Viruses, Biotechnology, And Genome Evolution

Question 0

What may a viral genome look like?

Answer 0

They may be double or single stranded DNA. They may also be double or single stranded RNA. The genome is organized into a single linear or circular molecule.

Question 1

What is a virus? Are they considered living or nonliving?

Answer 1

An infectious particle consisting of little more than genes packaged in a proteins coat. They are nonliving.

Question 2

What is a capsid?

Answer 2

The protein shell enclosing the viral genome.

Question 3

What is the viral envelope?

Answer 3

A membrane, derived from membranes of the host cell that cloaks the capsid.

Question 4

What is the host range?

Answer 4

Host specificity due to evolution of recognition systems. Lock and key fit between the virus and host cell.

Question 5

Describe the viral replicative cycle.

Answer 5

Infection begins when virus binds to host cell and it’s genome enters the host. The viral genome reprograms the host cell to copy the viral nucleic acids and manufacture viral proteins. Once viral nucleic acids and capsomeres are produced they spontaneously self assemble into a new virus. 100’s to 1000’s of viruses exit the host cell and are now capable of infecting other host cells, spreading the infection.

Question 6

What is a retrovirus?

Answer 6

RNA animal viruses.

Question 7

What is a vaccine? What does it do to the immune system?

Answer 7

A vaccine is a harmless variant or derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen. The immune system begins producing antibodies specific to that virus.

Question 8

What are the two routes of transmission for plant viruses?

Answer 8

1. Horizontal Transmission

2. Vertical Transmission

Question 9

What is the difference between an epidemic and a pandemic?

Answer 9

An epidemic is a general outbreak of a disease. A pandemic is a global epidemic.

Question 10

Can viruses evolve? If so, how?

Answer 10

Yes, they evolve through transposons, mutations, and reassortment/exchange of genes.

Question 11

What is DNA fingerprinting and when is it used?

Answer 11

A technique used to identify individuals based on short pieces of DNA. It is used in criminal cases, confirmation of identity, and paternity.

Question 12

What is polymerase chain reaction (PCR)?

Answer 12

Technique used to generate large concentrations of a DNA fragment. It is used to compare genomes at a single locus for biological studies/forensic analysis.

Question 13

What is gel electrophoresis?

Answer 13

A technique used to separate fragments of DNA or proteins based on size.

Question 14

What is a genetically modified organism (GMO)?

Answer 14

An organism that has acquired, by artificial means, one or more genes from another species or another variety of the same species.

Question 15

Why might crops be genetically modified?

Answer 15

To increase nutritional value, supply essential nutrients to people in underdeveloped nations.

Question 16

What is gene therapy?

Answer 16

Introducing genes into an afflicted individual for therapeutic purposes. The gene is replaced or supplemented with a normal, functioning gene.

Question 17

Why is gene therapy not a routine method for treatment of disease?

Answer 17

Does not seen to have lasting effects. May have to be treated several times. Risk of severe immune response. Viral vectors often attacked immediately.

Question 18

What is the difference between gene cloning and animal cloning?

Answer 18

Gene cloning is the production of multiple copies of a single gene. Animal cloning results in an identical organism.

Question 19

What is a cloning vector?

Answer 19

A DNA molecule that can carry foreign DNA into a host cell and replicate there.

Question 20

What is a transgenic animal?

Answer 20

A gene from an animal of one genotype is introduced I to the genome of another individual, often a different species.

Question 21

What is a totipotent stem cell? Pluripotent stem cell?

Answer 21

A totipotent stem cell can give rise to any embryonic or adult tissue. A pluripotent stem cell can give rise to many, but not all, parts of an organism.

Question 22

What is the relationship between the complexity of the organism and noncoding DNA?

Answer 22

Low gene density means high percentages of noncoding DNA in humans.

Question 23

What is a pseudogene?

Answer 23

Former genes that have accumulated mutations and are no longer functional.

Question 24

Would you expect closely related species to have very similar genomes or very different genomes? Why?

Answer 24

Very similar due to divergence.