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Honors Biology
Module 2
Kingdom Monera
Part 2
September 12, 2013
Class Challenge
Your favorite Sports team:
Super Fan
Questions from Homework?
Quiz: ID the 3 Basic Shapes of
Bacteria
Quiz
Identify as Asexual Reproduction or
Sexual Reproduction
4. The offspring is a genetic copy of the
parent. ___________
5. Each parent contributes to the DNA, and
the offspring’s DNA is a blend of parents’
DNA. ____________
6. Once the cell wall and plasma membrane
elongate, and separate the copy cell
(daughter cell) from the original, two cells
are now created.
What is this an example of ?
== == ==
4. Asexual
5. Sexual
6. Asexual Reproduction
Genetic Recombination in Bacteria
When bacteria reproduce asexually, the
offspring is a genetic copy of the parent.
However, when bacteria exchange genetic
information in order to increase the genetic
diversity of the population in one of three
ways:
1. Conjugation
2. Transformation
3. Transduction
Conjugation
Figure 2.6
Is a temporary union of two organisms for
the purpose of DNA transfer.
Plasmid- a small, circular section of extra
DNA that confers one or more traits to a
bacterium and can be reproduced
separately from the main bacterial genetic
code.
The first step in conjugation among bacteria
involves the donor grasping the recipient with its
sex pili. Sex pili are also fimbriae that re used in
reproduction.
The donor bacterium is the one that initiates
conjugation. Once the donor grasps the
recipient, a conjugation tube is formed
between the bacteria. Then the donor bacterium
transfers one of the plasmid’s strands to the
recipient.
Bacteria Conjunction
• https://youtu.be/EtxkcSGU698
Transformation
Is the transfer of a DNA segment from a
nonfunctional donor cell to that of a function
recipient cell.
If a bacterium dies, its cell wall falls apart and the
components of the cell (including the DNA) flow
into the surroundings. The dead bacterium’s
DNA seems to break into small; pieces and the
living bacterium might “sense” that on or more of
those pieces contains a trait or traits it could use.
So the living bacterium then absorbs what it
needs, incorporating the new genetic information
as a plasmid.
Transformation in Bacteria
https://youtu.be/MRBdbKFisgI
Once a bacterium has such a plasmid, it
might then engage in conjugation to pass
the plasmid on to other bacteria.
Transduction
Is the process in which infection by a virus
results in DNA being transferred from one
bacterium to another.
So a virus can pick up DNA from a
bacterium during infection and that DNA
can be inserted into another bacterium in a
subsequent infection.
Genetic Transfer - part 1 (4:52)
http://youtu.be/t4i0Q_irM8o
Genetic Transfer - part 2
http://youtu.be/XPvuc9j1t-k
Transduction
• https://youtu.be/An9oItt7U9I
Bacterial Colonies
Figure 2.7
The bacteria’s ability to survive is usually
enhanced when they form a colony.
There are 3 basic shapes of bacteria
1. Coccus (spherical)
2. Bacillus (rod-shapped)
3. Spirillum (helical)
Bacterial Colonies
A bacterial colony is just a simple
association of individual bacteria.
Each bacteria could survive on its own if
separated.
Some colonies will secrete a capsule-like
substance that surrounds and protects the
entire colony. It is slimy and holds the
colony together. (Stagnant ponds often
have the look of floating mats on top of the
water.)
Bacterial Colonies
Some colonies work together to capture and eat
prey. When they find it, they engulf it and as a
group secrete a substance that digests it. The
entire colony then feeds on the nutrients.
They can be found in soil, are thin rod shaped,
gram-negative cells that exhibit self-organizing
behavior as a response to environmental cues.
The swarm, which has been compared to a "wolfpack," modifies its environment through
stigmergy.
This behavior facilitates predatory feeding, as the
concentration of extracellular digestive enzymes
secreted by the bacteria increases.
Myxococcus Xanthus Colony
Classifying Kingdom Monera
Bacteria is so diverse, we will only be
dividing it into two different phyla’s :
Using the Gram Stain, certain bacteria look
blue under the microscope, while others
looked red. (see figure 2.8)
Now this is used to classify bacteria.
See Table 2.1
on page 55.
Partial Classification of Kingdom Monera
Classifying Bacteria
If the bacteria has a cell wall that doesn’t retain the
Gram stain (making it Gram Negative – Red
stain), it belongs to phylum Gracilicutes.
Three Classes:
1. Scotobacteria: non-photosynthetic (Lyme and
many other pathogenic bacteria)
2. Anoxyphotobacteria: photosynthetic that do not
produce oxygen. (live in sediments of lakes or
rivers.)
3. Oxyphotobacteria: photosynthetic bacteria that
produce bacteria. (blue-green algae)
Bacteria that have a cell wall that retains the
Gram stain (making them Gram-positive
– Blue stain) belong to phylum
Firmicutes.
Two Classes separated by their shapes:
1. Firmibacteria: containes cocci and bacilli
2. Thallobacteria: spirillum (helical) shaped
Bacteria that has no cell wall are in phylum
Tenericutes.
One class:
1. Mollicutes: contains pneumonia-causing
bacteria.
.
Lastly, bacteria possess cell walls, but the
compounds which form these walls are rather
different from the compounds that form the cell
walls of Gram-positive and Gram-negative
bacteria. They are in a separate phylum
Mendosicutes
One Class:
Archaebacteria: has all the bacteria with exotic
cell walls (live in deep ocean vents, brackish
seas like the Great Salt lake) Many places that
are uninhabitable to other organisms are
populated with members of this class.
Conditions for Bacterial Growth
1.
2.
3.
4.
5.
Moisture
Moderate temperature
Nutrition
Darkness
The proper amount of oxygen
Remember there is a great diversity among
bacteria and these conditions are only the
most important conditions for bacterial
growth.
Bacteria is generally very specialized in
terms of their habitat.
Preventing Bacterial Infections
1. Food becomes infected as it is exposed
to the air. What is in the air?
2. What can you do to prevent bacterial
growth on food?
Think about the conditions that
promotes bacteria’s growth…
1.
2.
3.
4.
5.
Moisture
Moderate temperature
Nutrition
Darkness
The proper amount of oxygen
1.
2.
3.
4.
5.
6.
Cover the food and seal it.
Heat or cook the food
Refrigerate it
Dehydrate
Freeze
Pasteurization (milk)
How about if you cut yourself?
What should you do to help fight infection
(bacterial growth)?
Experiment 2.2
Pond Life, Part B
Homework
1.
2.
3.
4.
5.
6.
7.
Complete On Your Own Questions
Complete Study Guide Questions
Complete Experiment 2.2 in Lab book
Take Module 2 Test
Read Module 3 p.67-79
Class challenge: Guy Harvey Day
Quiz: ID: Conjugation, Transformation, and
Transduction; The 5 conditions that promote
bacterial growth; Name and Draw the 3 shapes
of bacteria.