Bacteria

PA Standards

• 3.3.7 A Structural and Functional similarities and differneces among living things• Adapations among organisms that

live in a particulat enviroment• How to use a dichotomous key• Relationship between strucute and

function

PA Standards

• 3.3.7 D Explain the basic concepts of natural selection. Explain the mechanisms of evolutionary theory• Identify adaptations that allow

organisms to survive in their environment

PA Standards• 3.3.7 A Structural and functional differences

among living things• Explain significant biological diversity found in

each of the biomes• Identify and characterize major life forms by

Kingdom, phyla, class, order, genus and species• Describe how the structures of living things help

them function in unique ways• Identify and characterize major life forms

according to their placement in existing classification groups

• Explain interactions among organisms realtionships

PA Standards

• Know that every organism had a set of genetic instructions that determines its inherited traits

Distinguish how living thinfs reproduce

distinguish reproductive patterns of living things

Compare random and selective breeding practices

Prokaryotes

• The Kingdom Monera consists entirely of bacteria - very small one-celled organisms. To get an idea of just how small bacteria are, take a look at the width of a millimeter - the smallest units on the metric side of a ruler. A thousand bacteria can sit side by side in just 1 tiny millimeter!

Recall that prokaryotic cells are different from Eukaryotic

Cells

Eukaryotic Prokaryotic

Has a Nucleus

Has membrane bound organelles

Larger

More complex

Kingdom: Protista, Fungi, Plants, Animals

No Nucleus

No Organelles

Small

Simple

Kingdom: Monera (ALL BACTERIA

Cell Membranes

Cytoplasm

Genetic material

They are Everywhere !• Despite their small size, bacteria are

the most abundant of any organism on Earth. And they're everywhere! Bacteria can be found in the air, soil, water, on you, and inside you. In fact, there are more bacterial cells inside your gut and on your skin than there are cells in your entire body - no matter how many times you try to wash them off!

• Bacteria were among the first life forms on Earth. As a group, these bacteria are called heterotrophic anaerobes (ann-air-robes). Because there was virtually no oxygen in the atmosphere at this time, these bacteria were necessarily anaerobic, meaning they did not breathe oxygen.

Heterotrophs, meaning "other feeders", are simply organisms that cannot make their own food. So "heterotrophic anaerobes" means they were creatures which ate some naturally occurring food and did not breathe oxygen. The fossils of some these oldest known forms of life have been found in Australian rocks dating back 3.5 billion years.

Classifying Prokaryotes

• For many years, most prokaryotes were simply called “bacteria” and placed in a single Kingdom “Monera” More recently biologists have begun to divide them into two groups

• Eubacteria & Archaebacteria

Eubacteria

• The larger of the two groups of Prokaryotes.

• Scientists are still trying to decide how to classify these organisms

• The cell walls of Eubacteria contain Peptidoglycan, a type of carbohydrate NOT found in Archaebacteria

E- coli

Archaebacteria

• MOST X-TREME!!!!• Methanogens live in thick mud, digestive tracts, and other oxygen

free environments• Others live in Volcanoes, Hot

springs, Salt Lakes

Methanogens

• They are common in wetlands, where they are responsible for marsh gas, and in the guts of animals such as cows and humans, where they are responsible for the methane content of flatulence.

Identifying Prokaryotes

• Prokaryotes are identified by their:

• Shapes• Chemical Nature of their cell walls

• Movement

Shapes

• Bacilli- rods

• Cocci- Spheres

• Spirilla- spirals

Cell Walls

• Two types of cell walls exist in Eubacteria• Gram positive-

have a single cell wall

• Gram negative- have a second outer layer of lipids and carbohydrates surrounding the internal cell wall

Movement

• Flagella- whip-like tails used for movement

• Lash/snake/spiral

• Glide on slime

Obtaining Energy

• Prokaryotes have diverse adaptations that allow them to live in every environment imaginable

Obtaining Energy

• Autotrophs- “troph” ADJECTIVE:

1. Of or relating to nutrition. 2. Ecology Of or involving the feeding habits or food relationship of different organisms in a food chain.

