original exam 2022 Flashcards
what is true about Restriction enzymes?
A. Restiction enzymes are Exonucleases
B. They make double stranded cuts at certain sequences
C. found in mammals
B. They make double stranded cuts at certain sequences
(A should be endonucleases)
(C should be bakteria)
What is true about spectrophotometry?
A. Proteins absorbs UV light at 260nm
B. The sugar molecules in DNA absorb UV light at 280nm
C. The purine and pyrimidine rings of the bases absorb UV light at 260nm
c: . The purine and pyrimidine rings of the bases absorb UV light at 260nm
(A Protein = 280nm
B Sugar = 230nm)
What is true about agarose gel electrophoresis
a. DNA molecules are seperated by size
b. the DNA solution must first be treated with SDS
c. the largest fragments travel more slowly than the smallest
d. agarose denatures the DNA molecules so that they can travel in the gel
A and C
A. DNA molecules are seperated by size
C. the largest fragments travel more slowly than the smallest
(B not SDS , D not gel but PCR)
Which is false about detection of nucleic acids? (choose one option)
A.- DNA can be detected using UV light if ethidium bromide has been added to the gel
B. A circular plasmid will migrate as a band on agarose gel electrophoresis
C. Nucleic acids can be detected in cells using fluorescence in situ hybridisation
D. A DNA ladder must be included in a well to be able to estimate the size of the DNA fragments
B. A circular plasmid will migrate as a band on agarose gel electrophoresis
( A circular plasmid will migrate as SEVERAL band on agarose gel electrophoresis)
What happens in the hybridization step of a Polymerase Chain Reaction (PCR) cycle?
A. The DNA strands are separated
B.Primer binds to DNA template
C. DNA is synthesized
B.Primer binds to DNA template
(A .The DNA strands are separated = DENATURING.
C. DNA is synthesized= ELONGING)
What defines the area that is amplified in the PCR reaction?
A. Promoter
B. DNA polymerase
C. Primer
D. dNTPs
C. Primer
What is not found in a PCR tube?
A.DNA polymerase
B. Primer
C. Restriction enzymes
C. Restriction enzymes
When designing primers, it is important to;
A.have a
hybridization temperature above 55 degrees to avoid mispriming
B.have 40-60% AT
content to promote hybridization
C. avoid partial
complementarity in the primer sequences for to avoid primer dimers
A and C
(have a
hybridization temperature above 55 degrees to avoid mispriming
AND avoid partial
complementarity in the primer sequences for to avoid primer dimers
(B 40-60% GC
content to promote hybridization)
Horizontal gene transfer in prokaryotes can occur by
A. Transformation
B. Meiosis
C. Transduction
D. Transfection
A and C
(Transformation and Transduction)
(Transfection= PLASMID IN MAMALS CELL)
During Sanger sequencing, all types of ddNTP (ddATP, ddCTP, ccGTP, ddTTP) are added to a
reaction mixture together with other components and DNA template. Which statement is
correct about Sanger sequencing?
A.uses only ddNTPs,
no dNTPs are required for the sequencing reaction.
B. generates fragments that have one
ddNTP with a fluorophore attached to it.
C.The fluorophore means that the DNA polymerase is not necessary during the sequencing
- generating fragments that have one ddNTP terminal with a specific fluorophore attached to
it.
D.The bases are detected by the fluorophore emitting light of a specific wavelength.
C AND D
(C.The fluorophore means that the DNA polymerase is not necessary during the sequencing
- generating fragments that have one ddNTP terminal with a specific fluorophore attached to
it.
D.The bases are detected by the fluorophore emitting light of a specific wavelength)
What is true about reverse transcription?
A.needs the enzyme reverse transcriptase.
B. Uses RNA as a template to form cDNA.
C. DNA viruses use reverse transcription to integrate into the host cell’s genome.
D.Used to analyze genomic DNA
A and B
(A.needs the enzyme reverse transcriptase.
B. Uses RNA as a template to form cDNA)
What is false about plasmids?
A.They are small in size
B.The presence of insert cannot be detected
C. they can be grown in large quantities.
D.they are replicated independently of the bacteria’s chromosomal DNA
B.The presence of insert cannot be detected
A,C,and D CORRECT!
PLASMID= -SMALL size
- grown in LARGE quantities
-REPLICATED independently of the bacteria’s chromosomal DNA
Which enzyme is used in Polymerase Chain Reaction (PCR)? What properties are
necessary for this enzyme?
Enzyme PCR: DNA Polymerase .
Properties: stable at high
temperatures and performs DNA synthesis at 72 degrees
In which natural processes in the cell does DNA ligase have a function?
How is DNA ligase used
in DNA cloning?
DNA ligase Function: DNA repair( to glue DNA strands together after the correct bases have been
inserted).
DNA ligase used
in DNA cloning : DNA ligase( to glue vector and insert together)
What are the differences between DNA cloning and CRISPR technology?
DNA cloning: give new characteristics to an organism.
Enzyme: restriction enzymes
CRISPR : one edits one’s own genes
Enzyme: Cas9 that makes double-stranded cuts
When carrying out DNA cloning using restriction enzymes, the vector is often opened with two
enzymes. Why?
Two restriction enzymes are used so that create sticky ends not complementary to each other, therefore will not stick back to each other
SHORT ANSWER ( will be able to give
direction to the insert)
