Internal Bacteria Structure

Describe the plasma membrane structure of bacteria

• composed of phospholipids, imbedded proteins for transport and signal transduction, and markers

• fluid/moving

• may have hopanoid to decrease membrane fluidity and permeability

What is hopanoid?

• similar to cholesterol in eukaryotes

• decreases membrane fluidity and permeability in bacteria

What macronutrients do bacteria require?

• CHNOPS

• carbon

• hydrogen

• nitrogen

• oxygen

• phosphorous

• sulfur

• PICK MI

• potassium

• calcium

• magnesium

• iron

Describe basic bacterial nutrient uptake

• only take in dissolved molecule

• uptake is specific and efficient

• most often move nutrients against concentration gradient to store (requires ATP)

What are the types of active transport that bacteria use?

primary, secondary, group translocation

Describe primary transport

• one substance transported through uniporter

• hydrolosis of ATP for energy

Describe secondary transport

• two substances transported through cotransporters

• use ion gradient of one of the substances to power

Describe ABC transporter (ATP Binding Cassette)

• primary active transport

• solute binds to solute binding protein on PM

• transporter undergoes conformation change that allows solute through

• requires ATP hydrolysis

Describe Group Translocation

• active transport

• molecule chemically modified as it enters

• ex. PTS System

Explain the PTS System (Phosphoenolpyruvate: Sugar Phosphotransferase System)

• example of group translocation (active transport)

• imports a variety of sugars

• phosphate donated from PEP to Enzymes, which passes it to a protein

• phosphate then transferred to different enzymes

• enzymes bring sugars into cell and phosphoralyte the sugars

What special requirement do bacteria have to intake iron?

• use siderophores to intake insoluble iron

Describe siderophores

• compound secreted by bacteria that grab iron and release it to the cell or ABC transporter

• can be a virulence factor by stealing iron from host (allows bacteria to grow better)

What are the key cytoskeleton proteins in eukaryotes?

• actin

• intermediate filaments

• tubulin

Describe MreB and what eukaryotic structure it’s homologous to

• bacterial cytoskeleton protein

• similar role to actin, homologous structure

• provides shape to cell

Describe Intracytoplasmic membranes

• internal membrane structures within cytoplasm of some bacteria

• may connect to plasma membrane and would have a higher concentration of electron transport proteins

• Often in bacteria that are photosynthetic or nitrifying

What are thylakoids?

cyanobacteria internal membranes containing photocenters; type of intracytoplasmic membrane

What are inclusions? Provide two examples

• aggregates of organic/inorganic substances

• stored/concentrated for later date, often because would be toxic otherwise

• ex. Sulfur globules stored in inclusions as byproduct of anaerobic respiration in photosynthetic bacteria

• ex. Gas vacuole protein bound structures store gas to allow bouyancy in aquatic bacteria

Describe Carboxysomes

• type of inclusion

• in CO2 fixing bacteria

• fix CA to CO2 then convert to sugar

• for efficiency; make all the sugar in one palce

Describe magnetosomes

• type of inclusion

• used by aquatic bacteria to orient to Earth’s magnetic filed

Briefly describe bacteria ribosomes, including subunit size

• 70s total (30s and 50s subunits)

• made of rRNA and proteins

Describe eukaryotic cytosol ribosomes size

• 80S total, 40s and 60s subunits

Describe eukaryotic mitochondria/chloroplast ribosomes size

70s

What are nucleoids?

• unique regions within bacteria with DNA that has no membrane

• usually circular chromosomal DNA

• bacteria usually monoploid, but be polyploid (multiple copies)

• 500-1000 genes, compacted into macrodomains for space

Describe Nucleoid associated proteins (NAPs)

• proteins that help bacterial chromosomes bend and fold, stiffen, or link

• important for packaging before replication

Describe plasmids

• extrachromosal DNA in bacteria

• <30 genes, don’t have essential genes for growth, replication, etc. just fun stuff like AR

• transfered between organisms

• usually replicate independtely

• called episomes when integrated into chromosome

Describe episomes

• type of plasmid that’s integrated into chromosomes and replicates with it

• <30 non-essential genes

• transferred between organisms