Bacteria

How Discovered? Draw and label.

Describe cell structure and how moves.

How obtains food and energy?

Explain types of bacteria reproduction.

List and explain the roles of bacteria in nature.

Late 1600’s---Anton van Leeuwenhoek made a microscope---Technology Took scrapings from mouth---Bacteria/Bacterium (s)

Prokaryotes---no nucleus---few cell structures---have cell wall like plants---Cytoplasm contains genetic materials---primitive form of life

Movement: Most cannot move on their own—carried by air, water, objects

Some bacteria have one or more flagellum---whiplike structures that spin

Can be autotrophs (make own food) or heterotrophs (consume meat,Milk, decaying leaves

Energy come from breaking down foods---Respiration---most need oxygen for this process others die in oxygen

Binary Fission---one cell divides into two identical cells---one parent-- asexual reproduction---copies genetic materials then splitsConjugation---one bacterium transfers genetic material to another through thread like structure---after transfer cell separate---then cells divides by binary fission---new combinations of genetic materials---two parents---type of sexual reproductionEndospore Formation---thick-walled resting cell forms to protect genetic material

of bacterium in extreme environments---when conditions become favorable will

open up and begin to grow

Produce Oxygen---product of photosynthesis---made by autotrophs

Food Production---activities of bacteria produce cheeses, sauerkraut, pickles, vinegar, buttermilk, yogurt, sour cream---Some bacteria cause foods to spoilEnvironmental Recycling—break down chemicals in dead organisms---decomposers

Environmental Cleanup---convert poisonous chemicals in to harmless substancesHealth & Medicine---bacteria in your intestines help digest food and produce vitamins--- used in making medicines

Characteristics

• Bacteria are smallest living organisms

• Bacteria consist of a single cell

• Bacteria are nearly 3.5 billion years old. They are among the earliest forms of life that appeared on Earth.

Bacterial Cell

• Bacterial cells are prokaryotic – they have no nucleus or other membrane-bound organelles

• Bacterial cells have a single chromosome – a circular DNA molecule

• Bacterial cells have a cell wall• Most bacteria reproduce by binary fission

Classification

• Bacteria fall into a category of life called the Prokaryotes. Prokaryotes' genetic material, or DNA, is not enclosed in a cellular compartment called the nucleus.

• Bacteria and archaea are the only prokaryotes. All other life forms are Eukaryotes, creatures whose cells have nuclei.

What they look like?

• There are thousands of species of bacteria, but all of them are basically one of three different shapes.

1. Cocci are shaped like little balls

2. Bacilli are rod- or stick-shaped

3. Spirilla are helical or spiral in shape

What they eat?

• Autotrophs photosynthetic bacteria can make their own

food from carbon dioxide using sunlight, just like plants.

chemosynthetic bacteria produce their own organic compounds from inorganic substances such as iron or sulfur.

• Heterotrophs needs organic substances that have already

been assembled by autotrophs.

Where they live?

• Bacteria live just about everywhere: in the soil, water and air; in animals, plants, rocks and even in us!

Bacteria from boiling water of hot springs in Yellowstone

National Park

Bacteria on our teeth

Spores

• Spore (or endospore) is a dormant cell. It has a tough shell that insulates and protects the genes and basic cell parts.

• Spores are resistant to heat and cannot be readily destroyed, even by boiling.

• In 2000, scientists revived bacteria that had lain in suspended animation for 250 million years.

Role of bacteria

Negative:• Bacteria can cause illnesses:

DiarrheaLyme diseaseBotulism

Leprosy

• How can you protect yourself and others from contamination by pathogenic bacteria?

Wash up!

Role of bacteria, cont.

Positive:

There are many important jobs bacteria do.

• They are used to make medicine.

• They break down oil from oil spills.

• They make about half of the oxygen we breath.

• They are the foundation of the food chain that feeds all life on earth

Our Friends

Bacteria do many good thins for us:

Escherichia coli: one of many kinds of microbes that live in your gut. Wanted for helping you digest your food every

day.

Pseudomonas putida: one of many microbes wanted for cleaning wastes from sewage water at water treatment plants.

