biology chapter 20

• a rod shape (bacillus)
• a sphere shape (coccus)
• a spiral shape (spirillum)

• archaea
• bacteria

a single chromosome clustered in a mass called a nucleotide

small extra loop of dna

a protein-carb compound that makes up the bacterial cell wall.

this wall allows for the use of the gram stain

have a thick layer of peptidoglycan and no outer membrane. its stain is violet/purple

have a thin layer of peptidoglycan & have an outer membrane its stain is pink

organisms that get their energy from sunlight through photosynthesis

the only organisms that can get their energy from inorganic sources.

use molecules that contain sulfur or nitrogen & simple organic molecules

in the presence of hydrogen rich chemicals, chemoautotrophic bacteria can form all of their own amino acids and proteins.

most prokaryotes are this

get both energy & nutrition form other organisms

the means in which prokaryotes reproduce

a sexual

conjugation~ when 2 bacteria exchange genetic material

transformation~ when bacteria take up dna fragments from their enviroment.

transduction~ when genetic material, such as a plasmid, is transferred by a virus. plasmids often convey antibiotic resistance

thick wall structures

help bacteria survive harsh conditions

they form inside the bacteria they surround the dna and a small bit of cytoplasm

show no signs of life & can be revived after hundreds of years.

pieces of nucleic acid contained in a protein coat

not considered to be living

nucleic acid & a capsid

the protein coat of a virus encloses its genetic material.

viruses recognize their hosts by specific proteins on a host cell's surface. the proteins on the host cell have to match proteins on the capsid of the virus.

a membrane surrounding the capsid.

gives the membrane an overall spherical shape even if capsid is not.

its studded w/ receptors that help the virus enter cells. its made up of proteins, lipids, & glycoproteins

viruses that infect bacteria

aka phages

have a complicated structure

lytic and lysogenic cycle.

lytic~ the cycle of viral infection, reproduction, & cell destruction

lysogenic~ host shares viral dna. host cell is not destroyed.

when viral dna becomes part of its host cell's dna

a virus whose reproduction includes the lysogenic cycle

viroids & prions

a single strand of rna that has no capsid.

rna of virus < rna o virus

disrupt host cell's regulation of growth

misshapen versions of proteins that are found in the brain.

vital role in all ecosystems

produce oxygen, makes nitrogen available, & helps decompose dead organisms. many form symbiotic relations

important in genetic reasearch

their genetic mataerial is easily studied

valuable info on dna replication, transcription, and translation

used in gene therapy

technique for diagnosing the cause of an infection

• 1) pathogen must be found in an animal w/ the disease & not in a healthy animal
• 2) pathogen must be isolated from the sick animal & grown in a laboratory culture
• 3) when injected into a healthy animal, the animal must contract the disease
• 4) pathogen from 2nd animal must be the same as the original pathogen

by producing toxins

destroying body tissues( by producing enzymes that break down the host's tissues into nutrients that the bacteria can use)

the most common way that bacteria cause disease is by producing poisonous chemicals

chemicals that inhibit the growth of or kill micro-organisms

spreads when sensitive populations of bacteria are killed by antibiotics. as a result resistant bacteria thrive