Genomic Dysfunction

Question 1

What is the “central dogma” of genetics?

Answer 1

DNA- transcription-RNA-translation-protein

Question 2

Why is DNA condensed during the cell cycle?

Answer 2

To prevent DNA damage when it is being separated

Question 3

What amino acids primarily compose a histone protein and why is this ideal?

Answer 3

The primary AAs are arginine and lysine which give the protein a more positive charge. This complements the negatively charged backbone of the DNA strand.

Question 4

What is the main difference between euchromatin and heterochromatin?

Answer 4

euchromatin is less packed than heterochromatin. This occurs because euchromatin is more actively transcribed than the rest of the genome.

Question 5

What year was the DNA structure released by Watson and Crick?

Answer 5

1953

Question 6

What is RNA splicing?

Answer 6

A piece of transcribed RNA that is altered post-transcription. Introns will be excized out and exons will be spliced together to form different genes.

Question 7

What is HDAC?

Answer 7

Histone Deacetylace- will remove acetyl group from lysine residue on histones to deactivate the section of DNA

Question 8

What is HAT?

Answer 8

Histone Acetyl Transferase- Adds an acetyl group to the histone protein to activate the DNA.

Question 9

Methylation

Answer 9

Adds methyl group to the DNA molecule which will repress gene expression

Question 10

Hypermethylation

Answer 10

Will cause transcriptional silencing and can be inherited by daughter cells during cell division

Question 11

Topoisomerase

Answer 11

relieves overwound supercoils during DNA transcription

Question 12

Irinotecan

Answer 12

Topoisomerase- I inhibitor- used in colorectal cancer

Question 13

Etoposisde

Answer 13

Topoisomerase- II inhibitor- used in leukemia

Question 14

What do topoisomerase inhibitors do?

Answer 14

block the cell cycle; create single and double brand breaks; leads to apoptosis and cell death

Question 15

What kind of DNA damage does UV radiation cause?

Answer 15

pyrimidine dimers form

Question 16

Depurination

Answer 16

loss of a purine from DNA strand

Question 17

Deamination

Answer 17

loss of an amine group from the nucleotide-
Adenine to hypoxanthine
Guanine to xanthine
Cytosine to uracil

Question 18

What is direct repair of DNA damage?

Answer 18

corrects with DNA photolyase or methylguanine methyltransferase depending on the type of damage (pyrimidine dimers or O6-methylguanine

Question 19

Base excision repair

Answer 19

correction of single base mismatches or nondistorting alterations- corrected using DNA glycolases

Question 20

Nucleotide excision repair

Answer 20

Chemical adducts that distort DNA- corrected using NER protein complexes, DNA polymerase and DNA ligase

Question 21

Mismatch excision repair

Answer 21

mismatched base in daughter strand- corrected using MER protein complexes, DNA polymerase and DNA ligase

Question 22

Recombination repair

Answer 22

Double strand breaks- corrected using multiple different systems

Question 23

Transcription coupled repair

Answer 23

stalled RNA polymerase during transcription

Question 24

xeroderma pigmentosum

Answer 24

Defects to the NER complex leading to sensitivity to light

Question 25

Hereditary nonpolyposis colorectal cancer

Answer 25

Defects to the MER complex

Question 26

Breast Cancer/ BRCA1

Answer 26

defects from recombination repair

Question 27

Cockayne Syndrome

Answer 27

Mutation to the ERCC6 and ERCC8 genes that result in defects to the TCR repair system