ASCP Molecular Biology Exam
Prep Questions and Answers
100% PASS
Pyrimidine—ANSWER-one carbon ring
Cytosine, Thymine, Uracil
Purine—ANSWER-two carbon rings
Adenine, Guanine
How are nucleotides joined together?—ANSWER-condensation
What does mRNA do?—ANSWER-carries code out of cell.
code for protein structure.
DNA to ribosomes
end of transcription start of translation
What does tRNA do?—ANSWER-decodes mRNA. Matches amino acids to mRNA code.
Protein synthesis
What does rRNA do?—ANSWER-part of ribosome structure
most abundant RNA
,coordinated coupling of tRNA to mRNA codons
Feedback Inhibition—ANSWER-end product of pathway is noncompetitive inhibitor
binds to allosteric site to slow down rxn b/c too much product
Exonucleases—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—ANSWER-cleaves phoshpodiester bonds w/in chain
recognition site is palindromic sequence
cleaves unevenly, leaves sticky ends
(restriction enzymes)
DNA polymerase III—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—ANSWER-origin of replication on chromosome
triggers DNA replication
gyrase—ANSWER-unwinds DNA in front of fork
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Brittie Donald
, DNA polymerase I—ANSWER-removes RNA nucleotides form RNA primers and replaces with
DNA
(makes sure primers that start replication are removed)
helicase—ANSWER-breaks H-bonds of double helix
topoisomerase—ANSWER-breaks/ reseals DNA backbone to release tension caused by
twisting
(DNA gyrase)
primase—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)—ANSWER-hold DNA open during replication
Okazaki fragments—ANSWER-lagging strand
3' ---> 5'
away from fork
DNA pol III adds, DNA ligase closes gaps
Ligase—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?—ANSWER-1. Initiate
2. Elongate
Prep Questions and Answers
100% PASS
Pyrimidine—ANSWER-one carbon ring
Cytosine, Thymine, Uracil
Purine—ANSWER-two carbon rings
Adenine, Guanine
How are nucleotides joined together?—ANSWER-condensation
What does mRNA do?—ANSWER-carries code out of cell.
code for protein structure.
DNA to ribosomes
end of transcription start of translation
What does tRNA do?—ANSWER-decodes mRNA. Matches amino acids to mRNA code.
Protein synthesis
What does rRNA do?—ANSWER-part of ribosome structure
most abundant RNA
,coordinated coupling of tRNA to mRNA codons
Feedback Inhibition—ANSWER-end product of pathway is noncompetitive inhibitor
binds to allosteric site to slow down rxn b/c too much product
Exonucleases—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—ANSWER-cleaves phoshpodiester bonds w/in chain
recognition site is palindromic sequence
cleaves unevenly, leaves sticky ends
(restriction enzymes)
DNA polymerase III—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—ANSWER-origin of replication on chromosome
triggers DNA replication
gyrase—ANSWER-unwinds DNA in front of fork
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Brittie Donald
, DNA polymerase I—ANSWER-removes RNA nucleotides form RNA primers and replaces with
DNA
(makes sure primers that start replication are removed)
helicase—ANSWER-breaks H-bonds of double helix
topoisomerase—ANSWER-breaks/ reseals DNA backbone to release tension caused by
twisting
(DNA gyrase)
primase—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)—ANSWER-hold DNA open during replication
Okazaki fragments—ANSWER-lagging strand
3' ---> 5'
away from fork
DNA pol III adds, DNA ligase closes gaps
Ligase—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?—ANSWER-1. Initiate
2. Elongate
