Bacteria Basics

1
Bacteria Basics
2
Where are bacteria found?
Most bacteria like a warm, dark, and moist
environment, but they are found almost
everywhere -water -air -soil -food -
on your skin -inside the body -on most objects
3
How are bacteria classified?
Bacteria are classified by shape
Spiral-shaped Rod-shaped Round
4
How do bacteria reproduce?

• Bacteria reproduce by binary fission, which is a
  type of asexual reproduction.
• asexual reproduction- reproduction of a living
  thing from only one parent

• binary fission- the process of one organism
  dividing into two organisms
• Fluorescence Imaging of Bacterial Binary Fission
  - YouTube

5

• The time it takes for bacteria to reproduce
  depends on their environment.
• Bacteria reproduce more rapidly in warm, dark,
  and moist conditions.
• Some can reproduce every 20 minutes.
• (At that rate, one bacterium could become one
  million bacteria in six hours.)

6
A key to their survival
Bacteria are able to survive harsh conditions by
forming endospores. Endospore - a thick walled,
protective structure that forms inside the cell
when conditions are unfavorable for survival

• A major cause of food poisoning because it allows
  the bacteria to withstand boiling, freezing, and
  extremely dry conditions

7
Endospore (the black section in the middle)
8
How can bacteria be harmful?

• The wastes produced by some bacteria spoil food.
• Since bacteria reproduce better in warm
  temperatures, it helps to keep food cold.

9

• some bacteria cause communicable diseases
  (diseases passed from one organism to another)
• This can happen in several ways
• through the air
• by touching contaminated clothing, food,
  silverware, toothbrush, etc.
• drinking water that contains bacteria

10
                                                                           1

                                                                           1

                                                                           1

                                                                           1

                                                                           1

Some Bacterial Illnesses

• Food poisoning
• Lyme disease
• Tetanus (Lockjaw)
• Tuberculosis
• Strep throat

11
                                                                           1

                                                                           1

                                                                           1

                                                                           1

                                                                           1

Treatments for Bacterial Infections

• Antibiotics such as Amoxicillin help to cure
  bacterial infections
• Antibiotic ointments and sprays kill bacteria in
  cuts and scrapes

12
How can bacteria be helpful?

• Some bacteria decompose (break down) dead
  organisms, which recycles nutrients into the soil
  for other organisms to use to grow.
• E-coli bacteria grow in the stomach
• of a cow to break down grass and
• hay, and in humans to break down
• high fiber foods.
• Many are used to make antibiotics.

13

• Some bacteria help make insulin to treat
  diabetes.
• Bacteria are used to treat sewage. Organic waste
  is consumed by the bacteria and is no longer
  present to produce odors, sludge, pollution, or
  an unsightly mess.

14

• Help produce foods such as
• Cheese
• Apple cider
• Sauerkraut
• Pickles

15

• Sourdough bread
• Yogurt
• Cottage cheese
• Sour cream
• Buttermilk

16
How can bacteria be controlled?
1) Canning- the process of sealing food in
airtight cans or jars after killing bacteria
2) Pasteurization- process of heating milk to
kill harmful bacteria and then cooling it quickly
3) Dehydration- removing water from food
(Bacteria cant grow when H2O is removed example
uncooked noodles cold cereal)

17
Antiseptics Disinfectants
Antiseptic- chemicals that kill bacteria on
living things

• means against infection

Examples iodine, hydrogen peroxide, alcohol,
soap, mouthwash
Disinfectants- stronger chemicals that destroy
bacteria on objects or nonliving things
18
                                                                           1

                                                                           1

                                                                           1

                                                                           1

                                                                           1

The End