Ch.26 Flashcards
Define bacteria
Prokaryotes that lack a membrane bound nucleus one of the largest branches in the tree of life
Define archaea
Prokaryote that lacks membrane bound nucleus one of the largest branches in thee of life
Devin microbiome
Is the community of microbes that naturally inhabit the body or parts of the body
The average human body is estimated to contain roughly
100 trillion bacteria and archaea cells
Extremophiles
Live in extreme habitats
In what habitats do extremophiles live in?
At ph less than 1.0
Temptress of 0°c under Antarctic ice
Water 155-10 times saltier than sea water
Pathogenic bacteria tend to infect tissues of
Entry point
Koch’s postulates
Is the causative link between a specific disease and microbe
Germ theory of disease
The theory of infectious disease are caused by bacteria, viruses, and other microbes
What are the 3 main ways infectious diseases spread
- Passed from person to person
- Transmitted by bites fom insects or animals
- ingesting contaminated food or water or exposure to microbes and surrounding environment
Antibiotics
Any substance that can kill or inhibit the growth of bacteria
Define bioremediation
Is the use of bacteria and archaea to clean up sites polluted with organic solvents
Koch’s 4 criteria that had to be met under Koch’s postulates
- microbe must be present in individuals suffering from the disease and absent from healthy individuals
2.the organisms must be isolated And grown in a pure culture away from host organisms
- If organisms from pure culture are injected into a healthy experimental animal, disease symptoms appear
4.organism isolated the diseased experimental animal again grown in pure culture and demonstrated to be the same as the original organism
How do we use Koch’s postulates today?
Used in modified forms to confirma causative link between new diseases and a suspected infectious agent
Germ theory of disease
States that infectious disease are caused by specific microbes in the body such as bacteria, archaea, and viruses
Infections diseases are spread in what 3 ways?
1.some are passed form person to person
- Someone transmitted by bites from insects or animals
- Some are acquired by ingesting contaminated food or water, on being exposed to microbes by ingesting contaminated food or waters
What makes some bacterial cells pathogenic?
Depends on virulence
Virulence
Ability to cause disease, its a heritable trait that varies among individuals in a population
How do toxins work?what do the do?
The bind to ribosomes and inhibits protein synthesis killing the host cells
Some pathogenic bacteria produce resistant Endospores
Endospores
Are tough thick walled dormant structures formed during times of environmental stress that contain Copies of cells DNA RNA ribosomes and enzymes
They also usually have resistance to high temperatures UV radiation and antibiotics
What do Antibiotics do?
- They can stop bacteria from growing
- it is produced naturally bu some soil Bactria and fungi
- discovered in 1928 used often by 1940
- with extensive use leads to drug resistant pathogenic bacteria
Biofilms
Are bacterial colonies emmeshed in polysaccharide rich Manx that shield Bactria from antibiotics
Role in bioremediation
- Fertilize contaminated sites to encourage growth of existing bact and arch
- Seeding, or adding specific species of bacteria and arch. To contaminated sites
How do biologists study bacteria and archaea?
Using enrichment cultures
Using metagenomics
Investigating human microbiome
Evaluating molecular phylogenies
What do enrichment cultures do?
The isolate populations of cells that grow under specific conditions
Thermopiles
Heat loving bacteria and archaea
What do Metagenomics/environmental sequencing do?
Identify species and biochemical pathways by comparing DNA sequences
Steps preformed in a metagenomic’s study
1.collectsamples from an environment containing a dyed Community of unknown organisms and extract DNA
- generate small DNA fragments and sequence as many as possible
- Compare these sequences with Mose of known genes. This info can be used to identify species and investigate biological processes
Direct sequencing
Direct sequencing is the isolation and sequencing of a specific gene from organisms found in particular habitat
human gut biome alone is composed of
100 trillion bacteria and archaea that play a vole in human health
Bacteria and archaea are
Prokaryotes
What themes occur in the diversification of bactena and archaea?
1 genetic variation through gene transfer
- Morphology
- Metabolism
Gene transfer occurs in 3 ways:
1) transformations
2) transductions
3) conjugation
Transformation
Is bacteria or archaea naturally take up DNA from the environment that has been released by cell lysis or secreted
Transduction
- Viruses pickup DNA from one prokaryotic cell and transfer it to another cell
Conjugation
When genetic info is transferred by direct cell to cell
Bacterial size
Volume of bacterial species
(Morphological diversity)
Bacterial shape
Whether they are filaments, spheres, rods and chain to spiral
(Morphological diversity)
Bacterial motility
Gliding motion or swimming motion with a flagella for ex
(Morphological diversty)
Gram stain
Dying system to examine cell walls
Gram positive
Cells look purple under a microscope
Gram negative
Cells look pink The cell wall has a thin layer containing peptidoglycan and Outer Phospholipid bilayer
Bacteria and archaea acquire energy to produce ATP in what three ways
- Phototrophs
- Chemoorganotrophs
- Chemolithotrophs
It is known as “ light feeders” that use light energy to excite electrons ATP is produced
Phototropns
It is known as “chemical carbon feeders” that oxidize organic molecules with high potential energy such as sugars that make ATP by cellular respiration or fermentation pathways
Chemoorganotrophs
It is known as “chemical rock feeders” that oxidize inorganic molecules with high potential energy where ATP is made by cellular respiration
Chemlithotrophs
Produce ATP and obtain carbon
- Autotrophs
- Heterotrophs
Known as “self feeders” that synthesize their own compounds from simple starting materials
Autotrophs
Know as “other feeders” that absorb ready to use organic compounds called building block compounds produced by other organisms in their environment
Heterotrophs
Fermentation
Make ATP without using electron transport chain
