Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
13 Cards in this Set
- Front
- Back
|
What does a nucleotide consist of?
|
a heterocyclic nitrogenous base (purine or pyrimidiine),
a pentose sugar (ribose or deoxyribose (furanose form) and a phosphate group |
|
|
All the bases strongly absorb UV light at...
|
250-276nm, 260nm peak
|
|
|
what is the difference between a ribonucleoside and a deoxyribonucleoside?
What is the difference between a nucleoside and a nucleotide? |
A deoxyribonucleoside has a oxygen missing @ 2 position.
Nucleoside = base + sugar Nucleotide = base + sugar + phosphate |
|
|
How many negative charges does a nucleoside-triphosphate have?
|
4 negative charges. one each on alpha and beta phosphate and two on gamma phosphate.
|
|
|
Which bond joins the base to the sugar in a nuclotide?
|
beta-N-glycosidic bod between C1 of ribose and N of base (N1 of pyrimidines and N-9 of purines)
|
|
|
What is the main difference between purines and pyrimidines? List examples of each.
|
Purines have a double ring structure and pyrimidines have a single ring structure.
Adenine and Guanine are purines. Uracil, Thymine, and Cytosine are pyrimidines. |
|
|
Two strands of DNA are held together by what type of bonds between which bases?
|
Hydrogen bond between A-T and G-C. G-C forms a triple hydrogen bond and therefore it's stronger.
|
|
|
What is the diameter of the watson/crick double helix? How many base-pairs per turn?
|
2.0nm
10.4 bp/turn |
|
|
At what site of the DNA do the proteins bind to the DNA?
|
proteins bind at major and minor groove caused by glycosidic bonds on both strands, which are not directly across from each other.
|
|
|
Increase in which bonds of DNA increases the melting temperature of DNA?
|
Increase in G-C content increases melting temperature of DNA. Because of the triple hydrogen bonding of G-C compared to double hydrogen bonding of A-T.
|
|
|
What is viscosity? What happens to the DNA viscosity when it is denatured?
|
Viscosity if the material's resistance to flow.
Viscosity decreases as DNA is denatured. |
|
|
Clinal correlation:
5-Fluorouracil AZT (Zidovudine) Acyclovir |
5-Fluorouracil - cancer therapy. converted to FdUMP which inhibits thymidylate synthase.
AZT - AIDS treatment. inhibits replication of HIV Acyclovir - inhibits DNA polymerase of Herpes Simplex. |
|
|
Clinical correlation:
Azathioprine Allopurinol Adenosine (Adenocard) |
Azathioprine - metabolized to 6-mercaptopurine which suppresses rejection during organ transplant.
Allopurinol - treatment of gout Adenosine - treat supraventricular tachycardia. |
