Unit 8: Pathogens

EQ- How do viruses, bacteria, protists, and fungi interact with people?

Topic: Unit 8: Pathogens

Microorganisms

Disease causing Bacteria, Viruses, Fungi and Parasites are often microscopic and may infect the human body and interfere with normal body functions.

Multiple Choice

How does our body fight off most attacks from harmful bacteria or viruses?

• by not touching anything with possible bacteria or viruses on them

• the bodies defense mechanisms, our immune system, fight off most

• the bodies vestigial structure, the appendix, fights off harmful microbes

Pathogens:

Viruses, harmful bacteria, harmful fungi and harmful protists (parasites) that cause infectious disease

EXAMPLES:

● Pneumonia---Can be a virus, bacteria or fungus

pathogen

● Influenza---Comes from a virus pathogen
● Common Colds---Comes from a virus pathogen

Multiple Select

Choose all of the example of pathogens below.

• viruses

• bacteria

• fungi

• keratin cells

• parasites

Types of Pathogens:

EXAMPLES:

● Bacteria- single celled, prokaryote, simple
● Viruses- nonliving, needs a host
● Fungi- unicellular or multicellular, complex, heterotroph
● Protists- parasite or needs a host

Infectious Disease:

illness caused by pathogenic organisms that enter and
reproduce inside the body

EXAMPLES:

● Pneumonia
● Influenza
● Common Colds

Multiple Choice

What are TWO ways a disease can be transfered or spread?

• through running and eating contaminated foods

• through direct contact and eating contaminated foods

• through exercise and direct contact

Bacteria:

● Single celled organisms
● Can live in many different environments (with

oxygen, without oxygen, extreme heat, extreme
cold)

● Antibiotics are used to inhibit (prevent/slow down)

the growth of bacteria

○ Antibiotics have been overused causing antibiotic

resistance

Multiple Choice

What can be used to help fight off a bacterial infection?

• antibiotics

• antiviral

• vaccines

Viruses:
● Non-living particles composed of a nucleic acid

(DNA or RNA) and a protein coat

● Must have a host to reproduce

● They invade a host cell, reproduce and bust open

the cell, killing it before moving on to a new cell

● These are among the most widespread illnesses

in humans!

● Vaccines and antiviral pharmaceuticals are used

to control and prevent viral diseases

Multiple Choice

What is one main difference between a virus and bacteria?

• they are both microscopic

• one is considered living and one must have a host to reproduce

• one is only found in certain countries in the world, while the other is found worldwide

Fungi:
● Can sometimes attack the tissues of living plants

and animals and cause disease

● Because fungi can attack human food sources, it

makes them competitors for nutrients

Fungi:

Ringworm:

Athlete’s Foot:

Parasites:

● Feeds on another individual, known as a

host

● They are specialized to for their lifestyles

○ EXAMPLE: Tapeworms don’t even have a

digestive system, they simply zap nutrients from
their hosts through their skin while living in the
small intestines

Key Concept

You can get pathogens that cause human disease in four different ways.

1) One way you can get pathogens is by direct contact with a sick person.

For example, if you shake hands with a sick person, you may pick up pathogens on your hands.

Cold viruses can spread this way.

Another way you can get pathogens is by eating food or drinking water that has pathogens in it.

Food poisoning can spread ths way.

You can also get pathogens from dirty water and/ or soil.

You can get pathogens by using objects -- such as towels or silverware-- that a sick person has used.

• Flu viruses can spread this way

• Covid-19 can spread this way

Finally you can get pathogens from animals.

• For example, you can get bacteria that cause Lyme disease from ticks.

• These tiny ticks pass the bacteria to people with they bite them.

• Mosquitoes can pass on Malaria (mostly in very hot climates).