Unit 4 Flashcards
(19 cards)
Ligase
Repairs nicks by linking sugars through bonds with phosphate groups.
DNA Polymerase III
Extends the new strand by attaching complementary nucleotides to the template DNA.
DNA Polymerase I
Removes the primer and replaces it with DNA nucleotides.
Topoiosmerase
Relieves super-coiling upstream of the origin of replication.
New strands of DNA are synthesized in which direction?
5’ to 3’
Meselson and Stalh’s experiments proved that DNA replicates by which mode?
Semi-conservative
The ends of a chromosome are protected by the presence of
Telomeres
The enzyme helicase
Separates the 2 DNA strands of the double helix
Which would you expect of a eukaryotic organism lacking telomerase
a reduction of chromosome length in gametes (I’m not 100% sure on this one)
A poly-A sequence is added at the:
3’ end of transcribed mRNA in the nucleus
How many nucleotides are in 12 mRNA codons?
36
The AUC and AUA codons in mRNA both specify isoleucine. What features of the genetic code explains this?
the tRNA wobble
Which best describes introns?
untranslated DNA sequences in a gene
What is often the first amino acid added to the polypeptide chain?
Methionine
What are the RNA components of ribosomes called?
rRNA
An organism displays evolutionary advantage through fitness. Which of the following would not be considered an example of a trait (generic or otherwise) that positively contributes to fitness?
A dog acquires an infection as a pup that damages it’s olfactory system.
Image that you work in a lab running an early drug trial for a new antibiotic. When testing the medication on lab mice no cytotoxicity is discovered. However, when the drug is brought to clinical trials, a safety signal is discovered that indicates the drug may cause heart damage in humans. Based on your understanding of the potential issue of your lab mice having significantly longer telomeres than their wild counterparts, which is the most likely conclusion?
The longer telomeres in mice allow the mouse to recover quicker from cellular injury. Combined with our data from clinical trials, we should investigate the drug more intensely as it relates to cytotoxicity at large throughout the body as cardiac tissue is more likely than other tissues to signal for damage of this kind due to a low rate of mitosis.
Which of the following acts as an initiator sequence in transcription?
An RNA primer sequence (Also not sure bat this one either)
Spliceosomes are responsible for splicing
exons together after the removal of introns from the RNA
