Biology Prokaryotes, Viruses, Protists, Fungi, Plants

life is estimated to have begun when

over 3.5 billion years ago based on evidence from microfossils

microfossils

fossilized forms of microscopic life

prokaryotes

the most abundant forms of organisms, estimated only 1-10% species are known, found in every environment

archaea

one of two prokaryotic domains, the other being bacteria

all bacteria consumes what

ATP from the environment

aerobic bacteria uses

oxygen

characteristics of prokaryotes

• unicellular

• small cell size compared to euk

• no membrane bound organelles

• internal compartmentalization

• flagella

• circular chromosome of DNA, many also have plasmids

how do prokaryotes reproduce

asexually through binary fission

metabolic diversity

photosynthetic can be oxygenic or anoxygenic

anoxygenic

producing sulfur and sulfate

chemolithotrophic

produce carbohydrates using energy stored in chemical bonds

archea's differences from bacteria

• no peptidoglycan

• different lipid structure in membrane

• different structure of flagella

peptidoglycan

protein-carb found in bacterial cell walls that make their cell's walls rigid

archaeal groups

include methogens, halophiles, acidophiles, and thermophiles

methanogens

anaerobes that produce methane

halophiles

live in high salt levels

acidophiles

live in high acid environments

thermophiles

live and grow in higher temp environments

replication in archaea

single origin like bacteria but initiation and expression are more like eukaryotes

shapes of domain bacteria

rod-shaped, spiral-shaped, sphere-shaped

strepto

chains

staphylo

clusters

three bacterial cell shapes

bacillus, coccus, spirillum

gram stain

classifies bacteria into gram-positive or gram-negative

gram positive

thick layer of peptidoglycan in cell wall, appears purple under microscope after gram-staining

gram negative

thin layer of peptidoglycan in cell wall; appears reddish-pink under microscope after gram staining

early methods of characterizing bacteria

• mobility

• if it's photosynthetic

• unicellular or colonies

• spore formation

• pathogenic

molecular approaches to classification

• base sequences in DNA and RNA

• amino acid sequencing

• whole-genome sequencing

characterizing domain bacteria

relies on molecular approaches and rRNA sequences

Bergey's Manual of Systematic Bacteriology

a widely accepted method of classifying prokaryotes

most recent system of bacteria classification

thermophiles, gram-positive, photosynthetic, proteobacteria

gram-positive (characterizing bacteria)

bacilli and cocci species, actinobacteria

bacilli and cocci species

cause many diseases/infections in humans (anthrax, pneumonia, food poisoning)

actinobacteria

aerobic, decomposers, release antimicrobials

photosynthetic (characterizing bacteria)

cyanobacteria

cyanobacteria

base of many aquatic food chains, produce oxygen as a byproduct

proteobacteria

largest and most diverse group

what does proteobacteria include

beta, delta, and gamma (many are pathogenic)

major structures of prokaryotes

cell wall, cell membrane, cytoplasm, ribosomes, DNA; sometimes ribosomes, pili, endospores, flagella

bacterial cell walls contain

peptidoglycan

archaeal cell walls lack

peptidoglycan

cytoplasm

a semifluid solution w/ ribosomes, DNA, small organic and inorganic molecules

prokaryotic dna is

single closed loop, of double stranded DNA with some having plasmids

plasmids

small, circular, self-replicating loops of double stranded DNA

capsule

an outer covering of the prokaryote, made out of polysaccharides

what do capsules do

protects the cell against drying, pathogens, or harsh chemicals

pili

short, hairlike structures on the surface of some bacteria

what do pili do

they help bacteria connect to each other and to surfaces, such as those of a host cell

endospore

a thick-coated resistant structure formed by gram positive bacteria

when do endospores form

when environmental conditions become harsh

how prokaryotes move

• many prokaryotes have flagella

• taxis

• other modes (slime, twisting)

taxis

movement towards or away from stimuli

capsule (structure func.)

protects cells and aids in attachment

cell wall

protects cell and gives it shape

cell membrane

regulates movement of substances in/out

nucleoid region

contains genetic info

flagellum

used for motility

prokaryotes obtain nutrients from

either the nonliving environment or by utilizing the products or bodies of living organisms

heterotrophs contain

carbon from other organisms

autotrops contain

carbon from CO2

phototrops get energy from

light

chemotrops get energy from

chemicals in the environment

prokaryotes usually reproduce by

binary fission

genetic recombination in prokaryotes

transformation, conjugation, transduction

transformation

taking in DNA from the outside environment

conjugation

exchanging DNA with other bacteria via pili

transduction

transmission of bacterial DNA via viruses

decomposers

break down dead organisms and wastes

producers

photosynthetic varieties help form the base of many food chains

nitrogen fixers

bacteria that coverts nitrogen in the air into a usable form

how much nitrogen in the air is converted to usable nitrogen

90%

pathology

study of disease

pathogen

an organism that causes disease (bacteria)

vector

an intermediate host that transfers a pathogen or parasite

diseases include what species

humans, mosquitoes and other animals

antibiotics

• keep bacteria from growing and reproducing

• interfere with bacteria's cell functions

• do not harm host cell

antibiotic resistance

bacteria that antibiotics can't kill, caused by mutations of their DNA

overuse of antibiotics has created

R-plasmids that carry resistance genes (they have multiple resistances)

vaccine

weakened or killed pathogen, inactivated toxins

what do vaccines provide

active immunity

how do vaccines provide immunity

by stimulating the bodies immune system to recognize and destroy it

what do viruses not do

grow, show homeostasis, metabolize

what do viruses do

infect cells, use cell to make more viruses, causes diseases in many organisms