Ch. 19 Quiz Flashcards
What causes cancer?
Somatic mutations that disrupt normal cell division and death
Mark the correct statement: A carcinogen is always a mutagen because it will always react with DNA.
A carcinogen never reacts with DNA, but instead alters protein folding.
Which protein regulates the cell cycle by monitoring the environment of each stage and making sure the previous cycle is complete?
Cyclins
What activates cell division?
Growth factors
Which of the following statements about oncogenes and anti-oncogenes is not true?
Mutations in oncogenes are recessive and can often be overcome by the non-affected, Wild-type allele
How do oncogenic viruses form?
Upon excision from the genome, the virus “picks up” an oncogene from the host.
How might oncogenes be detected?
Transformation of suspect DNA into animal cells and observations of cell growth (i.e. lack of contact inhibition)
Which of the following causes a proto-oncogene to become an oncogene?
All of the above
- A mutation within the regulatory region of the proto-oncogene that increases expression of that gene
- A mutation in the coding region that changes the amino acid sequence to make the protein hyperactive.
- A genetic rearrangement of the proto-oncogene that places the gene behind a strong promoter, thus increasing expression
- A duplication in the proto-oncogene
How does Ras become an oncogene?
By a mutation in the genetic code that alters one of three amino acid residues involved in the binding and splitting of GTP
A mutation in which oncogene tends to occur in the later progression of lung, breast, and ovarian cancers?
Myc
What is nullizygous?
When both copies of an anti-oncogene have been inactivated by mutations
Why does a mutation in only one p53 anti-oncogene allele cause a defect in the tetrameric protein?
Because p53 is expressed from both alleles and one mutant copy causes half of the tetramer to be defective
Which of the following is a mutation associated with colon cancer?
All of the above
- Inactivation of both copies of the APC anti-oncogene
- Activation of the Ras oncogene
- Mutation in one copy of the p53 gene
- Inactivation of both copies of the DCC anti-oncogene
Which of the following inherited defects predisposes a person to cancer?
All of the above
- DNA repair systems
- Anti-oncogenes
- Components of DNA replication
- Genetic differences between races
How is a virus made oncolytic?
Changing the viral protein that binds to the host cells so that it only recognizes and infects, then kills, cancer cells
