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