MCDB EXAM 2 QUESTIONS AND
ANSWERS
What are DNA mutations ? - Correct Answers --point mutation
-indel(small insertion or deletion)
-large mutations (amplification or translocation)
What is a point mutation ? - Correct Answers -A point mutation is Change in a single
base pair
-can be caused by a replication error
-can be also caused by a mutagen
What is a transition? - Correct Answers --10x more frequent than transversions
-the base stays the same (PYR to PYR)
What is a transversion? - Correct Answers --purine to pyrimidine or pyrimidine to purine
- less likely to occur because it's hard to mutate shit with a purine (bigger)
What is a mutagen? - Correct Answers -anything that causes a mutation
What is a silent mutation? - Correct Answers -Amino acid remains unchanged due to
degenerate genetic coding (multiple codons code for same AA)
What is a nonsense mutation? - Correct Answers -a stop codon is prematurely
encountered, leads to an smaller protein.
What is a missense mutation? - Correct Answers -Point mutation in which a single
nucleotide is changed, resulting in a codon that codes for a different amino acid.
What is a conservative vs. nonconservative mutation - Correct Answers -A conservative
missense still has the same function and shape whereas a non-conservative is a
completely different type of Amino Acid
What is a frameshift mutation ? - Correct Answers -Insertion or deletion that is not in a
multiple of 3, changes reading frame
What are indels? - Correct Answers -An indel is an insertion or deletion
What causes indels - Correct Answers --replication slippage
, -repair of a dna double strand break
What happens if the newly synthesized strand creates a small loop? - Correct Answers -
An insertion will occur
What happens if the template strand forms a loop? - Correct Answers -A deletion
occurs, (one nucleotide is left out)
What is the most likely result of a frameshift mutation? - Correct Answers -Early stop
codon, shorter/non functional protein
What happens if a deletion/insertion with a multiple of 3 occurs ? - Correct Answers -
protein will have one extra AA or one less, situational mutation that depends on the
structure and effect
what are Large Scale mutations? - Correct Answers --caused by aberrant recombination
events (repair of DNA double strand breaks)
-or large insertions of other chromosomes
-translocations
What are consequences of a large scale insertions and translocations? - Correct
Answers --imbalance in gene expression
-expression of oncogenes
What is an oncogene? - Correct Answers -blocks cell regulation, replication always
active (brick left on the gas)
What is a BCR/ABL translocation? - Correct Answers --lose part of ABL gene (ABL AND
BCR on same chromosome)
-loss of cell cycle control
-leukemia results
What is Burkitt's translocation? - Correct Answers --Myc (oncogene) fused to active
promoter
-High Myc expression
-Lymphoma
What types of Damage is DNA constantly exposed to ? - Correct Answers --reactive
chemical species that are results of normal metabolic processes
-environmental factors
-breaks created on purpose
How many times are lesions(damage) repaired in the cell? - Correct Answers -10^4 to
10^6 times per day
ANSWERS
What are DNA mutations ? - Correct Answers --point mutation
-indel(small insertion or deletion)
-large mutations (amplification or translocation)
What is a point mutation ? - Correct Answers -A point mutation is Change in a single
base pair
-can be caused by a replication error
-can be also caused by a mutagen
What is a transition? - Correct Answers --10x more frequent than transversions
-the base stays the same (PYR to PYR)
What is a transversion? - Correct Answers --purine to pyrimidine or pyrimidine to purine
- less likely to occur because it's hard to mutate shit with a purine (bigger)
What is a mutagen? - Correct Answers -anything that causes a mutation
What is a silent mutation? - Correct Answers -Amino acid remains unchanged due to
degenerate genetic coding (multiple codons code for same AA)
What is a nonsense mutation? - Correct Answers -a stop codon is prematurely
encountered, leads to an smaller protein.
What is a missense mutation? - Correct Answers -Point mutation in which a single
nucleotide is changed, resulting in a codon that codes for a different amino acid.
What is a conservative vs. nonconservative mutation - Correct Answers -A conservative
missense still has the same function and shape whereas a non-conservative is a
completely different type of Amino Acid
What is a frameshift mutation ? - Correct Answers -Insertion or deletion that is not in a
multiple of 3, changes reading frame
What are indels? - Correct Answers -An indel is an insertion or deletion
What causes indels - Correct Answers --replication slippage
, -repair of a dna double strand break
What happens if the newly synthesized strand creates a small loop? - Correct Answers -
An insertion will occur
What happens if the template strand forms a loop? - Correct Answers -A deletion
occurs, (one nucleotide is left out)
What is the most likely result of a frameshift mutation? - Correct Answers -Early stop
codon, shorter/non functional protein
What happens if a deletion/insertion with a multiple of 3 occurs ? - Correct Answers -
protein will have one extra AA or one less, situational mutation that depends on the
structure and effect
what are Large Scale mutations? - Correct Answers --caused by aberrant recombination
events (repair of DNA double strand breaks)
-or large insertions of other chromosomes
-translocations
What are consequences of a large scale insertions and translocations? - Correct
Answers --imbalance in gene expression
-expression of oncogenes
What is an oncogene? - Correct Answers -blocks cell regulation, replication always
active (brick left on the gas)
What is a BCR/ABL translocation? - Correct Answers --lose part of ABL gene (ABL AND
BCR on same chromosome)
-loss of cell cycle control
-leukemia results
What is Burkitt's translocation? - Correct Answers --Myc (oncogene) fused to active
promoter
-High Myc expression
-Lymphoma
What types of Damage is DNA constantly exposed to ? - Correct Answers --reactive
chemical species that are results of normal metabolic processes
-environmental factors
-breaks created on purpose
How many times are lesions(damage) repaired in the cell? - Correct Answers -10^4 to
10^6 times per day
