Week 3 Flashcards
In Eukaryotic cells , DNA is bound to proteins, forming a complex called ______.
Chromatin
What phase do the Sister chromatids condense into discrete visible chromosomes ?
Metaphase
What are the 4 free bases of DNA?
Adenine
Guanine
Cytosine
Thymine
What is the name for the sugar in DNA?
Deoxyribose (missing the hydroxyl group on carbon 2 that is found on ribose)
What are Nucleotides composed of?
Base + Sugar+ phosphate
What are Nucleosides composed of ?
Base+ Sugar (no phosphate)
If the sugar is a deoxyribose rather than ribose, the nucleoside has a “ _____ “ as a prefix , example for Adenine to Adenosine is ?
Deoxy
DeoxyAdenosine
What is the monomer unit of nucleic acids?
Nucleotides
What is the inorganic phosphate attached to in Nucleotides ?
5’-hydroxyl group of the sugar in ester linkage
In Nucleosides, the nitrogenous base is linked by a ________ bond to the anomeric carbon of the sugar.
N-glycosidic
What type of bond connects the Nucleotide chains to form DNA backbone?
Phosphate backbone - linked by phosphodiester bonds
What is a phosphodiester bond ?
linkage of 3’Carbon of one sugar and the 5’ Carbon of the next sugar with Oxygen from a phosphate group
What type of bond exists between bases that holds them together ?
Hydrogen bond
How many bonds does Thymine and Adenine have ?
2 bonds - Hydrogen bonds (weaker than covalent and allow for seperation )
How many bonds does Guanine and Cytosine have ?
3 bonds- Hydrogen bonds
What is the Nucleoside name for Adenine ?
Adenosine
What is the Nucleoside name for Guanine ?
Guanosine
What is the nucleoside name for Thymine?
Thymidine
What is the nucleoside name for Uracil ?
Uridine
What is the nucleoside name for Hypoxanthine ?
Inosine
What forces stabilize the double helix?
Stacked bases have Van Der Waals forces and hydrophobic effects on interior of helix
-additionally the hydrogen bonds between bases
What allows for the negative charge and binding of proteins to the outside of DNA ?
the Phosphate group has an exposed -OH on outside that will lose the H ion at physiological pH- negative charge, facilitates binding specific proteins
What forces cause DNA to separate ?
Alkali (increased -OH) and heat cause denaturing (strands separate)
What is the different effect of Alkalki on DNA vs RNA?
RNA- phosphodiester bonds are broken
DNA- strands separate