7th Grade - Mrs. Boguslaw Microorganisms, Fungi, and Plants Chapter 2 Bacteria and Viruses 7th Grade - Mrs. Boguslaw Microorganisms, Fungi, and Plants Chapter 2

Bacterial Cell

Bacterial Cell Capsule: extra protection for the cell

Bacterial Cell Cell Wall: support and structure for the cell

Bacterial Cell Cell Membrane: controls nutrients and wastes entering and leaving the cell

Bacterial Cell Cytoplasm: fluid that fills the cell

Bacterial Cell Nucleoid: central region of DNA

Bacterial Cell Ribosomes: make proteins

Bacterial Cell Flagella: helps the cell move through the environment

Bacterial Cell Pili: allow bacteria to attach to surfaces, including other bacteria

Three Common Shapes Bacilli - rod shaped, large surface area Pro: helps take in nutrients Con: dries out easily

Three Common Shapes Cocci - spherical Don’t dry out as quickly as rod- shaped

Three Common Shapes Spirilla - long and spiral- shaped Use flagella at both ends to move like a corkscrew

Bacterial Reproduction Binary fission asexual single-celled organisms only one cell divides into two cells that are the same size

Endospores Most bacteria like warm, moist places If it’s dry or cold, some bacteria will die…others will become inactive and form endospores Endospore: thick protective spore that forms inside a bacterial cell and resists harsh conditions When conditions improve, endospore breaks open and bacteria becomes active again

How are bacteria classified? By how they get food Decomposers, Consumers, or Producers

Cyanobacteria Producers Usually live in water Can have different pigments to help in photosynthesis - green, blue, red Scientists theorize that plants may have come from cyanobacteria living inside larger cells - bacteria provided food, cells provided protection

Archaea Live in EXTREME environments, often where nothing else can live Different from bacteria - might not have a cell wall, and if they do, it is chemically different Three main types: heat lovers - ocean vents and hot springs salt lovers - Great Salt Lake, Dead Sea methane makers - swamps and animal intestines

Bacteria’s Role in the Environment Chapter 2, Section 2

Good for the Environment Nitrogen Fixation Nitrogen gas makes up 78% of the air, but most plants can’t use it directly Nitrogen-fixing bacteria take in air from the environment and change it to a form plants can use

Good for the Environment Recycling Decomposer bacteria break down dead plant and animal matter This makes nutrients available for other living things

Good for the Environment Cleaning up Bioremediation: the biological treatment of hazardous waste by living organisms Changes harmful chemicals into harmless ones Cleans up hazardous waste from industries, farms, and cities Can clean up oil spills

Good for People Bacteria in Food Lactic-acid producing bacteria break down the sugar in milk, which adds flavor and preserves the food Cheese, yogurt, buttermilk, sour cream Other non-dairy foods: sauerkraut, sourdough bread, olives, dill pickles, soy sauce, salami

Good for People Making medicines Antibiotics: medicine used to kill bacteria and microorganisms Many antibiotics are actually made by bacteria

Good for People Making medicines Insulin - used by the human body to break down and use sugar and carbohydrates People with diabetes do not make enough insulin Scientists put genes to make insulin into bacteria - they then separate the bacteria from the insulin and give the insulin to people who have diabetes

Good for People Genetic engineering Scientists can change the genes of bacteria by adding genes from other organisms We can engineer bacteria to make many products, including insecticides, cleansers, and adhesives

Harmful Bacteria Pathogenic bacteria: bacteria that cause disease Pathogenic bacteria get inside a host organism and take nutrients from the host’s cells Vaccines and antibiotics are ways humans fight

Harmful Bacteria Bacteria can attack plants, animals, protists, fungi, and even other bacteria Can damage crops Odd colored spots and soft rot in plants can be caused by bacteria

Viruses Chapter 2, Section 3

Virus a microscopic particle that gets inside a cell and often destroys the cell tiny, smaller than the smallest bacteria 5 billion virus particles could fit in a drop of blood Change VERY rapidly Hard to fight

Are viruses alive? If something is alive, what can it do?

Are viruses alive? Viruses contain protein and genetic material, but can’t… eat grow break down food use oxygen Reproduce on their own

Are viruses alive? …no.

Are viruses alive? A virus cannot function on its own needs a host to survive and reproduce host: an organism from which a parasite takes food or shelter Viruses use a host’s cell as a tiny factory - forces cell to make viruses instead of healthy new cells

Classifying Viruses Viruses can be grouped by their shape, the type of disease they cause, their life cycle, or the kind of genetic material they contain (DNA or RNA). Every virus is made of genetic material inside a protein coat Protein coat protects the genetic material and helps a virus enter a host cell Many viruses have a protein coat that matches the characteristics of their particular host

Virus shapes Four main types: Spacecraft (Bacteriophage) Cylinder Crystal Spheres

Lytic Cycle A virus attacks living cells and turns it into a virus factory

Lysogenic Cycle Virus acts as a “time bomb” - puts in its genetic material but doesn’t build virus parts; each time the cell divides it passes down the virus’ instructions. May enter the lytic cycle at any time

Lysogenic Cycle

Treating a Virus Antibiotics DO NOT work! Antiviral medications can stop viruses from reproducing Because many viral diseases do not have cures, prevention is key - vaccines, good hygiene, staying away from wild animals If you’re sick, rest and get plenty of fluids