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Bacteria. All bacteria. All bacteria are unicellular and prokaryotic . What types of organelles do prokaryotes have? Cell Wall Cell Membrane Flagella Free floating DNA (no nucleus). How do Bacteria get their food?. Some are Autotrophs
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All bacteria • All bacteria are unicellular and prokaryotic. • What types of organelles do prokaryotes have? • Cell Wall • Cell Membrane • Flagella • Free floating DNA (no nucleus)
How do Bacteria get their food? • Some are Autotrophs • Photosynthetic: Make food using sunlight (photo-) • Chemosynthetic: Obtain energy by breaking down inorganic chemicals (chemo-) like sulfur and nitrogen.
Some bacteria are Heterotrophs • Found Everywhere • They need to consume organic molecules as an energy source
Classification Bacteria are classified into two very different kingdoms ArchaebacteriaEubacteria
Archaebacteria Live in very extreme environments like • Oxygen- free Habitats (anaerobic) • Concentrated SaltWater • Hot, acidic waters of sulfur springs Have cell walls with no peptidioglycan Come in all different shapes
Eubacteria • Can live in a lots of different habitats • Kitchen, bathroom, hospitals, skin, air • Have cell walls with peptidioglycan • Are normally found as very specific shapes
Eubacteria Spirillum – Spiral shaped Coccus – round Bacillus – rod-shaped
Asexual Reproduction – Binary Fission A copy of bacterial DNA is made The copy (plasmid) attaches itself to the cell membrane As the cell grows the two copies separate. The cell divides, with each cell receiving one copy of DNA.
The two daughter cells are genetically identical to each other and the parent.
Sexual Reproduction Bacteria can also reproduce sexually through a process called conjugation. One bacterium transfers all or part of its DNA to another cell through a bridge-like structure called a pilus that connects the two cells.
Helpful Bacteria Nitrogen Fixation – Converts N2 gas into ammonia (NH3); then converted to nitrites (NO2) necessary for plants Decomposers – break down organic matter of dead organisms Fermentation – vinegar, yogurt, butter, cheese, and pickles.
What is a virus? A virus is a particle made up of nucleic acids, proteins, and sometimes lipids. Most viruses are made of up of a core of genetic material surrounded by a protein coat. Viruses have very different sizes and structures. A virus’s protein coat is called a capsid.
Parts of the virus bind to the surface of a host cell and “trick” the cell into allowing it inside. • Once inside, the virus. uses the host cell to make new copies of itself. • This process can destroy the host cell.
DNA or RNA? • All viruses have genetic material. Some have DNA while others have just RNA. • Viruses that have only RNA are called retroviruses. • When retroviruses infect a host cell, they produce a DNA copy of their RNA. This is backwards as mRNA is usually formed from DNA – hence the name “retro.”
What are the characteristics of living things? • Living things: • Are made of cells. • Reproduce. • Are based on a universal genetic code. • Grow and develop. • Obtain and use materials and energy. • Respond to their environment. • Maintain a stable internal environment. • Taken as a group, living things change over time.
Are viruses living things? • Are viruses made of cells? • Do viruses reproduce? • Are virsues based on a universal genetic code? • Do viruses grow and develop? • Do viruses obtain and use materials and energy? • Do viruses respond to their environment? • Do viruses maintain a stable internal environment? • Taken as a group, do viruses change over time?
Diseases Caused by Bacteria and Viurses Pathogens – disease-causing agents. - Actually only a few bacteria and viruses cause disease, even though they are found everywhere in nature. Influenza virus
Harmful Bacteria Only a few kinds of bacteria actually cause disease, those that do have a great impact on our lives. It is estimated that about ½ of all human diseases are caused by bacteria. Examples: Tuberculosis, pneumonia, cholera, pertussis, anthrax, whooping cough
Bacterial Disease in Humans • The French chemist, Louis Pasteur, was the first person to show convincingly that bacteria cause disease. • Pasteur helped to establish what has become known as the germ theory of disease when he showed that bacteria were responsible for a number of human and animal diseases
Bacteria cause disease two ways: • Some damage the cells by breaking down the cells for food. • Others release toxins (poisons) that travel throughout the body interfering with the normal activities of the host. (disrupting homeostasis)
Why do you get cavities in your teeth? • Tooth decay is caused by the Streptococcus mutans. • The bacteria destroys your teeth enamel.
Treatment for Bacterial Infections Antibiotics – compounds that block the growth and reproduction of bacteria. • Examples: Penicillin and tetracycline. • AntiBiotics TREAT Bacterial Infections
Penicillin • Discovered accidently in 1928 by Alexander Flemming • Left a plate of Staphylococcus bacteria open and noticed that a green mold called Penicilliumnotatumstarted to grow • No bacteria grew near the mold • Something produced by the mold inhibited the growth of the bacteria
Viruses are highly specific to the cells they infect. Plant viruses infect plant cells; most animal viruses infect only certain related species of animals. Viruses that infect bacteria are called bacteriophages.
Smallpox • Causes fever, fatigue, and the characteristic rash, spread through droplet inhalation. • 30% fatal • Eradicated in 1979
Herpes • Herpes Simplex 1 is typically the cause of oral herpes causing cold sores or fever blisters around the mouth. • Herpes Simplex 2 is typically the cause of genital herpes causing blisters in the genital area. • Both types of Herpes are spread by contact, and can spread even if there are no sores or blisters present. • The herpes virus can stay dormant in the body for years. • Outbreaks can occur in reaction to illness, fatigue, or stress.
Influenza – The Flu Virus • Attacks cells in the nasal passageways. • Transmitted by contact with contaminated objects or droplet inhalation.
Human Immunodeficiency Virus • The disease AIDS is caused by the HIV virus. • The HIV virus attacks Helper T cells, which are needed for normal immune system function, and destroys them. • People with HIV can develop AIDS, which means their immune system has been so destroyed that they get very sick from other infections. • Transmitted through bodily fluids.
Antibiotics do not treat viruses!! Vaccines – a preparation of weakened or killed pathogens that will “trick” the body into making antibodies. - Most vaccines will provide protection if they are used before an infection begins.
Anti-virals • Antibiotics have no effect on viruses • Anti-viral drugs like Tamiflu have been developed to fight certain viral diseases • These drugs inhibit the ability of viruses to invade cells and multiply once inside of cells
Did you know? • Over-the-counter drugs (non-prescription) only treat your symptoms of the disease • Cough • congestion, • Fever • These medicines may make you feel better but they do not treat the cause of the infection
What is the most important step in preventing disease transmission?