TLS Online TPP Program

#Question id: 2901


HOTAIR is a lncRNA whose gene is found in the HoxC cluster in humans, but it acts by regulating expression of the HoxD genes on another chromosome (in trans) by recruiting to that locus Polycomb Repressive Complex 2 (PCR2). Which of the following processes is incorrect regarding this regulation?

#Unit 2. Cellular Organization
  1. PRC2 adds trimethyl groups to lysine 9 of histone H3, a mark (H3K9me3) associated with repressed gene expression.

  2. HOTAIR also recruits a second complex that removes histone modifications typically associated with active genes.

  3. HOTAIR has also been found to be up-regulated in some cancers. Deleting the PRC2-binding domain of HOTAIR destroys its regulatory functions in both development and cancer.

  4. HOTAIR never found to be up-regulated in some cancers. Deleting the PRC2-binding domain of HOTAIR destroys its regulatory functions in both development and cancer.

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TLS Online TPP Program

#Question id: 3823

#Unit 3. Fundamental Processes

Regarding DNA replication and DNA synthesis, which, if any, of the following statements is incorrect?

TLS Online TPP Program

#Question id: 3824

#Unit 3. Fundamental Processes

State whether the following statements is true/false regarding DNA replication.

1. The polymerization of DNA is essentially irreversible due to the hydrolysis of pyrophosphate.

2. On average about twenty errors are made during each replication of the human genome.

3. DNA polymerase I possesses 5ʹ → 3ʹ exonuclease activity.

4. All DNA ligase enzymes use ATP as a cosubstrate.

5. The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions.

TLS Online TPP Program

#Question id: 3825

#Unit 3. Fundamental Processes

Telomeres are the repetitive sequence of T's and G's that are present in the eukaryotes to protect the random cleavage from nucleases. These telomeres are synthesized by the enzyme telomerase. Which of the following are the properties of enzyme telomerase?

TLS Online TPP Program

#Question id: 3826

#Unit 3. Fundamental Processes

Which scientists first gave experimental evidence that DNA is the genetic material?

TLS Online TPP Program

#Question id: 3827

#Unit 3. Fundamental Processes

It takes about the same amount of time for eukaryotic chromosomes to be replicated in vivo as it does for E. coli. Why is this true?

TLS Online TPP Program

#Question id: 3828

#Unit 3. Fundamental Processes

Why does E. coli need both DNA polymerase III and DNA polymerase I?