Exam 2 Flashcards
What are some of the advantages of doing independent research, internships, etc., during your years as an undergraduate student?
(1) Hands on research experience
(2) Field specific problem solving and exposure to the research process
(3) Ability to explore and experience your future interests
(4) Connecting with other students with similar research
(5) Professional networking and connection building
(6) You get paid!
What is the significance of the science behind inserting a mouse eye gene into a fruit fly and it producing a healthy, compound insect eye?
The significance of this study was the finding of two explanations for genetic similarities.
(1) homology: were they passed down from the common ancestor of all these different organisms
(2) analogy: did they all evolve independently through convergent evolution
Are viruses alive?
No, they do not fulfill requirements for a living organism, they are not capable of growth and development, they can’t pass on their DNA (the host cell does that for them) and they are not made up of cells
Why do vaccines (and many other scientific/medical advances) get pushback rom segments of society?
Skepticism of today is rooted in the social movements of the postwar era, which prompted a new generation of parents (and their children) to question environmental contaminants, drugs, doctors, and authority in general.
What are the advantages of vaccines?
he most effective way to prevent the spread of infectious diseases.
Why do vaccines work?
Help your immune system fight infections faster and more effectively.
Define bacteriophage
A virus that infects bacteria; also called a phage.
Describe the significance of the tobacco mosaic virus
The first virus to be discovered ever, leading to research into the many other viruses and the ability to see them (via electron microscope).`
Who was Adolf Mayer?
Discovered the he could transmit TMD from plant to plant by rubbing sap extracted from diseased leaves onto healthy plants.
Who was Dmitri Ivanowsky?
A Russian biologist who passed sap from infected tobacco leaves through a filter designed to remove bacteria.
Who was Wendell Stanley?
An American scientist who crystallized the infectious particle, now known as tobacco mosaic virus (TMV)
Define Capsid
The protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape.
Describe Lytic cycle vs. lysogenic cycle
A type of phage replicative cycle resulting in the release of new phages by lysis (and death) of the host cell
VERSUS
A type of phage replicative cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage, is replicated along with the chromosome, and does not kill the host.
Define Prophage
A phage genome that has been inserted into a specific site on a bacterial chromosome.
Define Retrovirus
An RNA virus that replicates by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses.
Define Reverse transcriptase
An enzyme encoded by certain viruses (retroviruses) that uses RNA as a template for DNA synthesis.
Define Provirus
A viral genome that is permanently inserted into a host genome.
Define vaccine
A harmless variant or derivative of a pathogen that stimulates a host’s immune system to mount defenses against the pathogen.
Describe the life-history of a typical virus.
Attachment, penetration, uncoating, gene expression and replication, assembly and release.
Provide some examples of mobile transposable elements.
Proviruses and endogenous retroviruses
Describe the Spanish Influenza outbreak of 1918. Why was it so deadly?
An exceptionally deadly global influenza pandemic caused by the H1N1 influenza A virus. Because the virus was new, very few people, if any, had some immunity to the disease.
Describe the structure of a typical flagellum.
A supramolecular structure composed of about 20 protein components and divided into three substructures:
(1) the filament (the filament is a helix, which takes on several distinct forms under various conditions)
(2) the hook
(3) the basal body.
Does the flagellum structure represent an example of irreducible complexity?
Yes!
What are the 3 Domains of life?
Bacteria, Archaea, and Eukarya
Define Biosphere
The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.
Give the types of prokaryotes (common shapes)
Spheres, rods, or spirals
Define Peptidoglycan
A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides.
Define Gram Stain
A staining method that distinguishes between two different kinds of bacterial cell walls; may be used to help determine medical response to an infection.
Define Capsule
A dense and well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells.
Define Fimbria
A short, hairlike appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells.
Define Pilus
A structure that links one cell to another at the start of conjugation; also called a sex or conjugation _____.
Describe the different types of Taxis
phototaxis: response to light
aerotaxis: response to oxygen
osmotaxis: response to ionic strength
hydrotaxis: response to water
Define plasmid
A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome
Describe the Nucleoid Region
The region in a prokaryotic cell consisting of a concentrated mass of DNA.
Describe how prokaryotes reproduce using the words transformation, conjugation, transduction, horizontal gene transfer, mutation, endospores
In transformation, a bacterium takes up a piece of DNA floating in its environment.
In transduction, DNA is accidentally moved from one bacterium to another by a virus.
In conjugation, DNA is transferred between bacteria through a tube between cells.
Transposable elements are chunks of DNA that “jump” from one place to another. They can move bacterial genes that give bacteria antibiotic resistance or make them disease-causing.
Why do prokaryotes have high genetic variation?
Mutation, recombination and immigration of genes
What are the 4 categories prokaryotic nutrition and metabolism?
Photoautotrophs, chemoautotrophs, photoheterotrophs, or chemoheterotrophs.
Define and describe the protists as an informal taxonomic group (recall that this group is polyphyletic)
Apart of kingdom Protista
What are the 3 nutrition categories of protists
Photosynthetic, holozoic, and parasites
How does endosymbiosis fit into the evolutionary history of the protists?
The earliest protists evolved from prokaryotes (single-celled organisms)