Chapter 17
1
VOCABULARY
 Aerobic respiration
 Fermentation
 Antibiotic
 Motility
 Antiseptic
 Mutation
 Bacterial culture
 Prokaryote
 Binary fission
 Resistant/resistance
 Conjugation
 Classification
 Disinfectant
 Ecological role
2
READING
 Basic structure of prokaryotic cell – p.360-361
 Unifying characteristics – p.361-364
 Form, distribution, motility, ecological role, nutrition,





human diseases – p.361-366, 369-372
Fermentation, aerobic respiration, photosynthesis in
Monerans – p.365-367
How bacterial decomposers and parasites obtain their
food – p.365
Antibiotics, disinfectants, antiseptics – p.374
Antibiotic resistance – p.368
Beneficial roles – p370-372
3
THE FIVE
KINGDOMS
4
Introduction to Bacteria
2 TYPES OF BACTERIA:
•Bacteria
-Get food from an outside source
•Blue-green Bacteria
-Make their own food
5
BACTERIA
Bacteria - small one celled monerans
Bacteria like a warm, dark, and moist environment
They are found almost everywhere:
-water
-soil
-skin
-air
-food
-inside the body
-on most objects
6
3 Shapes of Bacteria
Bacteria are classified by shape into 3 groups:
Spiral:
spirilla
rod-shaped: bacilli, bacillus
Round:
cocci
7
3 Shapes of Bacteria
Bacillus anthracis – (bacillus)
Neisseria meningitidis (coccus)
Leptospira interrogans – (spirilla)
8
7 Major Structures of a Bacteria Cell
•Capsule
•Cell wall
•Ribosomes
•Nucleoid
•Flagella
•Pilli
•Cytoplasm
9
7 Major Structures of a Bacteria Cell
Capsule
 keeps the cell from drying out
and helps it stick to food or
other cells
10
7 Major Structures of a Bacteria Cell
Cell wall
Thick outer covering that
maintains the overall shape of
the bacterial cell
11
7 Major Structures of a Bacteria Cell
Ribosomes
 cell part where proteins are made
 Ribosomes give the cytoplasm of
bacteria a granular appearance in
electron micrographs
12
7 Major Structures of a Bacteria Cell
Nucleoid
 a ring made up of DNA
13
7 Major Structures of a Bacteria Cell
Flagella
 a whip-like tail that some
bacteria have for locomotion
14
7 Major Structures of a Bacteria Cell
Pilli
 hollow hair-like structures
made of protein
allows bacteria to attach to
other cells.
Pilli-singular
Pillus-plural
15
7 Major Structures of a Bacteria Cell
Cytoplasm
 clear jelly-like material that
makes up most of the cell
16
Bacteria Reproduce Quickly
 In optimal conditions, an E. coli bacteria can double
every 20 minutes.
 The time it takes a bacteria
to double is known as the
Generation time
A Growth Table
Time (min)
0
20
40
# of E. Coli
1
2
4
Time (min)
200
220
240
# of E. Coli
1024
2048
4096
60
80
100
8
16
32
260
280
300
8192
16384
32768
120
64
320
65536
140
160
128
256
340
360
131072
262144
180
512
380
524288
 At just over 6.5 hours you have over
1 MILLION
E. coli.
Imagine that growing on your sandwich
 This type of growth has a special name. It is known as
Exponential growth.
 Exponential growth starts out slow but once it gets
going it grows quickly.
Lets Graph it!
# of E. coli
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Time
# of E. coli versus Time
140000
120000
80000
60000
40000
20000
Time (min)
340
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
0
# of E. coli
100000
Salmonella
 Salmonella has a generation time of about 30 minutes
 It can be found on chicken and can make you quite
sick.
 Luckily it takes about 10 million of them to get sick so
that’s quite a few.
 Lets calculate how long it takes for bacteria to reach
10,000,000 if we have 1000 on our chicken sandwich.
