Kingdoms. Basic Branches of Life More than 200 years ago, Linnaeus began with only the Plant and...
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Transcript of Kingdoms. Basic Branches of Life More than 200 years ago, Linnaeus began with only the Plant and...
Kingdoms
Basic Branches of Life
More than 200 years ago, Linnaeus
began with only the Plant and Animal
Kingdoms.
Later Kingdoms Protista, Fungi, and
Monera were added.
Recently the Kingdom Monera was
divided into two kingdoms (Archae
and Eubacteria),
According to scientific theory, the earth is
approximately 4.5 billion years old.
According to fossil records, bacteria has been on the
earth for 3.5 billion years – it is the oldest known
organism.
Prokaryotic Cells
Where did the FIRST cell come from?
No one was present to observe this event, so we
really don’t know; what we do know is nobody has
ever created a cell from scratch in the chemistry lab.
Kingdom Archaebacteria (Archae)
Tiny prokaryotic cells, less than 2 micrometers in size
All live without oxygen; they obtain energy from inorganic
molecules or light
Live in extreme environments and include
Methanogens – methane producing, live in marshes,
swamps and guts of animals
Halophiles – salt loving – live in salt pools and seas
Thermophiles – live in hot springs and volcanoes
Acidophiles – acid loving – live in volcanoes
Volcanic vents on the sea floor
Chemosynthetic bacteria use the sulfur in the “smoke” for energy to make ATP.
The red color of this snow is due to a blue-green bacteria
Kingdom Eubacteria
By far the more successful kingdom of bacteria
Today, it accounts for most of the prokaryotic cells
on earth.
Typical Bacteria Cell
Structure Function
Cell Wall Protects and gives shape
Outer Membrane Protects against antibodies (Gram Neg. Only)
Cell Membrane Regulates movement of materials, contains enzymes important to
cellular respiration
Cytoplasm Contains DNA, ribosomes, essential compounds
Chromo-some Carries genetic information
Plasmid Contains some genes obtained through recombination
Capsule & Slime
Layer
Protects the cell and assist in attaching cell to other surfaces
Endospore Protects cell against harsh environments
Pilus Assists the cell in attaching to other surfaces
Flagellum Moves the cell
Anatomy of a Bacterial Cell
1. Cell envelope (the glycocalyx, cell wall and cell membrane)
a. Glycocalyx
Substance secreted on the surface
Outside cell wall
Usually sticky
not found in all bacteria
loosely attached types are called slime layer
mucoid, sticky types firmly bonded to the cell are called a
capsule
both types of glycocalyx can also be antigenic and
stimulate the production of antibodies needed for the
body to eliminate bacteria with these structures from the
body
Glycocalyx
Both types of glycocalyx can benefit bacteria by:
allowing better attachment to various surfaces, even when
smooth
biofilms on medical devices like pacemakers, catheters,
IUDs, also on industrial filters and pipes, plaque
helping to prevent the dehydration of the bacterium
helping to prevent the attachment of bacteriophages
serving as a storage depot of nutrients inhibiting phagocytosis
by white blood cells
this increases the pathogenicity (bacteria with capsules are
usually noted to be more pathogenic than the same species
without capsules)
Figure 4.11
Fimbriae
Fimbriae short non-locomotor appendages used to
attach bacteria to various surfaces
No Nucleus-DNA in Cytoplasm
Classification of Bacteria
1.) Morphology- involves shape, size, appearance &
structure
A.) Bacteria have 3 predominant shapes:
Basic shapes:
i.) Cocci (pleural)
Coccus (sing.)
Sphere shaped
Cocci bacteria
ii. Bacillus (sing.), bacilli (pleural) – rod shaped
Bacillus bacteria
iii.) Spiral Bacteria (spirillium)
Spirillum Spirochete
Vibrio
Spirillium bacteria have a corkscrew shape
Spirillium bacteria
b.) Arrangements
Single: micrococci,
monococci
Pairs: Diplococci,
diplobacilli
Clusters: Staphylococci
Chains: Streptococci,
streptobacilliFigures 4.1a, 4.1d, 4.2c
diplococci bacteria
Ex. causes gonorrhea
staphylococci bacteria
ex. causes common
infections of cuts
streptococci bacteria
Ex. causes some types of sore
throats
Diplobacilli bacteria
Streptococci bacteria
Staphylococci bacteria
The tip of a needle.
The red and yellow dots are bacteria.
C.) Other structures – ex. flagellum or cilia?
Figure 4.7
D.) Average size: 0.2 -1.0 µm in diameter and 2 - 8 µm
in length
Bacteria are very small
This is a pore in human skin and the yellow spheres are bacteria
Bacteria are very small compared to cells with nuclei
Bacteria compared to a white blood cell that is going to eat it
Bacteria
Skin has about 20 million bacteria per inch2