It’s a research document about different type of infectious diseases and is taught in BTEC Applied Science Unit 12. It’s a DISTINCTION level work. It’s referenced in Harvard style and is in Word format.
Aims of this assignment
The aim of this report is to know:
• What is infection and diseases?
• What is the difference between them?
• How can we get diseases?
• What condition do they need to survive?
• What is the difference between communicable and non-communicable diseases?
• What is pathogen?
An infection is the invasion of an organism's body tissues by disease-causing agents, their
multiplication, and the reaction of host tissues to the infectious agents and the toxins they
produce. An infectious disease, also known as a contagious disease or communicable disease, is
an illness resulting from an infection. Infections are caused by infectious agents including:
bacteria, virus, fungi, parasite and more...[22] Agents that cause diseases are called pathogens.
Communicable diseases can spread from an infected person to another, but the non-
communicable diseases do not spread.
Infectious diseases
Bacteria
Bacteria are a type of biological cell. They constitute a large domain of prokaryotic
microorganisms.[2] Bacteria are among the smallest living things. A single bacterium consists of
just one cell, and is called a single-celled, or unicellular organism.[1] They exist in their millions,
in every environment, both inside and outside other organisms.[5]
“Bacteria are thought to have been the first organisms to appear on earth, about 4 billion years
ago. The oldest known fossils are of bacteria-like organisms. Bacteria can use most organic and
some inorganic compounds as food, and some can survive extreme conditions.” A growing
interest in the function of the gut microbiome is shedding new light on the roles bacteria play in
human health. [5]
They are a type of biological cell. They constitute a large domain of prokaryotic microorganisms.
Typically, a few micrometers in length, bacteria have a number shapes, ranging from spheres to
rods and spirals. [2]
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,Assignment 12A Ajmal Shekeb Noormal
Spherical: Bacteria shaped like a
ball are called cocci, and a single
bacterium is a coccus. Examples
include the streptococcus group,
responsible for “strep throat.”
Rod-shaped: These are known as
bacilli (singular bacillus). Some
rod-shaped bacteria are curved.
These are known as vibrio.
Examples of rod-shaped bacteria
include Bacillus anthracis (B.
anthracis), or anthrax.
Spiral: These are known as spirilla
(singular spirillus). If their coil is
very tight, they are known as
spirochetes. Leptospirosis, Lyme
disease, and syphilis are caused by bacteria of this shape. [5] [3] figure 1, bacterial shapes
Even though it is just a single cell, it can carry out all seven life processes (movement,
respiration, sensitivity, growth, reproduction, excretion, and nutrition).[1]
There are similarities between plant and animal cells and a bacterium. They all share a cell
membrane and cytoplasm. Bacterium also have a cell wall around them, like plant cells. However,
unlike most plant and animal cells, it has no nucleus. Instead, it has a circular strand of DNA,
called a plasmid, that floats in the cytoplasm.[1] Here is a picture of bacteria structure:
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,Assignment 12A Ajmal Shekeb Noormal
[4] figure 2
There are millions of distinct types of bacteria. Different types of bacteria have different shapes.
Many types of bacteria have extra cell structures to help them to survive. For example, they may
have: Flagella, which are tail-like structures that allow bacteria to move through liquids, or A
slime capsule, outside the cell wall, to protect them and stop the bacterium drying out.[1] (see
figure 2).
Bacteria can be found in soil, water, plants, animals, radioactive waste, deep in the earth’s crust,
arctic ice and glaciers, and hot springs. There are bacteria in the stratosphere, between 6 and 30
miles up in the atmosphere, and in the ocean depths, down to 32,800 feet or 10,000 meters
(about the height of Mount Everest) deep.[5]
Not all bacteria are harmful. For example, Bacteria in the digestive system break down nutrients,
such as complex sugars, into forms the body can use. Non-hazardous bacteria also help prevent
diseases by occupying places that the pathogenic, or disease-causing, bacteria want to attach to.
Some bacteria protect us from disease by attacking the pathogens.[5] Gut bacteria help to digest
food. They also help to prevent diabetes, obesity, and some types of cancer.
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, Assignment 12A Ajmal Shekeb Noormal
Bacteria are also useful in foods, for example, yoghurt and cheese makers use bacteria to make
their products.[1]
Some bacteria cause diseases, which are called pathogens (any small organism, such as a virus or
a bacterium that can cause disease [6] ), including food poisoning, meningitis, and scarlet fever.
Inside the body, these bacteria reproduce quickly. They produce poisons that make you feel ill.[1]
There are many kinds of bacterial diseases. These are some of the most Infectious and Deadliest
Diseases Caused by Bacteria:
1) Anthrax: a severe infection caused by the rod-shaped, Gram-positive bacterium Bacillus
anthracis. Anthrax comes in three forms: lung anthrax or pneumonia, skin anthrax, and intestinal
anthrax. All these forms can result to death if not treated immediately.[7]
2) Tetanus: is a fatal bacterial infection that affects the brain and the nervous system. It is caused
by the bacterium Clostridium tetani that produces a toxin that paralyzes muscles. This infection
can cause the spasms and even respiratory difficulties.[7]
3) Leptospirosis: is a bacterial infection that can be obtained when the eyes, nose, or an open
wound is exposed to soil or water that is contaminated with the bacteria. This bacterium is
commonly found in animal urine. When left untreated, this infection can damage the kidney,
liver, lungs, and even the brain. In worst cases, it may cause death.[7]
4) Tuberculosis: is a highly contagious disease that infects the lungs. Its symptoms include fever,
weight loss, night sweats and persistent cough that may last for many months. TB is an airborne
pathogenic bacterium that can be transmitted from one person to another via sneezing and
coughing.[7]
5) Cholera: is a type of bacterial disease that is often characterized by watery diarrhea and severe
dehydration. When left untreated, it can lead to death. This infection is caused by consuming
water or food that is contaminated with the bacterium.[7]
If the human body is exposed to bacteria that the body does not recognize as helpful, the immune
system will attack them. This reaction can lead to the symptoms of swelling and inflammation
that we see, for example, in an infected wound.[5]
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