Bacteria
Bacteria are found everywhere on the earth.
Initially Bacteria were divided into a kingdom called Monera.
However, scientist found out that even though all Bacteria are
unicellular and Prokaryotes (No Nucleus) they are chemically
different. So Bacteria were divided into two kingdoms:
Archaebacteria and Eubacteria.
Kingdoms
Archaebacteria are bacteria that live in extreme conditions. These
Bacteria produce foul odors.
Eubacteria live everywhere but cannot live in extreme conditions.
They help in maintaining some of earth’s physical conditions.
Structure
Bacteria have three different shapes: Rod, Spiral, and Sphere.
Bacterial cell has a Cell wall and a cell membrane. Inside the cell
membrane jello like cytoplasm is present. Since, Bacteria doesn’t
have a nucleus the genetic material is found in the cytoplasm.
Some Bacterium have flagella, a long, whip like structure to move
around. Bacteria that do not have flagella depend on air, water
currents, clothing and other objects to carry them.
Reproduction
Bacteria can reproduce as often as every 20 minutes. Bacteria can
reproduce Asexually and Sexually
Binary fission, where one cell divides into two identical cells is a
form of asexual reproduction. This process forms identical
bacteria.
Conjugation is a form of sexual reproduction where the genetic
material from one bacterium is passed on to other through a thin
thread like bridge. This process results in genetically different
bacteria.
Survival Needs:
Bacteria must have a source of food, a way of obtaining energy
and survival techniques.
Some bacteria are autotrophs and can make their own food while
some heterotrophic bacteria can obtain food by consuming
autotrophs or other heterotrophs.
Bacteria obtain energy from breaking down the food particles and
releasing energy through a process called as respiration.
During, unfavorable conditions bacteria can form an Endospore,
which is small, round, thick walled, resting cell, which has the
cell’s genetic material and some cytoplasm. The Endospore can
survive for many years since it resists freezing, heating and drying
thus, helping the bacterium to survive.
Useful and Harmful Bacteria.
1: Methane produced by Archaebacteria is a major component of
Earth’s deposit of natural gas.
2. Activities of helpful Bacteria provide foods like yogurt, cheese,
and apple cider.
3. Decomposers break down large chemicals into smaller
chemicals and thus return basic chemicals to the environment.
4: Bacteria help to clean up Earth’s land and water. ( Bacteria
convert dangerous chemicals in oil into harmless substances.
Bacteria can cause infectious diseases like strep throat, a disease
that can be passed from one organism to another.
Antibiotics are used to cure bacterial diseases which helps to kill
the bacteria without harming a person’s own cells.
See if you can answer the questions below.
Questions:
1:What Process results in genetically different bacteria?
2: What is found in the cytoplasm of Bacterial cells?
3: What are the Shapes that describe a bacterial cell?
4: When do endospores form?
5: What is an endospore and what is its role in a bacterium?
5: What is the process called when food is broken down to release
energy?
6: What important role do Decomposer bacteria play?