Diseases unit

What are microorganisms?

Single-celled, microscopic organisms

Who discovered microorganisms?

Anton van Leeuwenhoek

What are the two main classifications of microorganisms?

Prokaryotes and Eukaryotes

What are prokaryotes?

Single-celled organisms without a nucleus (bacteria + archaea)

What are eukaryotes?

Organisms with cells that contain a nucleus

What are the 3 domains of life?

Bacteria, Archaea, Eukaryotes

Where are bacteria found?

Everywhere (soil, water, air, and inside the body)

Are most bacteria harmful?

No, most are beneficial

What are probiotics?

Beneficial bacteria that improve health (e.g., yogurt)

What is normal flora (indigenous microbiota)?

Helpful bacteria living in/on your body

Functions of normal flora?

Digest food Produce vitamins (K, B12) Remove toxins Protect against pathogens

What are archaea?

Prokaryotes with unique biochemistry

What are extremophiles?

Organisms that live in extreme environments (e.g., high heat)

What are hyperthermophiles?

Archaea that live in extremely high temperatures

What are stromatolites?

Fossilized layers of ancient microorganisms

Why are stromatolites important?

Evidence of early life and oxygen production

How do scientists determine fossil age?

Radioactive isotope dating

Are viruses considered alive?

Usually no (not cell-based)

What is a virus made of?

DNA or RNA + protein coat

What is the lysogenic cycle?

Viral DNA integrates into host DNA and replicates with it

What are the 7 characteristics of life?

• Contains DNA

• Evolves

• Reproduces

• Uses energy

• Made of cells

• Grows/develops

• Maintains homeostasis

What are infectious diseases?

Diseases caused by microbes or parasites

Two types of diseases?

Internal system breakdown (e.g., cancer) Infectious diseases (microbial)

Who linked microbes to disease?

Robert Koch

What did Koch discover?

Specific bacteria cause specific diseases (e.g., anthrax)

What are bacterial colonies?

Groups of bacteria grown from a single cell

What are pathogens?

Disease-causing bacteria

Example of harmful bacteria?

Cholera

What are protists?

Eukaryotic organisms (can be parasitic)

Harmful examples of fungi?

athletes foot and ringworm

Examples of viral diseases?

Influenza, measles, HIV, chickenpox

What is a retrovirus?

Virus that converts RNA → DNA (e.g HIV)

What did John Snow discover?

Cholera spreads through contaminated water, Helped develop modern epidemiology