Download Aseptic Technique: Media and Equipment

Growth

Human Terms:
Growth = __________

Microorganism Terms:
Growth = __________
Growth

Binary Fission – bacteria reproduce
__________ :
 Chromosome __________
 Cell __________
 Plasma membrane __________ in at center
 __________ __________ distributes evenly
 Cell wall thickens to separate dividing cells
Growth
Binary fission – gives __________ to
bacteria
 The first bacterium ________ _______
 It __________ and becomes a new,
young cell again
 The original __________ (billions of
years old) is still among us

Growth
Reproduction:
__________ __________
20 Generation
21 Generation
22 Generation
23 Generation
Generation Time

Time between _______ __________
when bacteria grows and develops its
unique features

Also called “________ _________”

A determining factor in the __________ of
time that passes between entry of an
organism into our bodies and the
__________ of disease symptoms
Growth

Each microorganism has it’s own
characteristic __________
__________

Range:



Usually 1 to 3 __________
__________ 20 minutes (E. coli)
__________ 33 hours (T. pallidum syphilis)
BACTERIAL GROWTH IS
LOGARITHMIC
Growth
Growth Rates

If after 48 hours of __________, a
colony is pinpoint size, __________ GT
is indicated.

If after 48 hours, the __________ is ¼”
wide, __________ GT is indicated.
Growth Example
E. coli has a 20 minute __________ __________
under ideal conditions:
Time
# of Bacteria
0
1
1 hour
8
2 hours
64
3 hours
512
10 hours
> 1 billion
36 hours
Cover face of the earth
Growth
Growth Rates

Exponential growth signifies ideal
__________ and maximum __________

But the __________ __________ of
bacteria is never fully realized due to
environmental __________
Growth Phases
Many dynamics __________ the
population of bacteria over the course of
__________
 A certain population’s history may begin
when:

 Several bacteria enter the __________
__________ tract
 Several bacteria are transferred to a tube of
__________ __________ in a lab
Growth Phases
Lag Phase:

First few hours of __________ __________

Period of __________ to new environment

If an __________, WBC’s can be
__________ some cells

If in a lab, some cells may die from
__________ __________
Growth Phases

The activity of the remaining cells is
intense as they:
 Store __________
 Synthesize __________
 Prepare for __________ __________

But the curve remains at a __________,
where the number of cells reproducing
__________ the number of cells dying
Growth Phases
Log Phase:

Also called “__________” phase

The mass of each cell increases
__________ and __________ follows

As each generation time passes, the
number of bacteria __________ and the
graph rises __________
Growth Phases

In humans, disease symptoms arise during
the __________ __________
 Bacterial population is high enough to
__________ __________
 Fever, __________, tissue damage arise

In a lab, visible signs of growth will be seen:
 colonies will appear on ________ ________
 broth media will become __________
Growth Phases

Research experiments are usually done
during the __________ __________
because the population of bacteria is at
its __________ __________
Growth Phases
Stationary Phase:

Period of __________ __________
numbers

Reproduction rate = __________
__________

No change in total number of __________
Growth Phases
Stationary Phase:
 In humans:

 the __________ __________ may be destroying
the bacteria
 antibiotics have been __________

In the lab:
 nutrients are becoming __________
 __________ __________ are building up
 oxygen or water could be in __________
__________
Growth Phases
Decline Phase:
Environment becomes progressively
__________ and exerts its __________
__________


pH is changing

oxygen and nutrients are __________

accumulation of __________
Growth Phases

Decline Phase:

Number of cells __________ __________
the number of new cells formed

Spore forming species will start to produce
__________

Flagellated species will try to __________ to a
new location

For other species, culture death is __________
Things That Affect Growth
Temperature

Different species grow at different
temperatures
 __________ – grow best between 0oC and
20oC
 __________ – grow best between 20oC and
40oC
 __________ – grow best between 40oC and
90oC
Things That Affect Growth
Temperature
Most bacteria are __________,
especially __________ __________ that
grow in the human body (37oC)
 When the body’s temperature rises to
40oC (104oF) there is a slightly
_________ affect on bacterial ________
 The lab incubator is set at 37oC to
__________ bacterial growth

Things That Affect Growth
Temperature
Some __________ can grow at refrigerator
temperatures and cause __________
__________
 Staphylococci can grow in the refrigerator
and deposit their __________ on cold cuts,
salads and leftovers
 If these foods are eaten without further
cooking, __________ __________ can result

Things That Affect Growth
Temperature
__________ outbreak in a restaurant in 1991
 Restaurant employee prepared Caesar salad
dressing which contains raw egg
 It may have remained at room __________ too
long before being served
 Within 3 days, 15 people were __________
with diarrhea, fever, cramps and __________