Autotroph

• Autotroph• Auto “Self”• Autotroph- “an organism that gets

nourishment from itself

Photoautotroph

• Photo- Light

• Photoautotroph- organism that nourishes itself using light energy from the sun

Chemoautotroph

• Chemo- • Chemicals

• Chemoautotroph- organism that nourishes itself using chemicals

Heterotroph

• Hetero• Other

• Heterotroph- gets nourishment from outside sources (like us)

Respiration

• Obligate Aerobes- need a constant supply of oxygen in order to survive

• Obligate Anaerobes- MUST have NO oxygen (botulism)

• Facultative Anaerobes- OK with or without Oxygen- able to grow just about anywhere

Botulism• Botulism is a rare, but serious paralytic illness

caused by a nerve toxin, botulin, that is produced by the bacterium Clostridium botulinum. Botulinic toxin is one of the most powerful known toxins: about one microgram is lethal to humans. It acts by blocking nerve function and leads to respiratory and musculoskeletal paralysis.

• Outbreaks of foodborne botulism involving two or more persons occur during most years and usually are caused by eating contaminated home-canned foods.

Growth & Reproduction

• When conditions are favorable, prokaryotes can grow and divide at astonishing rates.

• In nature bacterial reproduction is held in check by the availability of food and resources

Reproduction

• Asexual- Binary Fission. Binary fission involves one parent and no exchange or recombination of genetic information

Reproduction- sexual reproduction in bacteria is

called conjugation

Conjugation

• During conjugation a bridge forms between two cells, and genes move from one cell to the other. This transfer of genetic information increases the genetic diversity in populations of bacteria.

Spores

• When growth conditions become unfavorable, many bacteria form structures called spores.

• One type of spore, an endospore can encapsulate the bacteria allowing it to remain dormant for months- centuries until more favorable growth conditions arise.

• Endospores of the bacterium Bacillus anthracis were used in the 2001 anthrax attacks. The powder found in contaminated postal letters was composed of extracellular anthrax endospores. Inhalation, ingestion or skin contamination of these endospores, which were technically incorrectly labelled as "spores", led to a number of deaths.

Bacteria in Nature

Bacteria act as Decomposers in nature. They take dead and decaying organisms and recycle them back into a form that can be used by other organisms.

Do you ever see piles and piles of dead organisms lying in the park?

No- Bacteria aids in breaking down their organic materials and recycling it back into the environment.

Nitrogen Fixers

• Plants need nitrogen to make amino acids

• (recall that proteins are made of amino acids)

• The process of converting nitrogen into a form plants can use is called Nitrogen Fixation

Pathogens

• Pathogens are disease causing agents

• Only a small percentage of all the bacteria in the world are pathogens.

Pathogens

• Bacteria cause disease in two ways:• 1. Break down tissues of infected organisms.

• 2. Release toxins into infected organisms

Antibiotics

• Antibiotics are compounds that block the growth and reproduction of bacteria

Antibiotic resistance is a consequence of evolution via natural selection. Those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring, which will be a fully resistant generation. Several studies have demonstrated that patterns of antibiotic usage greatly affect the number of resistant organisms which develop. Overuse of broad-spectrum antibiotics, greatly hastens the development of methicillin resistance. Other factors contributing towards resistance include incorrect diagnosis, unnecessary prescriptions, improper use of antibiotics by patients, and the use of antibiotics as livestock food additives for growth promotion.

Human Uses of Bacteria

• Food production: cheese, yogurt, sour cream, pickles, sauerkraut.

• Industry: some bacteria can digest petroleum making it useful in cleaning up oil spills.

• Pharmacy: Used to synthesize drugs and chemicals

Ways to control Bacteria

• Sterilization destroys bacteria by subjecting it to heat or chemical action

• Refrigeration- most bacteria grow much slower at low temperatures

Viruses

• Viruses have only some of the properties that characterize life

• Like living cells, viruses have genes and can reproduce.

• However, they can NOT reproduce on their own.

• Viruses rely on living organisms to help them reproduce and make proteins

Viral Infections

• Two ways that viruses infect host cells are;

• Lytic or,• Lysogenic Infections

Lytic Infections

• Lytic Infections occur when a virus enters a host cell, replicated within the host cell, then causes the host cell to burst thus releasing many more viruses into the blood stream

• This type of infection destroys the cell

Lytic Infection

Lysogenic Infections

• Lysogenic Infections enter a host cell embed themselves in the host cell’s DNA and then manipulate the host cell for their own EVIL doing…..zombie cells.

• This type of infection does not destroy the cell

Common Viruses

• Cold• Flu• HIV

Treatment

• Viruses can NOT be treated with antibiotics

Non- Living Pathogens

• Two other non-living pathogens are viroids which infect plants, and prions which disable a proteins ability to fold correctly