The Special Equation
 There is a special equation to use with exponential
growth
N = N02t/T
 N = is the number of bacteria
 N0 = the number of bacteria you start with
 T = the amount of time it takes to double
 t = the actual time
 In ideal optimal conditions in about 3 days bacteria
could reproduce sooooo much that they would weigh
more than our planet.
Lucky for us
 Lucky for us those conditions don’t usually exist, and a
graph of bacterial growth generally looks like this
Reproduction of Bacteria
•Binary Fission- the process of one organism
dividing into two organisms
•Fission is a type of asexual reproduction
•Asexual reproduction- reproduction of a living thing from only one parent
How?...
The one main (circular) chromosome makes a
copy of itself
Then it divides into two
29
Reproduction of Bacteria
BINARY FISSION
Bacteria dividing
Completed
30
Reproduction of Bacteria
•The time of reproduction depends on how desirable the conditions are
•Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions
•Some can reproduce every 20 minutes
(one bacteria could be an ancestor to one million bacteria in six hours)
31
Bacterial Cell & Nucleiod DNA Ring
DNA replication
Cell wall synthesis
Cell separation
32
Bacteria Survival
Endospore•a thick celled structure that forms inside
the cell
•they are the major cause of food poisoning
•allows the bacteria to survive for many years
•they can withstand boiling, freezing, and
extremely dry conditions
•it encloses all the nuclear materials
and some cytoplasm
33
Bacteria Survival
Bacillus subtilis
Endospore-the black section in the middle
highly resistant structures
can withstand radiation, UV light, and boiling at 120oC for 15 minutes.
34
Bacteria Survival – Food sources
parasites – bacteria that feed on living things
saprophytes – use dead materials for food (exclusively)
decomposers – get food from breaking down dead matter into simple chemicals
important- because they send minerals and other materials back into the
soil so other organisms can use them
35
Harmful Bacteria
• some bacteria cause diseases
•Animals can pass diseases to humans
Communicable Disease –
Disease passed from one organism to another
This can happen in several ways:
•Air
•Touching clothing, food, silverware, or toothbrush
•Drinking water that contains bacteria
36
Harmful Bacteria
Human tooth with accumulation of bacterial plaque (smooth areas) and calcified
tartar (rough areas)
37
Helpful Bacteria
•Decomposers help recycle nutrients into the soil for other organisms to grow
•Bacteria grow in the stomach of a cow to break down grass and hay
•Most are used to make antibiotics
•Some bacteria help make insulin
•Used to make industrial chemicals
38
Helpful Bacteria
E.coli on small intestines
39
Helpful Bacteria
•Used to treat sewage
Organic waste is consumed by the bacteria,
used as nutrients by the bacteria, and is no
longer present to produce odors, sludge,
pollution, or unsightly mess.
•foods like yogurt, cottage & Swiss cheese, sour cream, buttermilk are made from
bacteria that grows in milk
40
Controlling Bacteria
3 ways to control bacteria:
1) Canning- the process of sealing food in airtight cans or jars after killing bacteria
•endospores are killed during this process
2) Pasteurization- process of heating milk to kill harmful bacteria
3) Dehydration- removing water from food
•Bacteria can’t grow when H2O is removed
•example: uncooked noodles & cold cereal
41
Controlling Bacteria
Antiseptic vs. 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
42
BLUE-GREEN BACTERIA
Autotrophs – make their own food
through photosynthesis
larger than most bacterial cells
commonly grow on water and surfaces that stay wet…such as rivers, creeks and dams
Some live in salt water, snow, and acid water of hot springs
food source for animals that live in the water
43
BLUE-GREEN BACTERIA
can be toxic to humans and animals
Blooms- occur when the bacteria multiplies in great
numbers and form scum on the top of the water
44
45
Bacillus anthracis - rod, vegetative stage
prokaryote (bacterium)
Image Number: 21185A
46
Neisseria meningitidis - coccus prokaryote
(bacterium)
Image Number: 97214E
47
Leptospira interrogans spiral shaped
prokaryote (spirochete)
48