PROKARYOTIC CELLS

What are the primary shapes of bacteria cells?Examples of each?

*Round-coccus-(Staphylococcus aureus)

*Rod-Bacillus-(E. coli)

*Bent rod-Vibrio-(Vibrio cholera)

*Spiral-Spirillum-(helicobacter pylori)

*Corkscrew-spirochete-(treponema palidum)

What are the primary arrangements of bacteria cells?Examples of each?

*Single-scattered-(E.coli)

*Chain-strepto-(streptococcus pyogenes)

*Two-diplococcus-(streptococcus pneumonia)

*Cluster-staphylo-(Staphylococcus aureus)

*Chain-Streptobacilli

*Two-Diplobacilli

What are flagella made of? What do they do? Do all bacteria have them? Examples? How might theycontribute to disease?

*Complex structure made of protein

*Used for motility

*Helps bacteria move around

*Not all bacteria have them

monotrichous

single flagellum

Amphitrichous

flagella at both ends of the cell

Lophotrichous

cluster of flagella at one or both ends

Peritrichous

flagella all over

What are fimbriae made of? What do they do? Do all bacteria have them? Examples? How do theycontribute to disease?

*Protein filaments

*Used for attachment

*Ex: E. coli

*Not all bacteria have them

*Shorter than flagella

What are pili made of? What do they do? Do all bacteria have them? How do they contribute to disease?

*Protein tube

*Used for material exchange

*Allows bacteria to connect and exchange genetic instructions for antibiotic resistance

*Not all bacteria have them

What is the capsule made of? What does it do? Do all bacteria have one? Examples? How does the bacterialcapsule contribute to disease?

*Outer covering of cell primarily made of carbohydrate material (sticky sugar)

*Used for attachment

*Can form biofilms

*Ex: Streptococcus mutans (found on teeth

What is a biofilm? What bacterial cell structures can allow bacteria to form biofilms (one answer is given in thevideo - see if you can figure out another correct answer)?

*Thin layer of life formed on a surface

*Capsules allow biofilm formations

*Ex: Streptococcus mutans

What is a cell wall made of?

peptidoglycan

*Polymer of saccharides (NAG and NAM) cross linked by short amino acid chains

Why is the cell wall important?

It maintains the cells shape and prevents extra water uptake which could damage the cell.

What is peptidoglycan? What subunit molecules make up peptidoglycan?

Multiple parallel chains of alternating sugars

*NAG-(N-acetylglosamine)

*NAM-(N-acetylmuramic acid)

*Cross linked by amino acid chains

Why are peptidoglycan's amino acid crosslinks important to bacteria? In healthcare?

helps protect bacterial cells from environmental stress and helps preserve cell morphology

What is the structure of the Gram positive cell wall? Example?

*Thick layer of peptidoglycan surrounding the plasma membrane

*Ex: Streptococcus pyogenes, staph aureus

What is the structure of the Gram negative cell wall? Example?

*Thin layer of peptidoglycan sandwiched between plasma membranes

*Ex: E. coli

What is lysozyme? Why is it important to health?

*Catalyzes hydrolysis of of peptidoglycan

*Enzyme

*Weakens the cell wall

How does penicillin work?

inhibits cell wall synthesis

Why are waxy cell walls important medically? Example?

*Difficult to stain

*Can go undiagnosed because nothing is seen under the microscope

*Resistant to antibiotics

*Ex: Mycobacterium tuberculosis

What types of bacteria lack cell walls? Can any bacteria that lack cell walls cause disease?

*Mycoplasma species

*Can cause disease

*Very small

*Ex: Mycoplasma pneumoniae

What is the structure of the cytoplasmic membrane? Do all bacteria have a cytoplasmic membrane?

*Phospholipids arranged in a bilayer

*Not all bacteria have them

What are phospholipids?

Two fatty acids joined together

Why are phospholipids able to form bilayers?

Hydrophilic heads hydrophobic tails

What roles do proteins play in the cytoplasmic membrane?

*Transport

*Receptors

*Ligands

*Enzymes

What is a gradient? Examples?

An unequal distribution of something

ex) height, thermal, pressure, electrical, concentration

What is simple diffusion?

when molecules spread from an area of high to an area of low concentration

What are solutes?

what is being dissolved (salt)

what are solvents

does the dissolving (water)

What does it mean if a cell's cytoplasm is isotonic compared to the cell's surroundings?

*Ideal for cells

*Equal solute concentration inside and outside the cell

What does it mean if a cell's cytoplasm is hypotonic compared to the cell's surroundings?

Lower solute concentration inside the cell

What does it mean if a cell's cytoplasm is hypertonic compared to the cell's surroundings?

higher solute concentration inside the cell

Hypertonic environment

more "salt" outside, more water inside

Cell shrinks

hypotonic environment

more salt in the cell, water moves into the cell

*Cell lysis occurs

*Typical for bacteria

What is osmosis?

Diffusion of water through a selectively permeable membrane

What cell structure protects bacteria from rupturing due to osmosis?

cell wall

What is facilitated diffusion?

movement of a substance from areas of high concentration to areas of low concentration with the help of a transport protein (for large or polar substances)

Ex: Glucose, amino acids

*Passive (no energy required)

What is active transport? How does active transport relate to gradients across the cell membrane?

*Movement of a substance from areas of lower concentration to areas of higher concentration

*Goes against the gradient

*Requires energy and a pump

*Often used to create a gradient

*Gradients can store energy

What is an example of active transport?

proton pump

How are endocytosis and exocytosis similar? Different?

Endocytosis- movement of material into the cell

Exocytosis- movement of material out of the cell

What is cytoplasm? What is it mostly made of? Do all bacteria have cytoplasm?

*Cell fluid

*Mostly h2o with dissolved nutrients, enzymes, and other biomolecules

*All bacteria have cytoplasm

What are ribosomes? Do all bacteria have ribosomes?

*Site of protein synthesis

*Structurally different than eukaryotic ribosomes

*All bacteria have them

How do prokaryotic and eukaryotic ribosomes differ? Why is this important medically?

*Eukaryotic ribosomes 70s

*Prokaryotic ribosomes 80s

*Target for antibiotics

What are inclusions (storage granules)? Do all bacteria contain inclusions?

*Precipitated "chunk" of crystallized storage molecules

*Minimizes osmotic pressures thus minimizes h2o uptake

*All bacteria have them

What are chromosomes?

*Nucleoid

*Large double stranded loops of DNA

*Contains genetic information

*Bacteria typically have a single chromosome

*All bacteria have them

What are plasmids

*Small loop of DNA

*Contains accessory genes

*Can be exchanged with neighboring cells

*All bacteria have them

What are endospores? Which bacteria make them? How and when do they form? Why are they importantmedically?

*Cell with in a cell

*Highly resilient

*Produced by some bacteria in response to stressful environment conditions

*Bacillus and clostridium make them

*can remain dormant for long periods of time

What is C. diff? Why is it important medically?

*A lot of disinfectants won't get rid of its endospores

*Germinate and infect the intestines

*Problem in nursing homes and hospitals