Things That Affect Growth
Oxygen
__________ bacteria – require
__________ to grow
 __________ bacteria – require an

oxygen-free environment to grow
 Includes __________ species that cause
tetanus and botulism

__________ bacteria – grow in either the
presence or __________ of oxygen
 includes many staphylococci, streptococci
and bacilli
Things That Affect Growth
pH
Bacteria have a __________ internal
environment
 Will tolerate a pH range of __________
 Human blood and tissues have a pH of
__________
 Provides a __________ environment for
disease causing bacteria to __________

Things That Affect Growth
pH
Certain bacteria are __________ __________
 Useful in the food and dairy __________
 Lactobacillus and Streptococcus produce the
acid that converts:

 milk to __________
 __________ to sour cream
 milk curds to __________

These bacteria __________ __________
__________ to good health even when eaten in
large quantities
Things That Affect Growth
pH
Most bacteria do not grow well under
__________ __________
 Stomach’s __________ __________
prevents disease
 Certain __________ __________ are hardly
ever contaminated with bacteria

 Citrus fruits
 __________
 Tomatoes
Things That Affect Growth
Pattern of Nutrition
 Bacteria
(like us) need:
 __________
 __________ to serve as energy
sources and as raw materials for
synthesis of cell __________
Things That Affect Growth
Pattern of Nutrition

Two patterns for obtaining nutrition:
 __________ – can make their __________ food
using inorganic carbon, water and sun’s energy
 __________ – obtain preformed organic
molecules from the __________ for structural
components and energy
○ __________ – feed exclusively on dead organic
matter such as rotting wood
○ __________– feed on living organic matter such as
human tissues
Things That Affect Growth
Bacterial Cultivation

In the lab, bacteria are grown in:
 __________ __________ containing water,
beef extract and peptone (protein
supplement)
 __________ __________ – contains the
same, plus agar, a polysaccharide derived
from marine algae
*Most bacteria __________ __________ in
these
Things That Affect Growth
Bacterial Cultivation
Some bacteria require __________ or
__________ media
 The streptococci that cause strep throat and
scarlet fever grow well when __________
__________ is added to the media
 __________ __________– heated before
solidification to disrupt the red blood cells and
release __________
 Sometimes called __________ __________

Things That Affect Growth
Bacterial Cultivation

__________ __________– contain ingredients
to __________ the growth of certain bacteria in
a mixture while __________ the growth of
others
 __________ salt agar – high salt content
__________ the growth of most bacteria, but allows
for staphylococci to grow
 __________ methylene blue agar – contain dyes that
__________ Gram-positive bacteria, but __________
growth of Gram-negative
Things That Affect Growth
Bacterial Cultivation
__________ __________– makes it easy to
distinguish colonies of one organism from
__________ of another on the same plate
 MacConkey’s agar contains __________
__________ as well as lactose

 Colonies of bacteria that __________ __________
are red
 Colonies of bacteria that __________ ferment
lactose are colorless
Things That Affect Growth
Bacterial Cultivation

__________ __________– not
chemically defined
 Exact components and quantities are not
known
 Some bacteria will only grow on natural
media

__________ __________ - chemically
defined
 The nature and amount of each component
is known
Things That Affect Growth
Intermicrobial Relationships
__________ – situation in which two
populations of organisms interact in a
__________ and __________
association
 Benefits obtained may involve:

 food
 __________
 support
Things That Affect Growth
Intermicrobial Relationships
__________ – symbiosis that benefits
both populations
 Bacteria living on roots of plants:

 Bacteria trap __________ for plants to
synthesize __________ __________
 Plants provide a __________ environment
and __________ __________ for bacteria
Things That Affect Growth
Intermicrobial Relationships
__________ – one population receives
benefit from the relationship while the
other is not __________ or __________
 Bacteria that inhabit human skin:

 __________ has a place to live and food
 We are not helped or __________ in any
way
Things That Affect Growth
Intermicrobial Relationships
__________ – two populations live
together and accomplish what neither
could alone
 __________ __________ – two
populations of bacteria (usually rods and
spirochetes) must be present for
__________ of the __________
__________ to occur

Things That Affect Growth
Intermicrobial Relationships
__________– symbiosis is beneficial to one
population (__________) but harmful to the
other (__________)
 The bacteria of all human diseases are
__________

Applications

Industrial: __________ __________
products





Penicillin
Wine
Beer
Alcohol
Vinegar
Pickles
 Cheese


Medical: Phases of disease parallel
__________ __________ of pathogen