Practice Questions

TLS Online TPP Program

#Question id: 2882

SUMO (small ubiquitin-related modifier) proteins are ∼10-kD polypeptides that function as reversible post-translational protein modifiers. They form isopeptide bonds with ɛ-amino groups of acceptor Lys residues in hundreds of target proteins in a process termed as sumoylation. Which of the following statements is correct regarding this modification?

#Unit 2. Cellular Organization

A short non-covalent SUMO-interaction/binding motif (SIM/SBM) has been identified in all SUMO enzymes, targets and downstream effectors. This motif contributes to the mechanism and consequences of sumoylation.
Acceptor Lys residues in target proteins are frequently found in the consensus motif ΨKxD although the number of targets with non-consensus acceptor sites is steadily increasing.
Irreversible sumoylation contributes to many distinct pathways, such as chromatin structure, DNA repair, transcription, cell-cycle progression and trafficking.
Sumoylation alters the molecular interactions of modified target proteins by masking or adding interaction surfaces. Downstream consequences, which are target dependent, include changes in localization, activity and protein stability.

More Questions

#Question id: 2809

#Unit 2. Cellular Organization

In the human genome, one centimorgan or a 1 percent recombination frequency represents, on average, a distance of about

#Question id: 2810

#Unit 2. Cellular Organization

Which of the following steps is required to generate a knockout mouse?

a. microinjection of DNA into the pronucleus of a fertilized mouse egg

b. introduction of DNA into mouse embryonic stem cells

c. selection for cells containing the gene targeted insertion

d. expression of Cre protein during embryonic development

#Question id: 2811

#Unit 2. Cellular Organization

RNA interference is a method for inhibiting the function of specific genes using

a. single-stranded DNA.

b. double-stranded DNA.

c. single-stranded RNA.

d. double-stranded RNA.

#Question id: 2812

#Unit 2. Cellular Organization

Which of the following statements is (are) true of the human genome?

a. 1.5 percent of the genome corresponds to protein coding sequences.

b. The median length of an intron is 10 kb.

c. 10 percent of the genome is transcribed into pre mRNA precursors.

d. Most human exons contain 500–1000 base pairs.

#Question id: 2813

#Unit 2. Cellular Organization

DNA fingerprinting is a technique based on differences in the

a. length of introns.

b. number of tandem copies of a simple sequence repeat.

c. number of tandem ribosomal RNA genes.

d. size of protein coding genes.

#Question id: 2814

#Unit 2. Cellular Organization

LINES (long interspersed elements)