Transcript Structures and Functions of Living Organisms

Structures and Functions of
Living Organisms
8.L.1
Understand the hazards caused by agents of
disease that affect living organisms
Structures and Functions of Living
Organisms
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8.L.1.1
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Summarize the basic
characteristics of
viruses, bacteria, fungi
and parasites relating
to the spread,
treatment and
prevention of disease
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8.L.1.2
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Explain the difference
between epidemic and
pandemic as it relates
to the spread,
treatment and
prevention of disease
Diseases
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Disease
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A condition that prevents the body from
functioning properly
Agents of Disease
Agents of Disease
Not a “Fun Guy”
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Many diseases in humans are caused by
microorganisms
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Living thing that can not be seen without a
microscope
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Also called microscopic
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Needs to be seen with a microscope
Microbiology is the study of these organisms
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Includes the study of viruses, bacteria, protozoa, and some
fungi
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single-celled organisms with animal-like behaviors
Agents of Disease
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Fungus
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One-celled or many-celled organisms
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Most that cause disease are one-celled
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Many-celled fungi do not usually cause disease
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Such as Yeasts, molds, and mildew
Such as mushrooms and shelf fungi
Fungi cells are similar to plant and animal cells
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They have a nucleus and membranes
Agents of Disease
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Parasite
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An organism that lives on or in another
organism and benefits at the other organism’s
expense
Uses the tissues or fluids of the host as a
food source
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Organism on which it lives
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Can weaken or sicken the host
Agents of Disease
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Virus
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Microscopic core of genetic material surrounded by a
protein coating
Causes illness when they infect a living cell
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Viruses are not living organisms
Not made up of cells
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Do not carry out any functions of life except reproduction
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Must infect a living cell to reproduce
Examples above are Ebola and Flu
Agents of Disease
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Bacteria
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One celled organisms (prokaryotes)
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Does not have a nucleus contained in a membrane
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Also lacks other similarities to plant and animal cells
Grouped according to shape
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Spirillum: spiral shape (corkscrew)
Bacillus: rod shaped
Coccus: round or spherical shaped
Fungi and Disease
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Fungi can invade many parts of the body
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Ringworm is a common example
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From skin infections, to more serious
problems with bones, lungs and heart
Neck, scalp, groin or feet
Molds can lead to lung problems such as
allergies, asthma attacks, and pneumonia
Crash Course Video (12 minutes)
Diseases Caused by Parasites
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Most parasites do not kill their host
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If they did, they would lose the benefits of
the host
They use the host of nourishment
This sickens the host
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5 Worst Parasites (3:30 minutes)
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Bacteria and Disease
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Bacteria can be found everywhere
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Water and soil
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All surfaces people touch daily
Some can be useful to break down remains of
dead organisms
Many are pathogens
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Biological agent that causes disease or illness to its
host.
They enter through food and drink, or through cuts
on your skin
Bacteria and Disease
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Once inside the body, they reproduce
quickly
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Can act as parasites once inside the body by
using nutrients
Most cause disease producing poisons that
disrupt normal cell functions
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Examples include cholera, salmonella, pneumonia,
and typhoid fever
Bacteria and Disease
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Many diseases caused by bacteria have been
brought under control through the use of
antibiotics
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Over time, some antibiotics have become
resistant to treatment
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Drugs that kill bacteria or slow their growth
Immune to change
Bacteria Video (4:30 Amoeba Sisters)
Viruses and disease
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Viruses are not living
Some examples of diseases they cause are:
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Smallpox, chickenpox, measles, AIDS, and the flu
(influenza)
To reproduce, they infect a host cell, deposit
genetic material, create new virus, then burst
out of the cell, killing the cell and starting the
process over
Viruses and Disease
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Often produce aches and fevers
Antibiotics do not work to destroy
them
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Scientists are working on antiviral
substances
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Drugs that slow down the rate at which the virus
reproduces
Virus Rap (4 minutes)
Public Health
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Real life scientists are working to control
the spread of diseases
But not this…
Keeping People Healthy
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Public health is the science that deals with
protecting and improving the health of the
people in the community
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They make sure that food, water, and medicines are
safe
Scientists develop and test new medicines
Some are disease detectives
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They research diseases and look for ways to prevent them
They study how pathogens function
They look for ways to prevent and predict the spread of
diseases
Disease Detectives (4 minutes)
Widespread Diseases
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Infectious Diseases
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Diseases that can be passed from one
organism to another
The common cold, chickenpox, measles, and
AIDS
Some spread more easily than others
Widespread Diseases
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Two classifications:
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Epidemic
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An outbreak that affects many people in an area
Pandemic
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An epidemic that spreads over a larger area or over the
whole
world
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Stopping them can be very difficult
Can vary in length of time and have occurred
throughout history
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Epidemics and History (3:35 minutes)
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Infectious Diseases in Plants and
Animals
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Many diseases in plants are caused by
fungi
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Wheat rust and corn smut
Cattle are affected by a disease called
Hoof-and-mouth disease
Can be costly to farmers
Epidemics can reduce food supplies
Vectors
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Vectors
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An organism that transmits a disease
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Malaria is an example
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Caused by a parasite in the blood transferred by mosquitoes
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Mosquitoes also transmit Yellow Fever and West Nile disease
Ticks can be vectors of Lyme disease
Avoid these diseases by avoiding the vectors
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Use bug repellant and wear long clothes
Preventing Infectious Disease
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Good hygiene is a primary way to avoid
infectious diseases
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Wash hands frequently
Bath regularly
Cover your mouth when you cough or sneeze
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Avoid contact with hands
Another way is to kill the pathogens
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biological agent that causes disease or illness to its
host
Preventing Infectious Diseases
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Your body naturally can kill many pathogens
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The immune system
Vaccines can also prevent pathogens
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A weakened or dead form of the pathogen
Stimulates the immune system to make antibodies
that destroy the pathogen
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Large Y-shaped proteins recruited by the immune system to
identify and neutralize foreign objects like bacteria and
viruses
Preventing Infectious Diseases
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CNN Vaccine debate (5 minutes)
Small Pox Vaccine History (6 minutes)
Polio Vaccine History (3 minutes)