DNA & Processes
DNA strands, like the lanes in a road, are called _________ because they are the same but in opposite directions.
Antiparallel - 5' to 3' in one way, 3' to 5' in the other direction
What type of cells can undergo DNA Recombination?
Prokaryotes
What does Genetics mean?
the study of heredity
Can a virus have both DNA and RNA?
nope - either one or the other
The DNA nucleotide is made of 3 things: a sugar, a phosphate group, and a _____?
A nitrogenous base
- Adenine, Thymine (Uracil in RNA), Guanine, and Cytosine
What special body part does a bacteria use during Conjugation?
Pilus
what is a phenotype?
the physical, observable characteristics of an organism (genetic behavior and looks etc)
True or False, a virus can replicate it's own DNA/RNA.
No! that's why it counts as a particle, and not a living thing. That's also why it needs a host cell to hijack.
Name at least 2 characteristics of a virus
acellular, an infection particle, obligate intracellular parasite, teeny tiny, etc.
What attaches the complementary base pairs in DNA (what holds the two strands together)?
Hydrogen bonds.
Three between Cytosine and Guanine,
Two between Thymine and Adenine,
___________ is when a bacteria picks up free DNA from the environment and absorbs it into its own chromosome.
Transformation
What is a Reading Frame shift?
when a mutation occurs and changes the reading frame of DNA, which changes the entire meaning of the rest of that DNA strand.
Far worse than a Point mutation.
what are the four types of genomes/nucleic acid formations that a virus could have?
ssDNA, dsDNA, ssRNA, dsRNA
Name at least two viral capsid shapes
Helical and Icosahedral (both can be naked or enveloped)
What happens in between Transcription and Translation? What are the players involved?
mRNA editing/processing:
snRNP's make up spliceosomes that cut out Introns, leaving only the Exons (exons are expressed), which will then continue on to the Ribosome for Translation.
Explain the differences between Transduction and Transposition.
Transduction is when a virus in a host cell accidentally includes some of the cell's DNA with its own genetic material. Thus when it infects a new cell, the new cell gains some new DNA from the original cell.
Transposition is when a gene can hop around within a cell, from the chromosome to a plasmid and back again.
What type of gene can be turned off by the product of that gene? (when the gene is made, it binds to the beginning of the gene and stops the gene from getting transcribed - what is this called)
(like histine)
What types of viruses are classified as positive/negative sense? What does this mean?
single stranded RNA viruses.
If they are negative sense, they have to make the other side of the RNA first before they can make proteins/go to ribosome (using RNA dependent RNA polymerase enzyme) OR they can use Reverse Transcriptase (RT enzyme) to turn itself into DNA which will then enter the nucleus and undergo transcription/translation as normal.
Positive sense can immediately enter a ribosome and undergo translation. They could have Reverse transcriptase or RNA-dep-RNA-poly, but don't need either.
Give an example of Cytopathic effects and describe what happens to the cell
4 options:
- inclusion bodies (mass buildup in organelle, nucleus, etc)
- Syncytia/giant cells (cells fuse when infected and this makes them become one huge multi-nucleated cell)
- Cell lysis (it pops!)
- alter the cell's DNA/Transformation (can cause cancer: more growth, infinite division, altered chromosomes)