ASCP Molecular Biology Exam Prep
UPDATED ACTUAL Questions and
CORRECT Answers
Pyrimidine - CORRECT ANSWER - one carbon ring
Cytosine, Thymine, Uracil
Purine - CORRECT ANSWER - two carbon rings
Adenine, Guanine
How are nucleotides joined together? - CORRECT ANSWER - condensation
What does mRNA do? - CORRECT ANSWER - carries code out of cell.
code for protein structure.
DNA to ribosomes
end of transcription start of translation
What does tRNA do? - CORRECT ANSWER - decodes mRNA. Matches amino acids to
mRNA code. Protein synthesis
What does rRNA do? - CORRECT ANSWER - part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback Inhibition - CORRECT ANSWER - end product of pathway is noncompetitive
inhibitor
binds to allosteric site to slow down rxn b/c too much product
,Exonucleases - CORRECT ANSWER - degrades nucleic acids by removing one terminal
nucleotide at a time
cleaves phosphodiester bond at end of chain
5' ---> 3' and 3' ---> 5'
Endonucleases - CORRECT ANSWER - cleaves phoshpodiester bonds w/in chain
recognition site is palindromic sequence
cleaves unevenly, leaves sticky ends
(restriction enzymes)
DNA polymerase III - CORRECT ANSWER - copies DNA by reading existing strand,
builds new comp. strand
always adds to 3' end
can't start new strand on its own (ORI sites)
ORI sites - CORRECT ANSWER - origin of replication on chromosome
triggers DNA replication
gyrase - CORRECT ANSWER - unwinds DNA in front of fork
DNA polymerase I - CORRECT ANSWER - removes RNA nucleotides form RNA
primers and replaces with DNA
(makes sure primers that start replication are removed)
helicase - CORRECT ANSWER - breaks H-bonds of double helix
topoisomerase - CORRECT ANSWER - breaks/ reseals DNA backbone to release tension
caused by twisting
(DNA gyrase)
, primase - CORRECT ANSWER - (RNA pol)
primers, small RNA, serves as starting points for copying DNA
helper enzyme for DNA pol III
single-strand DNA-binding proteins (SSBPs) - CORRECT ANSWER - hold DNA open
during replication
Okazaki fragments - CORRECT ANSWER - lagging strand
3' ---> 5'
away from fork
DNA pol III adds, DNA ligase closes gaps
Ligase - CORRECT ANSWER - closes gaps in DNA
forms covalent bonds b/w nucleotides, 3' end of new DNA to 5' end of growing chain
What are the steps in DNA replication? - CORRECT ANSWER - 1. Initiate
2. Elongate
3. Terminate
Telomers - CORRECT ANSWER - cap ends of chromosome during replication to preserve
DNA
-10 box - CORRECT ANSWER - TATA box (TATAAT)
located 10 bases away from transcription start site
promoter
RNA pol binding site
UPDATED ACTUAL Questions and
CORRECT Answers
Pyrimidine - CORRECT ANSWER - one carbon ring
Cytosine, Thymine, Uracil
Purine - CORRECT ANSWER - two carbon rings
Adenine, Guanine
How are nucleotides joined together? - CORRECT ANSWER - condensation
What does mRNA do? - CORRECT ANSWER - carries code out of cell.
code for protein structure.
DNA to ribosomes
end of transcription start of translation
What does tRNA do? - CORRECT ANSWER - decodes mRNA. Matches amino acids to
mRNA code. Protein synthesis
What does rRNA do? - CORRECT ANSWER - part of ribosome structure
most abundant RNA
coordinated coupling of tRNA to mRNA codons
Feedback Inhibition - CORRECT ANSWER - end product of pathway is noncompetitive
inhibitor
binds to allosteric site to slow down rxn b/c too much product
,Exonucleases - CORRECT ANSWER - degrades nucleic acids by removing one terminal
nucleotide at a time
cleaves phosphodiester bond at end of chain
5' ---> 3' and 3' ---> 5'
Endonucleases - CORRECT ANSWER - cleaves phoshpodiester bonds w/in chain
recognition site is palindromic sequence
cleaves unevenly, leaves sticky ends
(restriction enzymes)
DNA polymerase III - CORRECT ANSWER - copies DNA by reading existing strand,
builds new comp. strand
always adds to 3' end
can't start new strand on its own (ORI sites)
ORI sites - CORRECT ANSWER - origin of replication on chromosome
triggers DNA replication
gyrase - CORRECT ANSWER - unwinds DNA in front of fork
DNA polymerase I - CORRECT ANSWER - removes RNA nucleotides form RNA
primers and replaces with DNA
(makes sure primers that start replication are removed)
helicase - CORRECT ANSWER - breaks H-bonds of double helix
topoisomerase - CORRECT ANSWER - breaks/ reseals DNA backbone to release tension
caused by twisting
(DNA gyrase)
, primase - CORRECT ANSWER - (RNA pol)
primers, small RNA, serves as starting points for copying DNA
helper enzyme for DNA pol III
single-strand DNA-binding proteins (SSBPs) - CORRECT ANSWER - hold DNA open
during replication
Okazaki fragments - CORRECT ANSWER - lagging strand
3' ---> 5'
away from fork
DNA pol III adds, DNA ligase closes gaps
Ligase - CORRECT ANSWER - closes gaps in DNA
forms covalent bonds b/w nucleotides, 3' end of new DNA to 5' end of growing chain
What are the steps in DNA replication? - CORRECT ANSWER - 1. Initiate
2. Elongate
3. Terminate
Telomers - CORRECT ANSWER - cap ends of chromosome during replication to preserve
DNA
-10 box - CORRECT ANSWER - TATA box (TATAAT)
located 10 bases away from transcription start site
promoter
RNA pol binding site
