BIO101 Exam 3

Where did AIDS come from? How did the first human get it?

From a chimpanzee. Likely through blood contact while butchering a monkey with a cut.

Prokaryotes existed for how long?

Over 2.5 billion years.

How many have died from AIDS?

13 million.

What is the Binomial System of Nomenclature?

A system of naming species with two names: Genus and species. Example: Homo sapiens. Developed by Carl Linnaeus.

Who developed the Binomial System?

Carolus Linnaeus.

What is Taxonomy?

The science of classifying living organisms based on shared characteristics and evolutionary history.

Mnemonic for Taxonomic Categories?

Dumb Kids Playing Catch On Freeways Get Smashed (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species).

How to properly write a scientific name?

Italicized or underlined. Genus is capitalized, species is lowercase. Example: Escherichia coli.

What is a Species?

A group of organisms that can interbreed and produce fertile offspring.

Differences between Bacteria, Archaea, and Protista?

Bacteria: Prokaryotes with peptidoglycan cell walls. Archaea: Prokaryotes without peptidoglycan; live in extreme environments. Protista: Eukaryotic, mostly unicellular, diverse lifestyles.

What are Methanogens and where do they live?

Archaea that produce methane. Found in anaerobic environments like swamps, cow guts, deep-sea vents.

How do bacteria reproduce?

Binary fission (asexual reproduction). “Bacterial sex” = conjugation (DNA exchange via pilus).

Key bacterial structures and functions?

Pilus: DNA transfer & attachment. Glycocalyx: Sticky coating. Cell wall: Structure & support. Flagella: Movement.

How do some bacteria survive harsh conditions?

They form endospores, resistant to heat, radiation, and drying.

Are all bacteria pathogens?

No, most are harmless or beneficial. Examples of pathogens: Yersinia pestis, Mycobacterium tuberculosis.

What was Earth's atmosphere like 2.5 billion years ago?

No oxygen; mostly methane, ammonia, CO₂, water vapor.

What are the most abundant living organisms on Earth?

Bacteria, especially in the ocean and soil.

Are viruses alive?

No. They can't reproduce on their own, have no metabolism, and require a host cell.

Can viruses infect any cell?

No, they are host-specific. Some infect bacteria (bacteriophages).

What is the Endosymbiotic Theory?

Eukaryotic cells evolved when a larger cell engulfed a smaller one. Mitochondria and chloroplasts have their own DNA, double membranes, and reproduce like bacteria.

How are protists categorized in class?

Based on type of movement.

Types of protist movement?

Amoeba: Pseudopodia. Flagellates: Flagella. Ciliates: Cilia. Sporozoans: No movement.

What are Apicomplexans and what diseases do they cause?

Parasitic protists with no movement. Cause malaria (Plasmodium), cryptosporidiosis, toxoplasmosis.

Disease-causing protists and the diseases?

Giardia – Giardiasis; Entamoeba – Amoebic dysentery; Plasmodium – Malaria; Cryptosporidium – Diarrhea; Trypanosoma – African sleeping sickness.

Bacteria that cause human diseases?

Yersinia pestis – Plague; Neisseria gonorrhoeae – Gonorrhea; Chlamydia trachomatis – Chlamydia; Mycobacterium tuberculosis – Tuberculosis.

What is HIV and AIDS?

HIV (Human Immunodeficiency Virus) causes AIDS (Acquired Immunodeficiency Syndrome). HIV attacks helper T cells (CD4+).

How to prevent HIV?

Safe sex, clean needles, avoid blood contact, antiretroviral drugs.

What other animals are infected by the flu?

Birds, pigs, horses, dogs. Cross-species infection can lead to new strains (e.g., swine flu).

What are the three types of body plans?

Acoelomates: No cavity (flatworms); Pseudocoelomates: Fake cavity (roundworms); Coelomates: True cavity (humans, earthworms).