Ch24 prokaryotes

prokaryotes domains include

bacteria and archea

plasmids

may have accessory rings of DNA

prokartotic cells

do not have a nucleus, lack membrane bound organelles, smaller, simple structure, divided by binary fission, include bacteria and archaea

Eukaryotic cells

have a defined nucleus enclosed by nucleus membrane, contain membrane bound nucleus, larger, have a complex structure, have linear DNA, divided by mitosis or meiosis, include pants/animals/fungi/protists

prokaryotic DNA is located in

nucleoid region instead of membrane bound nucleus

Prokaryotes cell shapes

sphered, rods, and spiral

prokaryotes are

Unicellular

Cell walls

protect and maintain cell shape, prevent bursting

peptidoglycan

a network of modified sugars and polypeptides (proteins) contained in bacterial cell walls

archaeal cell walls

contain polysaccharides and proteins but peptidoglycan

capsule

many prokaryotes also have a sticky protective outer layer that allows them to adhere to the substrate or each other

gram positive bacteria

have simpler cell walls composed of a thick layer of peptidoglycan

gram negative bacteria

have less peptidoglycan and an outer membrane with liposaccharides (can be toxic)

taxis

about half of all prokaryotes exhibit taxis, the ability to move toward or away from stimulus

fimbriae

prokaryotes stick to there substrate or each other using hairlike appendages

Pili (sex pill)

are loner, less numerous appendages that are used to pull prokaryotes together during DNA transfer between cells

endospores

are dormant cells that can remain viable, when water or nutrients are lacking, some bacteria develop these resistant cells

flagella

the most common motility structure in prokaryotes, likely evolved independently

bacteria flagella

composed of three main parts: motor, hook, filaments

Exaptation

when existing structures take a new functions though decent with modification Ex: bacterial flagella is an example of this

nucleoid region

where chromosomes are located and are not surrouned by the membran

plasmids

bacteria that also have smaller rings of DNA. typically only carry a few genes

what are oxygen requirements

-obligate aerobes are unable to grow in the absence of oxygen

-obligate anaerobes unable to grow in the presence of free oxygen

-facultative anaerobes unable to grow in either the presence or absence of free oxygen

anoxygenic

green sulfur and some purple bacteria living in oxygen poor conditions

cyanobacteria

believed to be responsible for introducing oxygen into primitive atmosphere

chemoautotrophs

Organisms that obtain energy by oxidizing inorganic substances, using this energy to convert carbon into organic compounds.

chemosynthetic

make there own organic compounds

most prokaryotes are..

chemohetertrpohs

saprotrophs

Organisms that decompose organic matter.

biofilms

are structured communities of microorganisms adhered to surfaces, can cause wide range of problems

antibiotics

are substances that kill or inhibit the growth of bacteria (only bacteria). Targets cell walls and metabolism (DNA)

prokaryotes produce……………..by means of

asexually, binary fission

some bacteria form….

resistant endospores

genetic recombination

the combining of DNA from two sources, contributes to diversity

Horizontal gene transfer

Transfer of genetic material between organisms, bypassing traditional reproduction. Genes among individual from different species

3 bacteria deisaes in humans

Chlamydia, strep throat, and lyme disease

spirochetes

helical gram negative heterotroph, need a host

archaea was formally known as

bacteria

Halophiles (salt)

require high salt concentration for growth

thermoacidophiles

Microorganisms that thrive in hot (80), acidic environments.

Methanogens

produce methane from hydrogen gas and carbon dioxide

mutualism

when both ends benefit

parasitism

A relationship where one organism benefits at the expense of another.

Commensalism

A relationship where one organism benefits and the other is neither helped nor harmed.

endotoxins

are released when bacteria die and the cell wall breaks down

exotoxins

are proteins that are secreted and can cause disease even if the bacteria are no longer present

photoautotroph

Organism that converts light energy into chemical energy through photosynthesis

chemoautotroph

Organism that derives energy from inorganic compounds

photoheterotroph

Organism that uses light for energy but requires organic compounds for carbon.

chemoheterotroph

Organism that uses inorganic molecules for energy and organic compounds for carbon.