Prokaryotes, Protists, and Endosymbiosis

Flashcards reviewing key concepts about prokaryotes, archaea, protists, and endosymbiosis, based on lecture notes.

What are pathogenic bacteria responsible for?

Causing human disease.

What is a vector, in the context of diseases like tuberculosis?

The means by which a disease is transmitted, where the human portion is only part of the life cycle.

What is direct tissue invasion, as a mechanism of bacterial illness?

When bacterium invades tissue directly and begins to grow and cause problems within the tissue and cells.

Give an example of direct tissue invasion?

Mycobacterium tuberculosis invading lung tissue and Helicobacter pylori causing stomach ulcers

What does MRSA stand for?

Methicillin Resistant Staphylococcus aureus.

What type of bacterium is Clostridium botulinum?

An anaerobic fermenter that causes botulism.

What are exotoxins?

Toxins secreted by bacterium, created as a result of its metabolic process.

How does cholera work?

Certain vibrio produce exotoxins.

What are endotoxins?

Toxic components that are part of the outer membrane or cell wall of a bacterium; released when the cell dies and breaks down.

Give an example of illnesses caused by endotoxins.

Salmonella and Lyme disease.

Why are archaea difficult to study?

They tend to be adapted to extreme environments and don't grow well in laboratory settings.

Are archaea implicated in human diseases?

Not yet, but likely it is just a matter of time.

What are extremophiles?

Archaean groups that live in extreme environments.

Where are methanogens often found?

Swamps, rice paddies, other watery environments, intestines, and waste water treatment plants.

What do methanogens produce?

Methane.

What is methanobrevivacter smithii?

A methanogen comprising approximately one-tenth of the prokaryotic biomass in our guts.

What are halophiles?

Organisms that can tolerate extremely salty environments.

What are thermophiles?

Organisms that can tolerate extremely high temperatures.

Why is the Kingdom Protista problematic as a group?

It was a dumping ground for organisms that didn't fit into other kingdoms and doesn't represent a monophyletic group.

What does monophyletic mean?

A group of organisms that originates from a single ancestral lineage.

What domain are protists members of?

Eukarya.

Name two ways organisms can obtain nutrition.

Photosynthesis and heterotrophic nutrition.

What are myxotrophs?

Organisms that combine both photosynthesis and heterotrophic nutrition.

What does the endosymbiotic theory explain?

The diversity of protists as well as other groups of organisms.

What are plastids?

Pigment containing organelles, such as chloroplasts.

What is primary endosymbiosis?

The engulfing of a photosynthetic cell, such as a cyanobacterium, by an ancestral heterotrophic cell.

What two single-celled algae are formed as a result of primary endosymbiosis?

Red algae and green algae.

What is secondary endosymbiosis?

The engulfing of red and green algae cells by other cells.

What are the super groups within the domain eukarya?

Excavata, Sarclade, Archaeoplasteda, and Uniconta.

Why is the supergroup Excavata named as such?

Because they have some sort of groove or invagination in their external cell membrane, and very often there are flagella or cilia that stick out from that excavated area.

What does the supergroup Excavata include?

Diplomonids, the parabacillids, the euglenozoans.

What are some characteristics of diplomonids?

Mitochondria that lack electron transport chains, anaerobic pathways, and two nuclei.

What is a well-known diplomonid?

Giardia intestinalis, responsible for giardiasis.

What are euglenids?

Single celled organisms that are myxotrophic.

Why is the super group sarclade named that?

It includes Straminophiles, Alveolates, and Risarians, which is an acronym for 'SAR'.

What does the stramenopiles include?

Diatoms, golden algae, and brown algae.

What does the alveolates include?

Dinoflagellates, apicomplexans, and ciliates.

What do the risarians include?

Forams, cercosoans, and radiolarians.

What are diatoms?

Unicellular algal cells with a cell wall made of hydrated silica.