KINGDOM ARCHAEA and KINGDOM BACTERIA

KINGDOM ARCHAEA
These organisms can survive in extreme conditions where no other organisms can survive.

Examples:

a) They may reside near hot springs and sea floors of the ocean where
temperatures are 100oC.
b) In alkaline (basic) or acidic waters
c) In saline solutions like that of the Dead Sea
d) In volcanoes and on hot lava

All these organism live without the presence of O2
They look like bacteria but are very different biochemically and genetically.

Summarize pages 414- 418 on Archaea make sure that you know specific names of different types and where they can be found



KINGDOM BACTERIA

All bacteria are prokaryotes
Are single celled organisms
Some of these bacteria may live in a linked up structure/chain to form filaments and some live together in colonies


Bacteria are classified by 3 main criteria:
a)Shape
b)Structure of the cell walls
c)Source of food & energy

Other methods of classification:
d) Staining properties. (i.e. gram positive or gram negative)
e) Conditions needed for growth
f) Appearance of colonies


a)SHAPE (pg. 420)

When we look at the organism and it consists of a single cell, shape is very important in identifying them. There are three basic shapes:

Cocci – round (singular coccus)

Baccilli – rod shaped (singular bacillus)

Spirilli – spiral-shaped (singular spirillum)

Each shape gives bacteria different advantages.
(e.g. pg 420) Figures 12.5 and 12.6

Draw a diagram for diplo, staphlo, and strepto. Then define each term pg. 420
Cell Wall Structure (pg. 421)

Bacteria differ in the structure and thickness of their cell walls.
There are basic differences in arrangements of amino acids and sugar molecules.

b)Gram Stain

These technique was developed by Hans Gram
It is a stain that is used on bacteria that has the ability to show the difference in the cell walls.
Gram Positive bacteria: a positive bacterium has a thick protein layer and stains the colour purple.
Gram Negative bacteria: a negative bacterium has a thin layer and will stain the colour pink. This group is larger and more diverse.

See figure 12.7 on pg. 421for stains.
Draw diagram of gram-stains on pg. 427 figure12.14


c)Carbon and Energy Sources

See handout for pg. 421
Copy word link on pg. 421 for other ways to identify and classify bacteria based on differences in their metabolism:



How Bacteria Reproduce

ASEXUAL REPRODUCTION:

Since bacteria lack a nucleus, mitosis and meiosis cannot occur.
Reproduction of bacteria in this case must occur through binary fission
Bacteria contain a single chromosome which holds it’s genetic information
This single chromosome replicates, the bacteria grows, elongates and separates the 2 chromosomes.
The cell then builds a partition between the two chromosomes and the original cell splits into 2 smaller identical cells.

This method is very fast and a bacteria cell can divide in 20 minutes.
The two new bacteria both multiply again and so on, and so on.
A single cell can become 30,000 cells in only 5 hours.

See figure 12.9 pg. 424.


SEXUAL REPRODUCTION:

In less favorable condition some bacteria are able to reproduce sexually. This is called conjugation.

A) Bacteria cells become linked to one another through building structures called
Pili (singular: pilus)

B) One bacteria transfers all or part of its chromosome to the other bacteria
across the pilus.

C) The receiving cell then undergoes binary fission.

See figure 12.10 pg. 425


GENE TRANSFER:

The genes that are transferred above are found in plamids.
These are small loops of DNA that are separate from the main chromosome.
Plasmids contain from one to a few genes.
They can split from the bacterial chromosome and rejoin it.

Draw figure 12.11 pg. 425.


BACTERIAL DIAGRAMS:

The diagrams shown here are used to help name and distinguish types of bacteria from one another.

The first picture are actual shots of what bacteria look like under a microscope, while the other two photographs were taken under the microscope but where stained to ensure what type of cell memebranes that they had.


























Above is a photo of some gram negative simple bacillius bacterium.)












Above is a photo of a gram positive stain turned purple on the outer cell wall of some anthrax bacterium.)

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