Biochem1

Question 1

Pyrimidine histones are rich in what AAs?

Answer 1

Lysine & Arginine

Question 2

What histone protein is not in the nucleosome core?

Answer 2

H1 - ties nucleosome beads together in a string

Question 3

Heterochromatin

Answer 3

Highly Condensed - Inactive and Inaccessible

Question 4

Euchromatin

Answer 4

Active and Accessible

Question 5

Histone Methylation

Answer 5

Inactivates transcription of DNA

“Methylation makes DNA Mute”

Question 6

Histone acetylation

Answer 6

Relaxes DNA coiling, allowing for transcription

“Acetylation makes DNA Active”

Question 7

Purines

Answer 7

Adenine & Guanine - 2 rings

“Ashley Green is PURe”

Question 8

Pyrimidines

Answer 8

Cytosine, Thymine, Uracil - 1 ring

“CUT the PY”

Question 9

What nucleotide has a methyl group?

Answer 9

Thymine

Question 10

Deamination of what nucleotide makes Uracil?

Answer 10

Cytosine via deamination

Question 11

What AA are required for purine synthesis?

Answer 11

Glycine, Aspartate, Glutamine - GAG

Question 12

Nucleoside =

Answer 12

base + ribose (Sugar)

Question 13

Nucleotide =

Answer 13

base + ribose + phosphaTe (via 3’-5’ bond)

Question 14

Ribonucleotides are converted to deoxyribonucleotide by what enzyme?

Answer 14

Ribonucleotide Reductase

Question 15

What 2 metabolic pathways is Carbamoyl phosphate involved in?

Answer 15

De novo pyrimidine synthesis & Urea cycle

Question 16

What enzyme deficiency leads to accumulation of carbamoyl phosphate?

Answer 16

Ornithine transcarbamoylase deficiency (OTC); key enzyme in Urea Cycle

Question 17

What drug inhibits Ribonucleotide Reductase?

Answer 17

Hydroxyurea

Question 18

What drug blocks de novo purine synthesis?

Answer 18

6-mercaptopurine (6-MP)

Question 19

What drug inhibits thymidylate synthase?

Answer 19

5-Fluorouracil (5-FU);

Decreases deoxythymidine monophosphate (dTMP)

Question 20

Orotic Aciduria: Pathology

Answer 20

Autosomal Recessive

Inability to convert Orotic Acid to UMP (de novo pyrimidine synthesis pathway) because of defect in UMP synthase (bifunctional enzyme)

Question 21

Orotic Aciduria: Findings

Answer 21

INcrease in Orotic Acid in urine
Megaloblastic Anemia (B12 no help)
Failure to thrive
NO hyperammonemia (Vs. OTC deficiency - increased orotic acid w/ hyperammonemia)

Question 22

Orotic Aciduria: Treatment

Answer 22

Oral uridine

Question 23

Guanine has a what group?

Answer 23

Ketone

Question 24

In DNA what does Guanine bind to?

Answer 24

Cytosine

Question 25

In DNA what does Adenosine bind to?

Answer 25

Thymine (RNA - Uracil)

Question 26

What is stronger C-G or A-T?

Answer 26

C-G - 3 H+ bonds; A-T - 2 H+ bonds

Question 27

Pyrimidine base production requires what?

Answer 27

Aspartate