Download Microbiology Study Guide

Microbiology Study Guide
The Scientific Process
*Steps: Observe, Research, Question, Hypothesize, Run experiment with controls and variables, Collect data,
Conclusion, Return to observation if results do not support hypothesis.
*Hypotheses are educated guesses, and should be written as an answer to your question, such as:
I think that ______________________, because of _________________________. OR
If ______________________________, then ______________________________.
They should never be written as a question.
*Controls are things that remain the same while running an experiment. Everything should be controlled except
for one type of thing, the thing that you are testing.
*Variables are the things that you change during the experiment to test if it changes the outcome, such as testing
altitude, location, or temperature. There should be only one type of variable in each experiment.
*A conclusion is a statement written after running an experiment based on the findings and data collected.
Microbiology
*Organisms are living things.
*There are 6 Kingdoms of Life: Animal Kingdom, Plant Kingdom, Fungus Kingdom, Protist Kingdom, and
Two Bacteria Kingdoms
*Microorganisms, or microbes, are living things that can only be seen with the aid of magnification.
*Microorganisms include bacteria, fungi, protozoans and algae.
*Microorganisms are both helpful and can be harmful.
Bacteria
*Bacteria are microscopic, single-celled organisms that exist all around you and inside you.
*They can cause sickness and disease, such as strep throat, food poisoning, and cholera. Understanding this has
taught us to do things such as wash our hands before eating.
*Bacteria are also very important to life on Earth. We depend on bacteria to help in the digestion of food, for
plant growth, and to help us make foods and medicines.
*Bacteria play a very important role as decomposers in our ecosystem; bacteria and fungi feed on and break
down plant and animal matter, including the bodies of all organisms that have ever lived.
*When you eat yogurt or cheese, you eat bacteria.
*Bacteria are some of the smallest microorganisms. You can see them when there are thousands growing
together in a colony. To see a single bacterial organism requires a microscope with high magnification.
*Scientists culture bacteria, or grow microorganisms. Bacteria like warm, moist places.
*There are three shapes of bacteria. They are spiral-shaped, rod-shaped, and sphere-shaped.
Fungi
*Fungi are organisms that are neither plant nor animal, yet have characteristics of both.
*Fungi absorb food from whatever source they are growing on.
*Some fungi are large enough to see without a microscope.
*Examples of fungi are mushrooms and yeast.
*Yeast is used to make bread rise and give it flavor. Bubbles of gas form in the dough.
*A type of fungus causes athlete’s foot.
*They like warm, moist places to grow.
Protists
*Examples of protists are algae, and protozoa such as euglena, paramecium, and amoeba-like protozoa.
*They are microscopic organisms that often live in ponds.
*Euglena, paramecium and protozoa are all single-celled organisms with a nucleus and other cell parts.
*Many protozoa move by themselves, unlike other microorganisms.
Protists continued:*The paramecium moves through the water with tiny hair-like arms called cilia that are
located all around the body and wave back and forth to move it through the water.
*The euglenas contain chlorophyll to make their own food, and have one long hair which they use to propel
themselves by whipping it around.
*The amoeba-like protozoa move by extending pseudopodia, or false feet.
*Giardia is caused by protozoa that live in streams and ponds.
*Algae can make their own food. They grow in water. Some are very large, while others are microscopic.
Some of the largest algae are kelp.
*Algae provide food for fish, whales and many other sea animals.
*Algae are also eaten by people. Algae are used to thicken ice cream.
Food Preservation Techniques
*Bacteria and other microorganisms can grow in food that is not protected by any kind of preservative.
*Some preservatives, or food additives, are sugar, salt, corn syrup and vinegar. They slow the growth of
microbes.
*Other techniques for food preservation are: canning, drying, freezing, pasteurization, pickling, vacuum
packaging, and chemical additives. They also slow the growth of microorganisms on your food.
Important Discoveries and their Scientists
*In 1928, Alexander Fleming was working with bacterial cultures, studying staphylococci bacteria, and
accidentally left a plate by the open window for a few days. When he returned he found mold growing on the
staphylococci. There was a clear zone that existed around the mold. It was killing the deadly bacteria.
Penicillin was that mold. His mistake gave the world penicillin, an antibiotic, which is now considered one of
the greatest discoveries of the 20th century. He received the Nobel Prize in 1945, and millions of people
worldwide have survived disease because of his discovery.
*Louis Pasteur was a French chemist. He is sometimes known as the father of modern bacteriology, because he
was able to show that bacteria exist, grow and can be controlled. He developed an investigation based on a
question, a hypothesis, an experiment with controls and variables, observations and a conclusion, the Scientific
Method. He discovered that heating does kill bacteria. He developed the process of pasteurization (heating food
to a high temperature for a short time to kill bacteria).
Viruses
*Viruses are not made up of cells. They are not alive so they are not found in a kingdom of life.
*They get inside a host cell, and then direct the cell to produce new virus particles. The new ones are released
and can infect other cells which can cause diseases such as Hepatitis A or the common cold.
*Because they are not alive, antibiotics cannot kill them. Taking antibiotics won’t cure the disease caught.
HIV or AIDS
*HIV is the virus that causes AIDS which stands for Acquired Immune Deficiency Syndrome.
*AIDS prevents a person’s body from fighting off other diseases by attacking the immune system.
*AIDS is spread by having sex with someone who is infected with HIV, by sharing needles with an intravenous
drug user who has HIV; a mother with HIV can pass the virus to her baby before or during birth, and there is
almost 0% chance of spreading it through receiving infected donated blood.
*There are reported cases of AIDS in every age group, but you can avoid getting AIDS by never sharing things
that have someone else’s blood on it, like razor blades. Tattooing, body piercings, and becoming blood
brothers/sisters are high risk activities.
*Once you are infected with the HIV virus, it remains inside your body. It may take 10 years before symptoms
are seen or felt and it becomes the AIDS disease. People may not even know they are infected, and during that
time, they could still spread the virus to others.
*There is no vaccine or medicine that will prevent you from getting AIDS, and there is no cure.