GENETICS EXAM 3 COMPREHENSIVE STUDY
QUESTIONS AND ANSWERS
◉ UV light radiation on a sunny day may cause 50,000 thymine
dimers in the DNA of fibroblasts in on individual during one day.
With such a high amount of DNA damage, why damage, why don't
more people end up with skin cancer?
Answer: Thymine dimers get repaired by special DNA repair
enzymes
◉ Genomic imprinting------------.
Answer: is an epigenetic modification which changes from
generation to generation
◉ True/false. Because of genetic imprinting, only the maternal copy
of two homologous chromosomes gets expressed
Answer: False
◉ Tumor suppressor genes are often
Answer: mutated in cancer cells
◉ Cancer cells
Answer: A. may lack appropriate DNA repair mechanisms
, B. grow uncontrollably
C. may migrate to other tissues
D. can override cell cycle control mechanism
E. all of the above
◉ Oncogenes (Proto-oncogenes) are often
Answer: activated in cancer cells
◉ Tumor suppressor genes
Answer: Example: p53 RB (Retinoblastoma)
◉ Oncogenes
Answer: Example: ras
◉ True or false
Cancer can occur when a DNA repair gene gets mutated
Answer: true
◉ In the progression of colon cancer
Answer: several mutations involving various tumor suppressor
genes and oncogenes occur
QUESTIONS AND ANSWERS
◉ UV light radiation on a sunny day may cause 50,000 thymine
dimers in the DNA of fibroblasts in on individual during one day.
With such a high amount of DNA damage, why damage, why don't
more people end up with skin cancer?
Answer: Thymine dimers get repaired by special DNA repair
enzymes
◉ Genomic imprinting------------.
Answer: is an epigenetic modification which changes from
generation to generation
◉ True/false. Because of genetic imprinting, only the maternal copy
of two homologous chromosomes gets expressed
Answer: False
◉ Tumor suppressor genes are often
Answer: mutated in cancer cells
◉ Cancer cells
Answer: A. may lack appropriate DNA repair mechanisms
, B. grow uncontrollably
C. may migrate to other tissues
D. can override cell cycle control mechanism
E. all of the above
◉ Oncogenes (Proto-oncogenes) are often
Answer: activated in cancer cells
◉ Tumor suppressor genes
Answer: Example: p53 RB (Retinoblastoma)
◉ Oncogenes
Answer: Example: ras
◉ True or false
Cancer can occur when a DNA repair gene gets mutated
Answer: true
◉ In the progression of colon cancer
Answer: several mutations involving various tumor suppressor
genes and oncogenes occur
