Bacteria (bacterium) are prokaryotic, one-celled organisms occurring alone or in a chain. Remember that a prokaryote is a cell without a defined nucleus, or a nuclear membrane.
Where do they live?
air, food, and drink
surfaces of the things we touch
Some live in extreme environments (Archaea):
hot springs
hydrothermal vents (temperatures rise above 100 degrees C)
Dead Sea (high in salt)
Coal Mines (pH of 1)
Structure:
The genetic material is found in a single chromosome in the cytoplasm.
A thick gelatin capsule and a slime layer surround the cell to help it stick to surfaces and retain water.
Bacteria ARE living!!
They are composed of cells!
Bacteria are capable of reproducing on their own.
SHAPE: There are 3 distinct shapes that describe all bacteria:
Bacilli (Rod shaped)
Cocci (Spherical shaped)
Spirilli (Spiral shaped)
Arrangement: In addition to living on their own, they can also live in three basic arrangements:
Di = pairs
Strepto = chains EX: strep throat
Staphylo = clusters EX: staph infection
Reproduction: Fission:
asexual reproduction
cell splits asexually into two identical bacteria
DNA is replicated
Cell splits into two identical cells
Sexual Reproduction:
DNA is exchanged between two bacterial cells
GOOD BACTERIA: Natural consumers & recyclers (Saprophytes)
Many bacteria break down dead organisms as food and an energy source
some break down sewage wastes into carbon dioxide and water
Nitrogen-fixing bacteria
Medicine:
Vaccines: made from damaged or dead particles
Antibiotics: limit the growth of other bacteria Penicillin - prevents bacteria from making cell walls to protect itself
Bioremediation:
using bacteria to clean up or remove environmental pollutants
Bacteria in us:
many types of bacteria live naturally in your intestines
they help you digest food and produce vitamins you need such as vitamin K for blood clot formation
Bacteria in Food:
yogurt
breaks down substances in milk to make dairy products like cheese and buttermilk
vinegar, pickles, olives, and soy sauce are examples of food make with the help of bacteria!
HARMFUL BACTERIA:
Pathogens - any organism that causes disease
Bacterial pathogens can cause strep throat, whooping cough, diphtheria, tetanus, and anthrax in cattle.
Some bacterial pathogens produce poisonous substances called toxins. Ex: Botulism - a type of food poisoning
Pasteurization - process of heating food to a temp that kills most harmful bacteria but causes little change to taste of food.
FUNGI
FUNGI are NOT plants because they cannot produce their own food in the absence of chlorophyll.
Fungi grow best in moist and warm environments.
Examples of fungi are mold, mushrooms, yeast, lichens, and truffles.
A common fungus that shows up as a skin infection is
ringworm. (Tinea)
athletes foot
jock itch
PARASITES
lives ON or IN an organism of another species known as the host
obtains nutrients from the host
keep the host alive as long as possible
usually don't destroy major organs first
benefit from the host, but harm the host (parasitic relationship)
Flatworms are found in the intestines of many vertebrates. This is a problem because they will obtain the nutrients from the food eaten by the vertebrate, keeping the nutrients from their host.