Lecture 3 Flashcards by Sarah Mortimer

What are characteristics of prokaryotes?

No nucleus

Genome- one circular chromosome

No membrane-enclosed organelles

Complex cell walls- peptidoglycan

Divide by binary fission

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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

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What are the shapes of prokaryotic cells?

Bacillus- rod shaped

Coccus- spherical

Spiral- corkscrew

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How are prokaryotes arranged?

Single

Pairs- diplococci, diplobacilli

Clusters- staphylococci

Chains- streptococci, streptobacilli

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What is glycocalyx?

Sugar coat outside of cell wall

Exist in prokaryotes

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What are the 2 types of glycocalyx?

Capsule- organized, firmly attached, prevents phagocytosis

Slime layer- not organized, loosely attached, facilitates adherence (biofilms)

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What are fimbriae?

Exist in the prokaryotic cell

Short protein filaments in surface

Adherence/colonization- biofilms, epithelial surfaces

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What is chemotaxis?

Organism movement toward/away from stimuli

Chemical

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What is phototaxis?

Organism movement toward/away from from stimuli

Light

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What are prokaryotic means of motility?

Flagella, pili, endoflagella

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What does peritrichous mean?

Over entire cell

Prokaryotic

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What does monotrichous mean?

One at one pole

Prokaryotic flagella

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What does lophotrichous mean?

Prokaryotic flagella

Tuft at one pole

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What does amphitrichous mean?

At both poles

Prokaryotic flagella

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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)

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What are axial filaments (endoflagella)?

Fibril bunches under outer sheath

Anchored at ends

Spiral motion entire organism

Spirochetes (syphilis, Lyme disease)

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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)

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What are the means of motility in eukaryotic cells?

Flagella

Cilia

Pseudopodia (pseudopod)

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How are flagella characterized in eukaryotes?

Few, long

Undulate (wave, whip-like)

Glide smoothly

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How are cilia characterized in eukaryotes?

Numerous
Short

Oar-like

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How are pseudopodia characterized in eukaryotes?

False feet

Extensions of cytoplasm

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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