Exam 1 Chapter 3 (Prokaryotic Cell)

prokaryotic cell

• no nucleus or membrane bound organelles

• older

• small

• rigid cell wall

Prokaryotic cells

are in domains achaea and bacteria

Appendages (external structures) of prokaryotic cell

• flagella

• pili

• fimbraie

• periplasmic fluid

Flagella

• Motile

• Used for movement and attachment

Pilli

• Tube structure used in horizontal gene transfer

• used for attatchment

Cell envelope consists of

• glycocalyx

• Cell wall

• Cell membrane

Glycocalyx

• Mixture of proteins + sugars

• Coating in exterior of cell

types of glycocalyx

• slime layer

• capsule

Slime layer

Loose mesh network of proteins + sugars

Capsule

• Dense mesh network of proteins + sugars

• More protective

slippery

Harder to grab

Bigger

Harder to engulf

Cell wall

• protection of cytoplasmic membrane from environmental stress

• Determines shape of cell

• Forms a mesh like structure

Cell wall keeps prokaryotes from

lysing from osmotic pressure

Two types of cell wall

• Two types

  • Gram + (pink)

  • Gram - (purple)

Gram +

• teichoic acid and peptidoglycan

• thick

Gram -

• lipopolysaccharide (LPS)

• thin

Lipopolysaccharide (LPS)

• causes immune cells to freak out and release signals

• can cause fevers, hemorrhaging, and septic shock

Acid fast

• mycolic acid

• waxy coating

• stain gram +

• hydrophobic

Difference between gram + and acid fast

Acid fast has mycolic acid

Name of genus that has mycolic acid

Mycobacterium

Carbol fushin

Acid fast stains binds to colic acid

Antibiotics are

Hydrophilic

Cytoplasm consists of

• matrix

• ribosomes

• Inclusion bodies

• nucleoid region

• endospores

All cells have

Ribosomes

Nucleoid region

Contains DNA

Endospore

Only spore former

Why are endospores important?

• preserve genetic information for future generations

• allow cells to survive in harsh environmental conditions

Morphology

• Coccus

• Bacillus

• Vibrio

• Coccabacillus

• Spirllium

• Spirochete

Coccus

Round

Bacillus

Rod

Vibrio

Curved rod

Coccabacillus

Short rod

Sprillium

Spiral

Spirochete

Helical shape

Cell arrangements

• Coccus

• Diplococcus

• Tetrad

• Streptococcus

• Staphylococcus

• Bacillus

• Streptobacillus

coccus

single coccus

diplococcus

pair of two cocci

tetrad

four cells in a square

streptococcus (important)

chain of cocci

staphylococcus

cluster of cocci

bacillus

single rod

streptobaccillus

chain of rods

osmotic pressure

water moves across the cell membrane to areas of high solute concentration

hypotonic solution

• water moves into the cell

• cell can burst or die due to too much water

• cell wall attempts to stop cell membrane from expanding

hypertonic

• water moves out of cell

• cell membrane detach from cell wall leading to a shrunk cytoplasm

isotonic

cell stays the same

inclusion

help reduce osmotic pressure by storing excess nutrients or solutes in a condensed form, lowering concentration of free solutes in the cytoplasm

endospores

form because of loss of nutrients

sporolation

process of forming spores

sporolation process

1. DNA replicates

2. Membranes form around DNA

3. Forespore forms additional membranes

4. Protective cortex forms around spore

5. Protein coat forms around cortex

6. Spore is released

Example bacterias ( Endospores)

• Genera Bacillus and Colstridium

• B. anthracis - anthrax

• C. tetani - tetanus

• C. difficile - pseudomembranous colitis

• C. perfringens - gas gangrene

• C. botulinum - botulism

Temperatures (vegetative vs endospores)

• vegetative = sensitive to extreme temperatures and radiation

• endospores = resistant to extreme temperatures and radiation

Gram stain (vegetative vs endospores)

• vegetative = gram-positive

• endospores = do not absorb gram stain

Water (vegetative vs endospores)

• vegetative = normal water content and enzymatic activity

• endospores = dehydrated, no metabolic activity

Growth (vegetative vs endospores)

• vegetative = active growth and metabolism

• endospores = no growth or metabolic activity

macrophages

marines of the immune system

cytokines

massive release of cytokines over the body send patient into crisis = lower blood pressure

Water

• Always go to where there is more stuff (solute)

• Can cross plasma membrane slowly but consistently

All cells are in

a hyptonic solution

A hypertonic environment will cause prokaryotic cells to go through

Plasmolysis

Prokaryotic ribosome

70S

Antibiotics target

70S (prokaryotes)

Ribosomes

Perform translation

DNA →(transcription) mRNA →(translation) protein

Bacillus + clostridium

Can form endospores