Cancer Biochemistry Exam Questions and Correct Answers Latest Update 2024 (Rated 100%)
Cancer is caused by the accumulation of genetic mutations. - Answers
Only around 5% of cancers are linked to an inherited faulty gene. - Answers
5 common environmental factors that can cause DNA mutations - Answers Drugs
UV
Obesity
Smoking
Radiation
What is MMR? - Answers DNA mismatch repair refers to the rescue system that conserves the DNA
sequences by removing the erroneous mismatched, inserted or deleted bases during the DNA
duplication and recombination. Mismatch repair system functions to maintain genomic stability and
integrity.
What is base excision repair (BER)? - Answers It is used to repair damage to bases caused by harmful
molecules by removing the base that is damaged and replacing it.
Nucleotide excision repair - Answers A repair system that removes and then correctly replaces a
damaged segment of DNA using the undamaged strand as a guide.
2 reparative mechanisms for double strand breaks - Answers HR: Homologous recombination.
NHEJ: Non-homologous end joining.
What is the purpose of MMR? - Answers To maintain DNA homeostasis.
What are microsatellites and what is microsatellite instability? - Answers Microsatellites are a sequence
of repetitive nucleotides typically occurring 5-50 times and can be seen in various locations of an
organism's genome.
Microsatellite instability (MSI) is a condition of genetic hypermutability that results from impaired DNA
mismatch repair (MMR). Microsatellites are regions of repeated DNA that change in length when MMR
is not working properly. The presence of MSI represents phenotypic evidence that MMR is not
functioning normally.
What are BRACA 1 and BRACA 2 and why are they called tumor suppressor genes? - Answers They stand
for Breast cancer genes. They are called tumor suppressor genes because they play a role in regulating
and halting cell growth and division.
, A fault (or mutation) in the BRCA1 or BRCA2 gene means that the cells can grow out of control. This can
lead to cancer developing.
Faulty BRCA1 and BRCA2 genes are rare. Only around 1 in every 400 people have a faulty BRCA1 or
BRCA2 gene. - Answers
It is important to remember that breast cancer is not the only type of cancer that can manifest due to
mutations in BRACA genes. What are some other possible cancers that can arise in both men and
women? - Answers Ovarian, prostate, and pancreatic cancers.
What is Lynch syndrome?
Up to 70 in every 100 people (70%) with Lynch syndrome will develop bowel cancer. Most people will
develop bowel cancer before the age of 50. - Answers Hereditary non-polyposis colorectal cancer .
Autosomal dominant condition. Bowel polyps are small growths on the lining of the large intestine
(colon) or rectum. They're very common and not usually serious, but sometimes they can lead to bowel
cancer.
Autosomal dominant changes in ONE of which of the following genes can cause Lynch syndrome? -
Answers MLH1, MSH2, MSH3, MSH6 or PMS2
What can microsatellite instability cause? - Answers Strand slippage- It involves denaturation and
displacement of the DNA strands, resulting in mispairing of the complementary bases.
Around 70% and 45% of women with a BRCA1/BRCA2 mutated gene will develop breast cancer or
ovarian cancer by the age of 80 - Answers
A few things that BRACA genes do: - Answers 1- Cell cycle checkpoint activation
2- Transcriptional regulation
3- Apoptosis
4- DNA double strand break repair
What 8 genes have a strong association with increased risk of breast cancer? - Answers BRCA1, BRCA2,
PALB2, BARD1, RAD51C, RAD51D, ATM and CHEK2.
We have seen previously that there are 2 main pathways for double strand break repair which are HRR
( homologous recombination repair ) and NHEJ ( Non-homologous end joining ). Explain both of them: -
Answers HRR: The complementary strand is used as a template to removed the damaged part of the
other strand, and reattach appropriate base pairs to match the complementary strand. THIS METHOD IS
ERROR FREE.
Cancer is caused by the accumulation of genetic mutations. - Answers
Only around 5% of cancers are linked to an inherited faulty gene. - Answers
5 common environmental factors that can cause DNA mutations - Answers Drugs
UV
Obesity
Smoking
Radiation
What is MMR? - Answers DNA mismatch repair refers to the rescue system that conserves the DNA
sequences by removing the erroneous mismatched, inserted or deleted bases during the DNA
duplication and recombination. Mismatch repair system functions to maintain genomic stability and
integrity.
What is base excision repair (BER)? - Answers It is used to repair damage to bases caused by harmful
molecules by removing the base that is damaged and replacing it.
Nucleotide excision repair - Answers A repair system that removes and then correctly replaces a
damaged segment of DNA using the undamaged strand as a guide.
2 reparative mechanisms for double strand breaks - Answers HR: Homologous recombination.
NHEJ: Non-homologous end joining.
What is the purpose of MMR? - Answers To maintain DNA homeostasis.
What are microsatellites and what is microsatellite instability? - Answers Microsatellites are a sequence
of repetitive nucleotides typically occurring 5-50 times and can be seen in various locations of an
organism's genome.
Microsatellite instability (MSI) is a condition of genetic hypermutability that results from impaired DNA
mismatch repair (MMR). Microsatellites are regions of repeated DNA that change in length when MMR
is not working properly. The presence of MSI represents phenotypic evidence that MMR is not
functioning normally.
What are BRACA 1 and BRACA 2 and why are they called tumor suppressor genes? - Answers They stand
for Breast cancer genes. They are called tumor suppressor genes because they play a role in regulating
and halting cell growth and division.
, A fault (or mutation) in the BRCA1 or BRCA2 gene means that the cells can grow out of control. This can
lead to cancer developing.
Faulty BRCA1 and BRCA2 genes are rare. Only around 1 in every 400 people have a faulty BRCA1 or
BRCA2 gene. - Answers
It is important to remember that breast cancer is not the only type of cancer that can manifest due to
mutations in BRACA genes. What are some other possible cancers that can arise in both men and
women? - Answers Ovarian, prostate, and pancreatic cancers.
What is Lynch syndrome?
Up to 70 in every 100 people (70%) with Lynch syndrome will develop bowel cancer. Most people will
develop bowel cancer before the age of 50. - Answers Hereditary non-polyposis colorectal cancer .
Autosomal dominant condition. Bowel polyps are small growths on the lining of the large intestine
(colon) or rectum. They're very common and not usually serious, but sometimes they can lead to bowel
cancer.
Autosomal dominant changes in ONE of which of the following genes can cause Lynch syndrome? -
Answers MLH1, MSH2, MSH3, MSH6 or PMS2
What can microsatellite instability cause? - Answers Strand slippage- It involves denaturation and
displacement of the DNA strands, resulting in mispairing of the complementary bases.
Around 70% and 45% of women with a BRCA1/BRCA2 mutated gene will develop breast cancer or
ovarian cancer by the age of 80 - Answers
A few things that BRACA genes do: - Answers 1- Cell cycle checkpoint activation
2- Transcriptional regulation
3- Apoptosis
4- DNA double strand break repair
What 8 genes have a strong association with increased risk of breast cancer? - Answers BRCA1, BRCA2,
PALB2, BARD1, RAD51C, RAD51D, ATM and CHEK2.
We have seen previously that there are 2 main pathways for double strand break repair which are HRR
( homologous recombination repair ) and NHEJ ( Non-homologous end joining ). Explain both of them: -
Answers HRR: The complementary strand is used as a template to removed the damaged part of the
other strand, and reattach appropriate base pairs to match the complementary strand. THIS METHOD IS
ERROR FREE.
