Lecture 4: Domain Archaea and Domain Bacteria

bacteria and archaea are both

prokaryotes

smallest most abundant, most widespread, most ancient forms of life…

prokaryotes

cell structure of prokaryotes

unicellular, DNA is circular, no nucleus or membrane bound organelles, structurally simple

common shapes

cocci, bacilli, spirilla

spherical shaped prokaryote

cocci

rod shaped prokaryote

bacilli

spiral shaped prokaryote

spirilla and most dangerous

colonies

mass of individual bacteria cells which usually stick together, began with one cell, appearance can help identify

reproduction

reproduce through binary fission and quickly

binary fission

ring of DNA replicated and cell pinches in two making two identical cells, no mitosis or meiosis

capsule or slime layer

sticky layer of protein or polysaccharide that surrounds the cell wall so cells can adhere to one another or other substrate

polysaccharide

carbohydrate

fimbriae

hair-like appendages that allows cells to stick to one another or other things

endospore

a protected copy of chromosomes that is resistant to drying, heat, acids and some disinfectants and can survive for decades or centuries and are produced to exist until conditions are more favorable and are not reproduction but protection

nutritional and metabolic adaptations

oxygen metabolism and mode of nutrition

oxygen metabolism is

aerobic, anaerobic, facultative

aerobic

need oxygen to survive

anaerobic

poisoned by oxygen

falcultative

can tolerate any amount of oxygen

obligate

strict

mode of nutrition

organisms need nutrition in the form of energy or electrons and carbon these are found in light, organic compounds and inorganic compounds, but not all organisms need all 3

light

is the electron source for photoautotrophs and photoheterotrophs

organic compounds

contain carbon and hydrogen, large molecules, associated with life, source of carbon for heterotrophs

inorganic compounds

Do not contain carbon or hydrogen, smaller molecules, associated with environment, source of carbon for autotrophs

example of bacteria cyanobacteria

photosynthetic, large, cell walls of peptidoglycan, old

example of domain bacteria eubacteria

true bacteria, gram negative of positive, genetically diverse, cell walls made of peptidoglycan

peptidoglycan

mesh layer made of mostly carbohydrates

gram negative

thin layer of peptidoglycan inside an outer membrane, stains pink, outer membrane is toxic

gram positive

thick layer of peptidoglycan, stains purple

example of domain archaea methanogens

most plentiful archaea, produce methane gas, obligate anaerobes, break down cellulose, decomposers at sewage plants

example of domain archaea extreme halophiles

salt loving, range from aerobic to anaerobic, able to live in high salt concentrations, have highly adapted cell walls

examples of domain archaea extreme thermophiles

heat loving, obligate anaerobes, also thermoacidophiles

major differences between domain bacteria and archaea

metabolism, structure, and habitat

domain bacteria are…

photoautotroph or chemoautotroph

domain bacteria photoautotrophs

either have the green photosynthetic pigment chlorophyll A and do produce oxygen as a byproduct or have the purple photosynthetic pigment bacteriochlorophyll and don’t produce oxygen as a byproduct

domain archaea are…

photoautotrophs, chemoautotrophs, or photoheterotrophs

domain archaea photoautotrophs…

simplest form of photosynthesis known, have yellow photosynthetic pigment bacterior Hopsin and don’t produce oxygen as a byproduct

domain bacteria cell wall material

peptidoglycan

domain archaea cell wall

ranges from pure carbohydrate to pure protein, don’t have peptidoglycan and have unique plasma membrane

domain bacteria habitat is

everywhere except the most extreme environments

domain archaea habitat is

everywhere including extreme places because they are extremophiles

bacteria saprobes

decompose organic molecules or dead organism

symbiosis

ecological relationship where 2 species live in close contact, mutualism, commensalism, parasitism

mutualism (+/+)

both species benefit from association

commensalism (+/0)

one species benefits the other is neither benefited nor harmed

parasitism (+/-)

one species benefit and the other is harmed

virus

an infectious particle consisting of little more than genes packaged in a protein coat, smaller and simpler than prokaryotic cells

phage

category of viruses that infect bacteria cells

prion

an infectious agent of a misfolded version of a normal cellular brain protein, slow acting, not killed by heat

a virus particle/virion is made up of

genetic material, capsid, plasma membrane and does not have cells or metabolic abilities

capsid

protien container

viruses survive by…

hijack material and organelles from host, bind their glycoprotein to the host receptor protein to get access to the cell, use the host cells protein making abilities to replicate viral DNA/RNA

glycoproteins

like the key and are unique to 1 type of cell but some can species jump

glycoprotein species jumping

some keys can match the receptor cell of more than one species

DNA viruses

do not change quickly because the process of creating DNA checks for errors so there is less mutations and vaccines can be developed to fight infections

RNA viruses

have no error checking mechanism so they mutate rapidly