Classification and Viruses

Taxonomy

Taxonomy

Discipline of classifying organisms and assigning each organism a universally accepted name

Binomial Nomenclature

2-part naming system

Carolus Linnaeus

who classified organisms based on structure

Genus

A group of closely related species

Species

Group of similar organisms that can breed and produce fertile offspring

Kingdom

Largest taxonomic group consisting of closely related phyla

Virus

Strands of nucleic acid encase within a protein coat

How can a Virus reproduce

Can only reproduce within a host cell

Virus Vs Living cell

No metabolic apparatus Do not digest or respire Not made of cells They are crystalline Contain genes made of either DNA or RNA They can take over the cell activity They can cause contagious diseases

Classification system for Viruses

Baltimore Classification System

Baltimore Classification System

Type of Nucleic acid Single stranded or double stranded Whether or not they use reverse transcriptase

Virus Lytic Cycle

How a Virus produces

Attachment

The virus must attach to the cell wall or cell membrane of the host

Penetration

The virus must enter the cell through cell membrane fusion or endocytosis

Uncoating

The protein coat is worn away exposing the viral genome

Replication and Assembly

The viral genome takes over the host cell's machinery and creates more viruses

Lysis

The new virus particles rupture forth from the host cell

Lysogenic Cycle

Enters the host cell and its viral DNA becomes part of the host cells chromosomes. The host cell then has viral DNA. This is now called a Provirus. It can invade a cell but not kill it.

DNA viruses

Infect a host cell through a chance encounter and can cause some well known viruses. Since they have the same genetic material as humans, it doesn't have more steps for incorporation in the human nucleus.

RNA Viruses

Use RNA as their genetic material or use RNA intermediate to replicate

reverse transcription viruses

Convert RNA into DNA and incorporate it into host cell viruses that have genetic material in Nuclei

Bacteriophage

A virus that infects bacteria

Viruses and disease

Viruses cause common illnesses and deadly diseases

Virulence

The ability to cause disease and how deadly of a disease

Vectors

Carried by an animal

Airborne

spread through the air by people

Direct contact

an infected person touches a surface and is touched again

Fecal-Oral

Contaminated hands, food and water

Sexually transmitted

Direct transfer of bodily fluids

bacteria

uni-cellular and could be pathogenic

Uses of bacteria

nutrient cycles and are decomposers of organic material

Morphology

the study of the forms of things

Gram positive

Thick cell wall made of peptidoglycan

Gram negative

Thin cell wall made of lipoproteins

Use of Flagella and Cilia

used for movement

Bacillus

Rod

Coccus

sphere

Spirillus

spiral

Vibrio

boomerang

Spirochaetes

tight coils

Strepto

chain of bacteria

Staphylo

grape like cluster

Bacteria reproduction

asexually using binary fission

Plasmid

circular DNA. A small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.

Lag Phase

Bacteria adjusting to new environment and growing slowly

Log Phase

Exponential growth

Stationary Phase

Bacteria have reached the carrying capacity of the environment

Death Phase

Logarithmic death of bacteria as nutrients get used up

How do bacteria obtain energy?

photosynthesizers, chemoautotrophs, and heterotrophs

Photosynthesizers

large fraction of the world's ___ are carried by bacteria. Includes Cyanobacteria which have chlorophyll.

Chemoautotrophs

Breakdown chemicals in soil. Uses chemicals for nutrition. Their waste products act as fertilizer.

Heterotrophs

Most bacteria are ___. Serve as primary decomposers for the environment by releasing nutrients back to the soil after living things have died.

Mutualism

An interaction where all parties benefit

Parasitism

An interaction where one part benefits and the other is negatively affected

Pathogenic bacteria

Bacteria that can cause disease in organisms

How are bacteria harmful

Metabolize their host by using parts of the body as a food source. Bacteria cause disease by secreting chemical compounds called toxins into their environment.

Antibiotics

Used to treat bacterial diseases. They make a hole in the cell wall to allow natural defenses to be stronger or they stop the bacteria from reproducing.

Antibiotic-resistant bacteria

when bacteria multiply quicker than the antibiotics can kill and the surviving bacteria become resistant to the antibiotic and keep reproducing.

Superbug

A bacteria that is resistant to antibiotics due to overuse and cannot be destroyed.

Good bacteria uses

Act as decomposers Live in our digestive tract Foods are processed by bacteria

Aerobic

Grows with oxygen

Anaerobic

Grows without oxygen

Obligate aerobes

Must have oxygen

Obligate anaerobes

Must have no oxygen

Facultative anaerobes

grow with or without oxygen

Archaea

Prokaryote Oldest living organism survives in extreme conditions

Archaea contain

a cell wall made of polysaccharides and glycoproteins/lipids

Methanogens

Uses CO2 and Hydrogen to make methane as a waste product. Lives in the bottom of lakes and swamps in mud.

Thermoacidophiles

Live in the dark, without oxygen at a temperature of 750F and pH of 1-3. Live in hydrogen sulfide and other dissolved minterals.

Halophiles

Live in salt water (<15%)