Bacteria and Viruses Chapter 10 Life Science

Bacteria More types of bacteria on earth than all other living things combined

Too small to be seen with the naked eye

All bacteria are single cell

Make up two of the 6 kingdoms (eubacteria and archaebacteria)

Archaebacteria and eubacteria are the oldest forms of life on earth

Rigid cell wall allows bacteria to retain their shape

Some bacteria have flagella to help them move around Flagella spin to push a bacterium through the water or liquid

3 shapes of bacteria 1.Bacilli 2.Cocci 3.Spirilla

Bacilli Rod shaped Large surface area which helps take in nutrients Large surface area also lets them dry out easily

Cocci Spherical Do not dry out as quickly as bacilli

Spirilla Long and spiral Use flagella at both ends to move like a corkscrew

Prokaryotes All bacteria are single cell organisms that do not have a nucleus Prokaryotes do not have a nucleus or membrane bound organelles Able to move, get energy and reproduce Function as independent organisms Some may stick together but is still a single organism

Bacterial reproduction Binary fission-reproduction in which one single-cell organism splits into two single cell organisms

Prokaryotes have no nucleus so their DNA is not surrounded by a membrane DNA is in circular loops

Steps of binary fission 1.Cell grows 2.DNA is copied and attached to the cell membrane (both DNA and DNA copy) but in separate spots 3.DNA and its copy separate as the cell grows larger 4.When cell is double its original size it pinches into and a new cell wall forms separating into two new cells each with an exact copy of the parent cell DNA

Endospores Contains genetic material and proteins and is covered by a thick, protective coat Bacteria become inactive and dormant when they become an endospore Happens in dry or cold surroundings which would kill the bacteria since they like warm, moist places

Many endospores can survive hot, cold, and very dry places When conditions improve the endospores break open and the bacteria becomes active again

Eubacteria Most bacteria Classified by the way they get food

Eubacteria classification 1.Consumer- get food from eating other organisms 2.Decomposers- feed on dead organisms 3.Parasite- live in or on the body of another organism 4.Producers- make their own food by using sunlight’s energy- often green

Cyanobacteria May have given rise to the first plants on earth Producers Live in water usually Contain chlorophyll and other pigments

Archaebacteria 3 main types 1. Heat lovers 2. Salt lovers 3. Methane makers

Heat loving bacteria Archaebacteria Live in hot springs Live in ocean vents (thermal vents from volcano) Survive temps of more than C

Salt loving archaebacteria Live in places that are extremely salty and nothing else can live there Dead sea Great salt lake in Utah

Methane making archaebacteria Give off methane gas Live in swamps Live in animal intestines Causes gas buildup in landfills

Archaebacteria usually live where nothing else can live Called extreme bacteria Cell walls are chemically different from eubacteria

Bacteria- Good for the Environment Nitrogen fixation Recycling Cleaning up

Nitrogen Fixation Plants need nitrogen to grow but cannot use it straight from the air Nitrogen fixing bacteria take in nitrogen from the air and change it into a form that plants can use This is called nitrogen fixation (fixing atmospheric nitrogen into a usable form of nitrogen)

Recycling Decomposer bacteria break down dead plant and animal matter into usable nutrients

Cleaning up Bacteria can be used to fight pollution Bioremediation (using microorganisms to change harmful chemicals into harmless ones) Bioremediation used to clean up hazardous waste from industries, farms, cities, and oil spills

Benefits for humans 1.Food 2.Medicines 3.Insulin 4.Genetic engineering

Food Lactose – sugar in milk Lactic acid producing bacteria break down lactose changing it into lactic acid which preserves and adds flavor to food Cheese, yogurt, buttermilk, cottage cheese, and sour cream are produced by bacteria Breads, sausages, pickles etc.

Medicines Antibiotics- medicines used to kill bacteria and other microorganisms Many antibiotics are made from bacteria

Insulin Insulin is used by the body to break down and use sugar and carbohydrates Diabetics do not make enough insulin 1970’s scientists discovered how to put genes into bacteria so that the bacteria would make the insulin which then could be separated from the bacteria and given to diabetics

Genetic Engineering When scientists change the genes of bacteria or any other living things

We can not engineer products such as insecticides, cleansers, and adhesives Started in 1973

Harmful Bacteria Called pathogenic bacteria (bacteria that cause disease) Get inside a host and take nutrients from the host Harm the host and sometimes kill the host Many bacterial diseases can be treated with antibiotics Vaccinate against some bacteria

Pathogenic Bacteria affects plants, animals, protists, fungi, and other bacteria Plants can be treated with antibiotics also Have genetically engineered certain plants to be resistant to disease-causing bacteria

Viruses Microscopic particle that gets inside a cell and often destroys the cell

Common cold (rhinovirus) Flu AIDS

Very tiny Smaller than a bacteria Change rapidly Do not know how many types there are due to the rapid mutations

Contain protein and genetic material Can’t eat Can’t grow Can’t break down food Can’t use oxygen Can’t function on its own

Host Living things that a virus or parasite lives on or in

Using a host’s cell the virus forces the host to make more viruses rather than healthy cells the body needs

Virus can only reproduce only inside a living cell that serves as a host

Viral groupings 1.Shape 2.Type of disease they cause 3.Life cycle 4.Kind of genetic material they contain

4 viral shapes 1.Crystals 2.Cylinders 3.Spheres 4.Spacecrafts

Crystals Shaped like a crystal

Cylinders Looks like a corn cob without the corn

Sphere Looks like a sphere

Spacecraft Attacks only bacteria

Every virus is made of genetic material in a shell The shell is a protein coat that protects the genetic material as the virus enters the host cell

Genetic material Either DNA or RNA RNA is made of one strand of nucleotides DNA is made of two strands of nucleotides

2 types of ways of making more viruses 1. Lytic 2. Lysogenic

Lytic Cycle 1.The virus finds and joins itself to a host cell 2.The virus enters the cell or injects the genetic material into the cell 3.Once the viruses genes are inside they take over the direction of the host cell and start making new viruses 4.The new viruses break out of the host cell (killing the host cell) and each new viruses finds another cell to infect and the cycle starts over

Lysogenic cycle The virus does not go directly into the lytic cycle The genetic material stays in the host cell Each new cell gets a copy of the virus genetic material as the original cell divides Genes stay inactive for long periods of time until something triggers them to become active

Treating a virus Most viruses do not have a cure Need to prevent from happening

Childhood vaccinations Antiviral medications Wash hands often Do not touch wild animals

Antiviral medicines Stop viruses from reproducing

Childhood vaccinations Gives the immune system a head start in fighting off viruses Helps prevent getting a viral infection

What to do when sick Drink lots of fluids Plenty of rest Checkup with doctor