Final - DNA, protein Flashcards
What property allows the dideoxynucleoside triphosphates (ddNTPs) to terminate DNA synthesis when added to a growing chain?
ddNTPs have a -H group instead of a -OH group at the 3’ position of the ribose.
How was the molecular weight of the protein subunits determined in the SDS-PAGE lab?
Choose one answer.
a. Through comparing the brightnesses of bands.
b. Through constructing a standard curve.
c. Liquid chromatography.
d. Sucrose gradient.
e. Size exclusion chromatography
b. Through constructing a standard curve.
In lab, polypeptides were separated on a \_\_\_\_\_\_\_\_\_\_\_\_\_ while DNA fragments were separated on a \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. Choose one answer. a. agarose gel; polyacrylamide gel b. vertical gel; horizontal gel c. polyacrylamide gel; agarose gel d. SDS-PAGE; vertical gel
c. polyacrylamide gel; agarose gel
After running an electrophoresis experiment, various methods are used to visualize the electrophoresed molecules. In the SDS-PAGE lab, what method of visualization was used to allow us to see the protein bands?
Choose one answer.
a. UV illumination alone since the proteins were already pre-labeled with FITC, a covalently attached florescent tag.
b. Florescent-tagged antibodies specific from each of the proteins were added to the gel to enable visualization
c. Immersion of the gel in Coomassie blue, an intense stain which binds the proteins
d. Ethidium Bromide staining followed by illumination with UV light
e. No visualization method was necessary since the bands could be seen with the unaided eye
a. UV illumination alone since the proteins were already pre-labeled with FITC, a covalently attached florescent tag.
Which one of the rules is not correct for the primer design? Choose one answer.
a. Guanine and cytocine (G and C) should make up 50-60% of total base.
b. Primers should end (5’) in a G or C, or CG or GC
c. The melting temparature should be between 55-80
d. Four or more of the same base in a row can result in mispriming.
e. Primers should be between 20-30 base pair long.
b. Primers should end (5’) in a G or C, or CG or GC
After performing a gel electrophoresis with sample proteins that have multiple subunits, John noticed that all his protein samples moved down the gel but there was only one band in each of his gel lanes when there was supposed to be more than one. He was confused because he even added denaturing detergent to his samples. What could have been a mistake John made?
a. John accidently reversed the red and black wires on this electrophoresis apparatus.
b. The proteins were resistant to the electric field running down the polyacrylamide gel.
c. John’s gel rig did not contain the right buffer solution so that could have damaged the polyacrylamide gel.
d. John forgot to heat his protein samples to denature them.
e. The voltage on the power supply of John’s electrophoresis apparatus was too weak.
d. John forgot to heat his protein samples to denature them.
Which of these primer design problems is the most serious for the PCR procedure?
Select one:
a. The sequence has mismatched nucleotides in the center because shifted sequences will amplify mutation affecting protein function.
b. The sequence has mismatched nucleotides at the 5’ end because PCR cannot begin correctly from this mismatch.
c. The sequence has mismatched nucleotides at the 3’ end because the replication cannot extend from this mismatch.
d. The sequence is greater than 20 base pairs long.
e. The sequence has an altered melting temperature due to a deficiency of A-T bonds.
c. The sequence has mismatched nucleotides at the 3’ end because the replication cannot extend from this mismatch.
A scientist runs an SDS-PAGE experiment two separate times on a protein with a molecular weight of 200 kD. For the first experiment he treats the protein with SDS only and for the second experiment he treats the protein with both SDS and a reducing agent. If the first gel yields one band showing a molecular weight of 200 kD and the second run yields one band showing a molecular weight of 25 kD, the researcher should conclude that
Select one:
a. The protein contains only covalent bonds and no non-covalent interactions.
b. The protein contains no disulfide linkages.
c. The consists of 8 subunits of equal size connected by a disulfide linkage.
d. The protein has only 1 subunit because both runs yield a single band.
e. The consists of 2 subunits of equal size connected by a disulfide linkage.
c. The consists of 8 subunits of equal size connected by a disulfide linkage.
All of the following characterize a good PCR primer except:
Select one:
a. high Guanine and Cytosine content
b. 100-110 base pair length
c. lack of consecutive identical base pairs
d. similar melting points for forward and reverse primers
b. 100-110 base pair length
An antibody, with molecular weight 90 kD in its native state, is treated with SDS and a reducing agent before being loaded onto an SDS-PAGE gel. The result shows 2 bands, one is 20 kD and the other band is at 50 kD. How many subunits are in this antibody?
Select one:
a. 1
b. 2
c. 3
d. 4
e. 5
c. 3`
In the Gel Electrophoresis lab, why did we not add SDS and beta mercaptoethanol to the agarose gel before loading our PCR product?
a. The agarose gel is non-toxic, so we do not need SDS and beta mercaptoethanol.
b. The PCR product is so small that SDS and beta mercaptoethanol are not needed.
c. The agarose gel was run horizontally instead of vertically.
d. The GelRed acted as a reducing agent and gave the PCR product a negative charge.
e. The PCR product is already linear and has a negative charge associated with it.
e. The PCR product is already linear and has a negative charge associated with it.
The Sanger method does NOT use which of the following:
Select one:
a. dNTPs as the building block of the newly synthesized strands
b. DNA polymerase to catalyze the reaction
c. a sequencing primer for annealing to the template
d. ddNTPs as the terminator of the newly synthesized strands
e. RNA as the template to be sequenced
e. RNA as the template to be sequenced
All of the following is true about agarose gels EXCEPT:
Select one:
a. Agarose gel electrophoresis can be used for the separation of DNA fragments.
b. Agarose gel electrophoresis has a higher resolution than SDS-PAGE.
c. Conventionally, agarose gel electrophoresis is set up horizontally.
d. The pores in agarose gels are bigger than those in polyacrylamide gels.
e. Agarose is safe to handle, whereas acrylamide is a neurotoxin.
b. Agarose gel electrophoresis has a higher resolution than SDS-PAGE.
