Lecture 2 Flashcards by Abteen Mirpour

Which organisms are able to thrive almost everywhere (including places too acidic, salty, cold, or hot for most other organisms)?

Prokaryotes

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What are some key differences between prokaryotes and eukaryotes?

PROKARYOTES

They have smaller cell sizes (smaller in diameter)
They usually have no membrane, other than the cell membrane, which may be unfolded.
The DNA is not contained in a discrete region.
Small genome.
Presence of few organelles (ribosome being one of them)

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Are eukaryotes more ancient or prokaryotes?

Prokaryotes

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Most prokaryotes are _____, although some species form colonies.

Unicellular

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What are the different shapes for prokaryotes?

Spheres-Spiral-Cylinder. SSC

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What is the cell wall of eukaryotes made of?

Chitin or cellulose

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What do bacterial cell walls contain?

Peptidoglycan, a network of sugar polymers cross-linked by polypeptides.

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Which of the domains contains polysaccharides and proteins but lacks peptidoglycan?

Archaea

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What is responsible for targeting peptidoglycans and damaging bacterial cell walls?

Antibiotics

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What does it mean for something to be motile?

It can move.

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How do motile bacteria move?

They propel themselves using the flagella that are structurally and functionally different from eukaryotic flagella.

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Define Taxis. When does it happen?

Taxis is the ability to move toward or away from certain stimuli; it happens in a heterogenous environment.

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What are characteristics of prokaryotes evolving and reproducing?

They can reproduce very quickly by binary fission and divide every 1-3 hours.

They can evolve rapidly due to their short generation times.

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Do prokaryotes or eukaryotes have considerable genetic variation? What are factors attributed to this?

Prokaryotes; the three factors are rapid reproduction, mutation, and genetic recombination.
RMR. (Reproduction-Mutation-Recombination)

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In what ways can prokaryotic DNA from different individuals be brought together?

Transformation-Transduction-Conjugation. TTC

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Define Transformation

A prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment in a process called transformation.

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Define Transduction

The movement of genes in between bacteria by bacteriophages (viruses that infect bacteria)

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Define Conjugation

Occurs when genetic material is transferred between two bacterial cells that are temporarily joined.

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Define Phototrophs

Obtain energy from light.

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Define Chemotrophs

Obtain energy from chemicals.

Define Autotrophs

Require CO2 as a Carbon source.

Define Heterotroph

Requires an organic nutrient to make organic compounds.

What are the 4 major modes of nutrition?

Photoautotrophy-Chemoautotrophy-Photoheterotrophy-Chemoheterotrophy

What is an example of a photoautotroph?

Cyanobacteria

What is an example of a chemoautotroph?

Sulfolobus

What is an example of a photoheterotroph?

Rhodobacter

What is an example of a chemoheterotroph?

Clostridium

What are heterocysts?

Photosynthetic cells and nitrogen-fixing cells that exchange metabolic products.

Where does metabolic cooperation occur in some species of prokaryotes?

Surface-coating colonies called biofilms.

What, generally, is the role of prokaryotes in the biosphere?

They play a major role in the recycling of chemical elements between the living and non-living components of the ecosystems.

How do prokaryotes function as decomposers?

Chemoheterotrophic prokaryotes function as decomposers, breaking down corpses, dead vegetation, and waste products.

What do nitrogen-fixing prokaryotes do for the environment?

They add usable nitrogen to the environment which is then used by plants.

Define Symbiosis

An ecological relationship in which two species live in close contact: a larger host and a smaller symbiont.

What are the different types of symbiosis?

Mutualism-Commensalism-Parasitism. MCP

Define Mutualism

A symbiosis in which both symbiotic organisms benefit.

Define Commensalism

One organism benefits while neither harming or helping the other one in any significant way.

Define Parasitism

An organism called a parasite harms but does not kill its host.

Define Pathogens

Parasites that cause disease.

_____ cause about half of all human diseases.

Prokaryotes

How do pathogenic prokaryotes cause disease?

By producing endotoxins and exotoxins.

How do Exotoxins behave?

They can cause disease even if the prokaryote that produces them are not present.

How do endotoxins behave?

They are released only when bacteria die and their cell walls break down.

What does the Fimbriae do in prokaryotes?

It’s a sticky hair-like structure that allows it to adhere (stick) to things.

What does the Sex Pilus do in prokaryotes?

It is a hollow tube that allows for the transfer of DNA.

How is the movement of the rod of prokaryotes driven?

By a proton pump

In conjugation, how do you know which one is the host cell and which one is the donor cell?

The DONOR CELL contains the plasmid. DP

In all the possible symbiotic reactions, what happens to the symbiont?

It always BENEFITS.

How can prokaryotes be beneficial in our lives?

They can be used to make more ethanol to use for fuel and they can make things from the products of prokaryotes.