Molecular Biology Questions

Genes in eukaryotic cells often have intronic sequences coded for within the DNA. These sequences are ultimately Not translated into proteins because ?(a) Intronic sequences are removed from RNA molecules by the spliceosome, which works in the nucleus(b) introns are not transcribed by RNA polymerase(c) Introns are removed by catalytic RNAs in the cytoplasm(d) The ribosome will skip over intron sequences when translating RNA into protein

Which of the following statements about differentiated cells is true?(a) cells of distinct types express non-overlapping sets of transcription regulators(b) once a cell has differentiated, it can no longer change its gene expression(c) once a cell has differentiated, it will no longer need to transcribe RNA(d)some of the proteins found in differentiated cells are found in all cells of a multicellular organism

Which of the following statements about transcriptional regulators is FALSE?(a) transcriptional regulators usually interact only with the sugar-phosphate backbone on the outside of the double helix to determine where to bind on the DNA helix(b) transcriptional regulators will form hydrogen bonds, ionic bonds, and hydrophobic interactions with DNA(c) the DNA-binding motifs of transcriptional regulators usually bind in the major groove of the DNA helix (d) the binding of the transcriptional regulators generally does not disrupt the hydrogen bonds that hold the double helix together

which of the following functions are NOT attributed to ribozymes:(a) peptide bond formation(b) RNA splicing (c) DNA ligation (d) DNA acetylation

Which of the following does NOT occur before a eukaryotic mRNA is exported from the nucleus? (a) the ribosomes bind to the mRNA(b) the mRNA is polyadenylated at its 3' end(c) 7-methylguanosine is added in a 5'-to-5' linkage to the mRNA(d)) RNA polymerase dissoiates

Which of the following statements about RNA splicing is FALSE?(a) conventional introns are not found in bacterial genes(b) for an mRNA to function properly, every exon must be removed and discarded from the primary transcript in the same fashion on every transcript produced from the same gene.(c) small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns(d) splicing occurs after the 5' cap has been added to the end of the primary transcript

Which statement is CORRECT for transcription and DNA replication?(a)they use different polymerases(b) both need RNA primers(c) the newly synthesized RNA remains paired to the template DNA(d) nucleotide polymerization occurs in both 5'-to-3' and 3'-to-5' direction

According to current thinking, what molecules are considered as the origin of life on earth?

Sickle-cell anemia is an example of an inherited disease. Individuals with this disorder have misshapen (sickle-shaped) red blood cells caused by a change in the sequence of the beta-globin gene. What is the nature of the change? (a) chromosome loss(b) Substitution mutation (base-pair change)(c) gene duplication(d) insertion mutation (base-pair insertion)

Which of the following statements is NOT an accurate statement about thymine dimers (a) thymine dimers can cause the DNA replication machinery to stall(b) thymine dimers are covalent links between thymidine's on opposite DNA strands(c) prolonged exposure to sunlight causes thymine dimers to form(d) repair proteins recognize thymine dimers as a distortion in the DNA backbone

Which of the following statements correctly explains what it means for DNA replication to be Bidirectional?

Sometimes, chemical damage to DNA can occur just before DNA replication begins, not giving the repair system enough time to correct the error before the DNA is duplicated. This gives rise to mutation. If the CYTOSINE in the sequence TCAT is deaminated to Uracil and NOT repaired, which of the following is the point mutation you would observe after this segment has undergone TWO rounds of DNA replication?(a) TTAT(b) TUAT(c) TGAT(d) TAAT

Which statement is INNCORRECT?(a) Ozaki fragments are joined by DNA ligase(b) the newly synthesize chromosome DNA copy is shorter than the original template due to the loss of telomere repeats during replication(c) the replication origin is a specialized sequence where initiator proteins bind and open the DNA so that the DNA replication machinery can assemble. (d) A primer is only required for the initiation of lagging strand but not leading strand

During chromosome duplication, primase synthesizes primers to initiate OKAZAKI fragments--which one is UNLIKELY a primer produced by primase:(a) AAAGGAA(b) GAGCGCA(c) AAAUGGC(d) GTAGCAG

Free-energy change of two reacting molecules at standard temperature and pressure when all components are present at a concentration of 1 mol per liter is called ____?

The effective ionic interactions in proteins are _____ due to interactions with water.

The viral protein that mediates SARS-CoV-2 entry of host cells is:

The photo 51 was historically the most important X-ray diffraction image of DNA which was generated by Dr. Rosalind Franklin and her graduate student Raymond Gosling in May 1952. Which atom in DNA was visible in that picture?

Which of the following statements about sequence proofreading during DNA replication by DNA polymerase III is FALSE(a) The exonuclease activity is in a different domain of the DNA polymerase(b) The exonuclease activity cleaves DNA in the 5'-to-3' direction(c) The DNA proofreading activity occurs concomitantly with strand elongation(d) If an incorrect base is added, it is "unpaired" before removal

what part of the DNA replication process would be directly and immediately affected if a strain of bacteria lacking primase were used to make the cell extracts? (a) Initiation of DNA sysnthesis(b) Okazaki fragment synthesis(c) leading-strand elongation(d) lagging-strand completion