Molecular Biochemistry-First Aid Flashcards
What two amino acids are histones rich in?
Lysine and arginine
What is a nucleosome?
Consists of DNA wound twice around a histone octamer
Which type of histone connects consecutive nucleosomes?
H1
What’s the difference between heterochromatin and euchromatin?
Heterochromatin is highly condensed and not acc
What does DNA methylation do for mismatch repair?
New DNA is methylated (cytosine and adenine) and it later loses its methylation, allowing DNA mismatch repair enzymes to distinguish between new and old DNA
What does histone methylation do?
Inactivates transcription of DNA; “makes DNA mute”
What does histone methylation do?
Activates DNA transcription by relaxing DNA coiling; makes DNA active
Which base has a methyl group
Thymine
Which base has a ketone
Guanine
From which base is uracil made and how?
Uracil is made by deamination of cytosine
Which base pair has 2 H bonds?
A and T
Which three amino acids are necessary for purine synthesis?
Glycine, aspartate and glutamine
What does 6-MP do?
6-mercaptopurine blocks de novo purine synthesis
What does DNA methylation at CpG islands do?
Repress transcription
Name the intermediates along the pathway to pyrimidine base synthesis starting with carbamoyl phosphate
Carbamoyl phosphate–>orotic acid (add PRPP)–>UMP–>UDP–> CTP or dUDP–> dUPD becomes dUMP–> dTMP
