Question 1

What post-translational modification will cause the biggestincrease in the size of a protein, immediately when added?

Select one:

a. Phosphorylation

b. Ubiquitination

c. Acetylation

d. Methylation

Question 2

What does HMT do?

Select one:

a. It acts as an epigenator

b. It modifies nitrogenous bases

c. It produces euchromatin

d. It modifies histones

Question 3

Where can an epigenetic maintainer act?

Select one:

a. On the sequence of nucleotides

b. On the sequence of nucleotides and on the nucleotidesdirectly

c. On certain nucleotides and amino acids

d. On certain amino acids

e. On certain nucleotides

Question 4

Which of the following types of protein could be coded by atumour-suppressor gene?

Select one:

a. A protein that stimulate progression through the cellcycle.

b. A protein that forms part of a growth factor signalingpathway.

c. A protein that codes for a DNA repair enzyme.

d. A protein that helps prevent apoptosis.

e. A protein that repairs lost telomeres

Question 5

Which is NOT a typical mechanism by which a proto-oncogene isconverted to an oncogene?

Select one:

a. A point mutation in the proto-oncogene

b. A chromosomal translocation resulting in the up-regulation ofthe proto-oncogene

c. Duplication of a chromosome region containing aproto-oncogene

d. Complete deletion of the proto-oncogene

e. Amplification of the proto-oncogene

Question 6

Why do you think familial retinoblastoma and Li-Fraumeni areconsidered to be inherited as autosomal dominant traits when theresponsible genes are recessive?

Select one:

a. They are expressed in a dominant fashion in males, butrecessive in females.       

b. People with this mutation are always homozygous for thisallele.

c. If you are born with one allele mutated in every cell, thechance that the other allele will be mutated in one of the retinalcells is extremely high.

d. This recessive gene needs only one copy to express thisphenotype.

e. Retinoblastoma was mischaracterized originally when it wascalled an autosomal dominant trait.

Question 7

Question text

In a normal cell, pRB binds to __________, which inhibits celldivision. In the presence of __________ pRB becomes __________,which leads to cell division.

Select one:

a. cyclin+Cdk; oncogenes; dephosphorylated

b. transcription factors; cyclin+Cdk; phosphorylated

c. tumor suppressor; p53; phosphorylated

d. p21; p53; dephosphorylated

e. tumor suppressor; p21; hyperactive

Question 8

The following information relates to the next threequestions:

A few decades ago, Knudsen and colleagues proposed a theorythat, for a normal cell to become a cancer cell, a minimum of twogenetic changes had to occur in that cell. Knudsen was studyingretinoblastoma, a childhood cancer of the eye.

Two children are born from the same parents. Child one inheritsa predisposition to retinoblastoma (one of the mutations) and childtwo does not. However, both children develop the retinoblastoma.Which of the following would you expect?

Select one:

a. a history of exposure to mutagens in child one but not inchild two

b. increased levels of apoptosis in both children

c. an earlier age of onset in child one

d. decreased levels of DNA repair in child one

e. a more severe cancer in child one

Question 9

In colorectal cancer, several genes must be mutated in order tomake a cell a cancer cell, supporting Knudsen’s hypothesis. Whichof the following kinds of genes would you expect to be mutated?

Select one:

a. genes that are especially susceptible to mutation

b. the same genes that Knudsen identified as associated withretinoblastoma

c. genes coding for enzymes that act in the colon

d. the genes of the bacteria that are abundant in the colon

e. genes encoding transcription factors that regulate cyclinproduction

Question 10

Knudsen and colleagues also noted that persons with hereditaryretinoblastoma that had been treated successfully lived on but thenhad a higher frequency of developing osteosarcomas (bone cancers)later in life. This provided further evidence of their theorybecause:

Select one:

a. osteosarcoma cells express the same genes as retinalcells.

b. one of the mutations involved in retinoblastoma is also oneof the changes involved in osteosarcoma.

c. p53 gene mutations are common to both tumours.

d. retinoblastoma is a prerequisite for the formation ofosteosarcoma later in life.

e. both kinds of cancer involve uncontrolled proliferation ofcells.