Streptomyces: soil bacteria wanted for making streptomycin, an antibiotic used to treat infections.

Lactobacillus acidophilus: one of the bacteria gang wanted for turning milk into yogurt.

Protists

What is a Protists?

Tell about animal-like Protists. List the 4 types, tell their characteristics and how they move.

Tell about plant-like Protists. List types and characteristics of each.

Fungus-like Protists: Characteristics and how they reproduce.

Eukaryotes (cells have nucleus) that cannot be classified as animal,Plant or fungi

Very diverse Kingdom

Animal like---heterotrophs---able to move to obtain food---unicellular

Amoeba—move and feed by pseudopods---bulges called false feet

Ciliates---have hair like structures called cilia (oars)Flagellates---move with long whip like structures that spin

Parasites (characterized by how live not move)—feed on cells and body fluids of host---causes malaria---Protists carried by mosquito

Plant like---autotrophs—impt food source/produce oxygen---commonly called algae

Vary in size---unicellular and multicellular---vary in color---live alone or colonies

Diatoms—unicellular—glass like—good polishing agentDin flagellates—unicellular—armor plates—two flagella held in grooves

—spin and twirlEuglenoids—green—unicellular---can be heterotrophs—single flagellum—eyespot

sensitive to lightRed Algae/Green Algae/Brown Algae

Heterotrophs, have a cell wall and use spores to reproduce, able to move

Slime molds—form jelly like massWater molds---live in moist places---attack food--fuzzDowny Mildew---live in moist places—attack food--fuzz

Protists

• Protists are single celled eukaryotes. A few forms are multi-cellular.

• Protists often have a very complicated internal structure: a single cell must do all the functions that we have many different cell types to do.

• Protists can be divided into plant-like, fungus-like, and animal-like forms. This division probably has little to do with their evolutionary history.

Fungus-like Protists

• Water molds and slime molds

• Like fungi, they are heterotrophs: they get food and energy from other organisms. Many are decomposers of dead organisms.

• Unlike fungi, the fungus-like protists produce motile (moving) cells during part of their like cycle. Also, these protists surround and engulf bacteria as food.

• Slime molds live as separate cells most of their lives, feeding on bacteria. When conditions get harsh, they aggregate into a multicellular slug, which migrates to a new location. The slug then forms a fruiting body that generates spores. The spores from the fruiting body are very hardy.

Slime Molds

• Slime molds can be rather large and colorful.

Animal-like Protists

• The animal-like protists are classified according to how they move: amoeba-like, ciliated, or flagellated.

• Amoeba-like protists move by extending pseudopods, part of their cytoplasm, then pulling the rest of the cell along behind. The can surround and engulf their food this way.

Amoebas in Action

Ciliated Protists

• Cilia are small hairs surrounding the protist’s body. The cilia beat in a synchronized pattern to cause movement.

• Paramecium is a typical ciliate. It has a gullet to swallow food, and a contractile vacuole to get rid of excess water.

• Genetics: the DNA used for sexual reproduction is stored in the small micronucleus. A copy of this information is used to run the cell: the copy is kept in the much larger macronucleus.

Flagellates

• Flagellates have a small number of long flagella, long whiplike hairs that beats to propel the cell.

• Some nasty parasites are flagellates, including those which causes diarrhea and which is found in most of the surface waters of the US. Another is causes sleeping sickness in Africa.

Sporozoans

• Sporozoans are animal-like protists that have part of their life cycle inside the cells of their hosts.

• The most important example is Plasmodium, the parasite that causes malaria. Malaria kills 1-2 million people each year.

• Mosquitoes are part of the life cycle. They suck blood from infected humans, ingesting the sporozoans. The sporozoans undergo sexual reproduction in the mosquito’s gut.

• When the mosquito bites another person, the sporozoans infect the blood and liver of the host. The parasites multiply asexually inside the red blood cells, destroying them as they leave.

Algae

• The plant-like protists are called algae. Most are single-celled, but a few form large multicellular seaweed.

• The plant-like protists have chloroplasts. Some, like the Euglena, also have flagella for movement.

• Some, such as the diatoms, have calcium carbonate (chalk) or silica shells.

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Test Wednesday 9/12