Prokaryotes

Lecture 3

What are the similarities between Bacteria and Archaea?

• Prokaryotes

• single cell organisms

• no nuclei

• very small

What do bacteria have that archaea does not?

• Cell wall have peptidoglycan which strengths them

What is a difference between bacteria and archaea?

• machinery to replicate DNA is different

What are flagella?

• have motor that are embedded into their cell wall that rotate the cell

• like a propellor and created forward motion

How do prokaryotes use different types of metabolism?

• Obligate anaerobes - don’t use oxygen

  • oxygen tends to stop their growth

  • tetanus

• Facultative anaerobes

  • can survive with oxygen and without oxygen

• Energy substrates

  • methane, benzene, sulfur, ammonia, petroleum

How do prokaryotes specifically bacteria survive extreme and diverse conditions?

• bacteria can sense the environment and form a endospore ( thick protective structure/coat)

• After an endospore forms, the bacterial cell that contains it breaks open, and the spore is released to the environment.

• Metabolic activity ceases until the spore encounters favorable conditions, at which time metabolism resumes and the spore develops into an active bacterium.

How do prokaryotes reproduce and share in information?

• Through binary fission

  • genetically identical copies of the original cell

  • essentially one cell splits into two

• Conjugation

  • sharing genetic information through direct contact

  • plasma membranes of two conjugating prokaryotes fuse temporarily to form a cytoplasmic bridge across which DNA travels.

  • using a sex pili

    • critical to bacteria resistance against medicine

    • can share info about to improve function and survival of the bacteria

How is DNA seen in a Eukaryotes?

Linear strand within membrane bound nucleus

How is DNA seen in Prokaryotes?

single circle un nucleoid region (typically in the middle)

What is the typical size for a Eukaryotes?

• 5-100um

What is the typical size for a prokaryotes?

• 0.2-10 um

How are Eukaryotes organized?

• multicellular

• some have cell walls (no peptidoglycan)

How are prokaryotes organized?

• usually single celled

• some have peptidoglycan in cell walls

Do eukaryotes need oxygen to exist?

Yes

Do prokaryotes need oxygen to exist?

usually no but sometimes

What type of organelles do Eukaryotes have?

membrane bound organelles

• example - mitochondria

Example of Eukaryotes

• plants

• animals

• protists

• fungi

What type of organelles do prokaryotes have?

• actually have no organelles

• different types of ribosomes

Examples of Prokaryotes

• bacteria

• archaea

What are four ways antibiotics stop/kill bacteria?

• 1. Inhibits bacterial cell wall synthesis

  • inhibiting protein production - causing death of bacteria

    • E.g. Penicillin, Amoxicillin, Ampicillin - mole derivatives that kill bacteria

• 2. Inhibits protein synthesis

  • E.g. Tetracycline, Clindamycin - inhibit all blanket proteins

• 3. Alters the cell membrane

  • E.g. Bacitracin

    • affects all cell membranes not only diseased

• 4. Inhibits nucleic acid synthesis

  • E.g. Cipro - not bacteria specific

How do bacteria resist antibiotics?

• Antibiotic can’t get past the cell membrane or the cell wall

• Antibiotic gets in but the bacteria pumps it right back out

• The bacteria produces an enzyme/ protein that interferes with the antibiotic interacting with the target

• Bacteria produce an enzyme that chews up the antibiotic

What is the bacteria doing to the antibiotic?

Bacteria pump is taking out the antibiotic out

What is the bacteria doing to the antibiotic?

• The bacteria produces an enzyme/ protein that interferes with the antibiotic interacting with the target

What is the bacteria doing to the antibiotic?

• Bacteria produce an enzyme that chews up the antibiotic

What is missing?

Pili

What is missing?

Plasmid

What is missing?

Capsule

What is missing?

Cell Wall

What is missing?

Plasma Membrane

What is missing?

Nucleoid (DNA)

What is missing?

Ribosomes

What is missing?

Flagellum

What is missing?

Cytoplasm

How do prokaryotes move?

• Flagella

  • hair-like extensions that can rotate rapidly to propel the organism through its liquid environment

  • allows prokaryotes to disperse into new habitats, migrate toward nutrients, and leave unfavorable environments.

How do prokaryotes survive?

• Biofilms

  • In a biofilm, one or more species of prokaryote aggregate to form a community that is typically surrounded by sticky protective slime

  • protects the prokaryote and helps them adhere to surfaces

What are some positive bacterial interactions?

• Probiotics

• Bacteria in our gut contributes to the production to vitamin K and B12

• Nitrogen fixing bacteria

  • capture nitrogen gas (N2) from air trapped in the soil and combine it with hydrogen to produce ammonium

    (NH4+), a nitrogen-containing nutrient that plants can use directly.

• Bioremediation

  • stimulate breakdown of pollutants by living organisms

  • Oil eating bacteria to help clean up oil spills but the question is what do we do with the bacteria in environment after the oil spill is cleaned up?

What are some negative bacterial interactrions?

• C. botulinum

• Plague

  • Bubonic

  • Pneumonic

  • Septicemic

• Tuberculosis

• STDs

• Cholera

• Flesh-eating bacteria

MRSA

• over colonization of staph bacteria that is antibiotic resistant

• Red or tender skin around wound

• swollen, painful, oozing boils

Necrotizing Fasciitis

• flesh eating bacteria

• very low chance in getting it

• starts with a cut or insect bite then large sequence of events

• chews up tissue and tissue dies