Bacteria

Chapter 7

Bacteria Sec 7-1H.W. pg 193 ques. 1-4

We can find bacteria everywhere. From your skin, right now, to hundreds of feet under the Earth.

Some can live in extremely hot temps: thermophiles.

Some live in high salt environments like oceans: halophiles.

Some live in areas of high pressure: barophiles.

Phile means to like. And Phobic means to hate.

Bacterial Structure

Bacteria come in three different shapes: 1) rods- bacillus

2) spheres- cocci

3) spirals- spirillium

Bacterial Structure

Bacteria are single celled organisms that are smaller than plant or animal cells.

These single cells can be found alone or in groups. Their cells contain cytoplasm that is surrounded by a

cell membrane and sometimes, also by cell wall. They are considered Prokaryotic, because they lack

membrane bound organelles and they have no nucleus.

They contain one circular chromosome, which is located in the cytoplasm.

They do have all of the other organelles that an animal cell would have; such as ribosomes, mitochondria, etc…..

Special features

Some bacteria have a thick cell wall that allows them to be resistant to antibiotics, and immune cells.

Some have protein spikes on their surface called pili, that allow for them to attach to a cell it wants to infect.

Some have flagella to allow better movement.

Bacterial Structure

Bacterial reproduction & Energy

Bacteria reproduce by a process called Fission or splitting.. This is a form of asexual reproduction that produces to genetically exact copies from one parent cell.

Some bacteria are able to make their own food by using chlorophyll for photosynthesis.

Some are consumers and have to feed on other organisms for energy. Soe brae; down an feed on dead organism, decomposers.

Some absorb nutrients from a host that they are living in, parasite.

Bacterial reproduction & Energy

Some bacteria use Oxygen to break down their food through respiration. They are called aerobes.

Some bacteria don’t use oxygen for food breakdown, or other processes is called an anaerobe.

If you were to grow a aerobic bacteria in a test tube. I would grow near the top so it can get Oxygen.

Where would an anaerobe grow?

Eubacteria vs. Archaebacteria

Eubacteria is the larger of the 2 kingdoms, and means new bacteria.

They are classified by the way the get food, shape, type of food they eat, and the waste they produce.

One bacteria that produces is own food by photosynthesis is cyanobacteria. It is important because it releases Oxygen as a waste product.

Along with chlorophyll, it has a blue pigment also, so it is called the blue-green bacteria.

Eubacteria vs. Archaebacteria

Most consumer bacteria are classified by the thickness of their cell wall. We test to see the thickness with a Gram-stain.

We do this to determine what kind of antibiotic we have to use to destroy the bacteria.

Archaebacteria

These are called ancient bacteria, and are mostly anaerobic. They live in swamps, intestines and very extreme conditions, like hot springs and high salt lakes.

We use these bacteria to process sewage, because they feed on methane gas.

Good Bacteria Sec 7-2H.W. pg 201 ques. 1-4

We live symbiotically, with a lot of different types of bacteria. Meaning be benefit from having them in our environment.

Some bacteria live inside your intestine and help you to digest. They also produce vitamin K.

We also use bacteria to produce some antibiotics, like streptomycin.

Bacteria and the environment

If bacteria didn’t decompose dead materials, then the Earth would be filled with dead animal, plants and other material.

These bacteria, that live off of dead or decaying material are called saprophytes.

Also, plants and animals need to intake nitrogen to survive. Bacteria take nitrogen from the air and convert it into a form that plants can use directly. They are called nitrogen fixing- bacteria.

Bacteria and food

We use bacteria to make food products every day.

We add cultures of bacteria to milk in order to make cheese. The bacteria eat the lactose in the cheese and produce enzymes that cause the milk to curdle, so we can press it into cheese.

We use bacteria to make other things like antibiotics, glues and cleansers.

Bad bacteria

Some bacteria can infect you and cause disease. These are called pathogens.

We can inhale them, eat them, get them through cuts in our skin.

Once in your body they divide and multiply at a very fast rate, and infect and destroy cells.

They destroy cells by producing toxins, or poisons that cause the cell to die.

Bad bacteria

Botulism is food poisoning cause by a bacteria that, if not handled properly could result in death or paralysis.

Some bacteria, in in an environment they don’t like, will produce a thick, protective covering called an endospore, until conditions become favorable again.

Once they are favorable the bacteria will begin to infect and kill cells.

Pasteurization

This is how we kill these bad, disease causing bacteria.

We heat food, like milk, to very high temps for short periods of times to kill any harmful pathogens.

Ex: 500 degrees for 15 seconds.

Treating Bacterial diseases

We treat bacterial infections with a variety of antibiotics, that we make from fungi or other bacteria.

The antibiotics target and destroy the cell wall or membrane of the bacteria, and cause it to break open and die before it can reproduce more bacteria.

Some times we can use vaccines to protect against infections.

Test on Chapter 6 in one Week!!!!! H.W. pg 207 ques 1-10