Bacteria’s Role Bacteria’s Role in Our Worldin Our World

Good For the Good For the EnvironmentEnvironment

Of the thousands of Of the thousands of bacteria that live on bacteria that live on Earth, only a few Earth, only a few hundred cause hundred cause disease, like strep disease, like strep throat or a throat or a cavitycavity in in your toothyour tooth

Many bacteria do Many bacteria do things that are things that are important and even important and even helpful to ushelpful to us

Nitrogen FixationNitrogen Fixation

Most living things depend on plantsMost living things depend on plants Plants need nitrogen to growPlants need nitrogen to grow Nitrogen gas makes up Nitrogen gas makes up 78%78% of the air, of the air,

but plants can’t take it directly from the but plants can’t take it directly from the airair

They need to take in a different form of They need to take in a different form of nitrogennitrogen

Nitrogen-fixing bacteria take in nitrogen Nitrogen-fixing bacteria take in nitrogen from from air air and change it into form that and change it into form that plants can useplants can use

RecyclingRecycling Decomposer Decomposer

bacteria break bacteria break down down deaddead plant plant and animal matter, and animal matter, like in a like in a gardener’s gardener’s compost pilecompost pile

This makes This makes nutrients available nutrients available to other living to other living thingsthings

Cleaning UpCleaning Up BioremediationBioremediation: using microorganisms : using microorganisms

to change harmful chemicals into to change harmful chemicals into harmlessharmless ones ones

Used to clean up hazardous waste from Used to clean up hazardous waste from industries, farms, cities, and industries, farms, cities, and oil spillsoil spills

Bacteria in Your FoodBacteria in Your Food People raise bacteria for People raise bacteria for

food!food! Every time you eat cheese, Every time you eat cheese,

yogurt, buttermilk, or sour yogurt, buttermilk, or sour cream, you are also eating cream, you are also eating bacteriabacteria

Lactic-acid producing Lactic-acid producing bacteria break down sugar bacteria break down sugar in milk (lactose)in milk (lactose) Bacteria change lactose Bacteria change lactose

into into lactic acidlactic acid This preserves and adds This preserves and adds

flavor to the foodflavor to the food

Making Making MedicinesMedicines

AntibioticsAntibiotics Used to kill bacteria and other Used to kill bacteria and other

microorganismsmicroorganisms Many antibiotics made by Many antibiotics made by bacteriabacteria

InsulinInsulin Insulin breaks down and uses sugar and Insulin breaks down and uses sugar and

carbohydratescarbohydrates People with People with diabetesdiabetes do not make enough do not make enough

insulininsulin In In 1970’s,1970’s, scientists discovered how to put scientists discovered how to put

genes into bacteria to produce human insulin genes into bacteria to produce human insulin (bacteria are separated from the insulin)(bacteria are separated from the insulin)

Harmful BacteriaHarmful Bacteria In 1800s, scientists In 1800s, scientists

learned that some learned that some bacteria are bacteria are pathogenicpathogenic, , which means “which means “cause cause diseasedisease””

Pathogenic bacteriaPathogenic bacteria get get inside a host and take inside a host and take nutrients from the host’s nutrients from the host’s cells, harming the host in cells, harming the host in the processthe process

We are protected from We are protected from many bacterial diseases many bacterial diseases by by vaccinesvaccines and treated and treated with antibioticswith antibiotics

Diseases in Other Diseases in Other OrganismsOrganisms Have you ever seen a plant with odd-colored Have you ever seen a plant with odd-colored

spots or soft rot? It was probably damaged spots or soft rot? It was probably damaged by bacteriaby bacteria

Pathogenic bacteria attackPathogenic bacteria attack plants plants, animals, , animals, protists, protists, fungifungi, and even other bacteria, and even other bacteria

They can cause damage to grain, fruit, and They can cause damage to grain, fruit, and vegetable cropsvegetable crops

Branch of tree with bacterial disease called “fire blight”