins, lipopolysaccarhide (LPS) and porins (channels)
What does the outer membrane of gram negative cell walls do?
Immune invasion (mimicry)
Protective barrier (ex: antibiotics)
What do lysozymes do and what are examples of it?
Digests peptidoglycan disaccharide
Tears, saliva, mucus
What does penicillin-sensitive antibiotics do to the bacterial cell wall?
Prevents peptidoglycan cross bridge formation
What does the outer membrane do for bacteria in terms of antibiotic invasion?
It’s partially lysozyme resistant
Penicillin-resistant
Cephalosporins generate (which penetrate and block peptidoglycan synthesis)
What are endospores?
Resting cells
Survival in adverse environments
What is sporulation?
Endospore formation (genome and most essential proteins)
What are endospores resistant to?
Desiccation, heat, chemicals, radiation
What is the structure of the plasma membrane?
Phospholipid bilayer
Peripheral proteins
Integral proteins
Where are peripheral proteins found in the plasma membrane?
Inner/outer surface
Enzymes are scaffolding
Where are integral proteins in the plasma membrane?
Embedded (ex: channels)
What does the fluid mosaic model say?
Proteins move to function
What are the functions of the plasma membrane universally?
Selectively permeable barrier
Small molecules pass like water, oxygen, carbon dioxide
Large molecules don’t (proteins)
What does the plasma membrane do in prokaryotes?
Site of ATP production (no mitochondria)
Site of photosynthesis (no chloroplasts)
What does the plasma membrane do in eukaryotes?
Phagocytosis- cellular eating
Pinocytosis- membrane folds inward, bringing in fluid and dissolved substances (cellular drinking)
What is simple diffusion?
Solutes move freely (ie oxygen)
What is facilitated diffusion?
Solute moves with the help of transporter protein
Non specific or specific
What kind of molecules use active transport?
Sodium, potassium, calcium, chlorine
Large molecules: amino acids and simple sugars
What is group translocation?
Only happens in prokaryotes
Substance is chemically altered during transport so it can’t leave
ex: glucose
What are the major structures in prokaryotes?
Nucleoid
Plasmids
Ribosomes
What is the nucleoid?
Region where genome is located
Prokaryote
What are plasmids?
Circular, extrachromosomal DNA
Antibiotic resistance, toxin, enzymes
What do ribosomes do in prokaryotes?
Sites of protein synthesis
What are the major structures in eukaryotic cytoplasm?
Cytoskeleton
Nucleus
Ribosomes
Membrane- bound organelles- lysosomes, mitochondria, golgi complex, rough and smooth ER
What is the cytoskeleton?
In eukaryotic cells
Internal structure of proteins- support and shape, cell movement, movement of substances inside
What is the structure of prokaryotic ribosomes?
RNA + protein
30S+50S=70 S
What is the structure of eukaryotic ribosomes?
60S+80S=80S
What are antibiotic targets?
30S- streptomycin and gentamycin
50S- erythromycin and chloramphenicol
What are the evidences of eukaryotic evolution?
Resemble bacteria shape and size
Contain circular DNA
Reproduce independently of host cell by binary fission
70S ribosomes
Double-membraned as if engulfed
