Sollars

Question 1

AAA+ ATPase

Answer 1

– DnaA binds to the origin of replication and disassociates the helical strands. The energy of ATP cleavage is used to produce a conformational change in DnaA, which forces the strands apart

Question 2

DNA Ligase

Answer 2

creates phosphodiester bonds by using the energy of ATP cleavage, this seals “nicks” in the DNA strand

Question 3

DNA Polymerase

Answer 3

these enzymes are responsible for strand elongation, require a ssDNA as a template, and require an RNA primer

Question 4

Helicase

Answer 4

these enzymes cause disassociation of the two strands of the DNA double helix, unwinding the structure using the energy released from ATP cleavage
strand separation

Question 5

Nucleases

Answer 5

sever phosphodiester bonds of the DNA backbone. They can function as an endonuclease or exonuclease

Question 6

Primase

Answer 6

– responsible for synthesizing short stretches of RNA complementary to the template DNA strand that serve as a primer for DNA polymerase

Question 7

Topoisomerase

Answer 7

– these enzymes adjust the supercoiling of DNA double helices, both alleviating supercoiling stress and introducing negative supercoiling. They contain both endonuclease function and ligase fuction. Type I topoisomerases cleave one of the strands of the double helix, Type II Topoisomerases cleave both strands to perform their functions

Question 8

DNA polymerase I

Answer 8

special 5’-3’ exonuclease activity

removes primers

Question 9

DNA polymerase III

Answer 9

has proofreading

but is major for elongation of DNA by synthesis of lagging and leading strands

Question 10

Initiation

Answer 10

melting of the DNA at origins of replication
regulated step
want high ATP/ADP ratio

Question 11

Elongation

Answer 11

leading and lagging strand synthesis

Question 12

Termination

Answer 12

halting of polymerases and resolving catenated chromosomes

Question 13

Pol alpha

Answer 13

primase

initiates DNA synthesis

Question 14

Pol Beta

Answer 14

repair 3’to 5’ exonuclease activity

Question 15

pol gamma

Answer 15

replicates mitochondrial DNA

Question 16

pol delta

Answer 16

elongate Okazaki fragments of lagging strand

Question 17

RNA pol I

Answer 17

transcribes a single gene, the precursor of large ribosomal rRNAs (18S and 28S);
rRNA gene is present in 100s of tandem copies.

Question 18

RNA pol II

Answer 18

transcribes all mRNA genes (i.e. those destined to be translated into protein), microRNA precursors and most snRNA involved in splicing
Only pol II transcripts are polyadenylated

Question 19

RNA pol III

Answer 19

transcribes small genes like tRNAs, U6 snRNA, and 5S rRNA gene.

Question 20

Alpers Syndrome

Answer 20

diffuse cerebral degeneration, psychomotor retardation, intractable epilepsy, live failure

Question 21

PEO

Answer 21

chronic, progressive, bilateral & usually symmetric ocular motility deficit & ptosis (organ prolapses). Mitochondrial PEO is accompanied by myasthenia gravis

Question 22

myasthenia gravis

Answer 22

disorder of neuromuscular transmission marked by fluctuating weakness & fatigue of certain voluntary muscle, including those innervated by brainstem motor nuclei.