Chapter 10 Flashcards
Kossel figure out
determined that it contained four nitrogenous bases - adenine, cytosine, guanine, and thymine
Levene figure out
- DNA consists of large number of repeating units called nucleotides
what do nucleotides contain
sugar, phosphate, and base
Chargaff’s rules
- adenine always equal to thymine (A=T) and cytosine equal to guanine (G=C)
what did avery, maclead, and mccarty figure out
provided evidence that the transforming principle- genetic information- resides in DNA
- provides first evidence that DNA is the genetic material
what does the process of transformation indicate?
that the transforming principle is capable of altering bacteria
what was the purpose of the HERSHEY AND CHASE EXPERIMENT
to determine whether the phage protein or the phage DNA is transmitted in phage reproduction
- used radioactive isotopes
what did hershey and chase prove in their experiment
demonstrated that DNA not protein, enters the bacterial cell during phage reproduction and that only DNA is passed on to progeny phages
what did watson and crick discover
three-dimensional structure of DNA using X-ray diffraction images
what does DNA consist of?
- two complementary and antiparallel nucleotide strands that form a double helix
- nucleotides joined together by phosphodiester linkages
nucleotides with a sugar, a phosphate group, and a nitrogen containing base
difference between rna and DNA
RNA sugar (ribose) has a hydroxyl group (OH) attached to the 2’- carbon atom and DNA’s sugar has a hydrogen atom (H)
what types of nitrogenous bases are there?
Purine:consist of six member ring attached to five member ring (A and G)
Pyrimidine: six member ring only (C, T, U)
- Thymine is restricted to DNA and Uracil is found only in RNA
what connects nucleotides together
phosphodiester linkages: strong covalent bonds
- polynucleotide strands connected by phosphodiester bonds that connects the 3’ carbon atom of one nucleotide to the 5’ phosphate group of next
describe DNA structure
- double helix
- sugar phosphate linkages are on outside of helix, and the bases are stacked in the interior of the molecule
- antiparallel (two polynucleotide strands run in opposite directions)
- two bonds between A-T
three bonds between C-G - complementary DNA strands
hairpin
forms when sequences of nucleotides on the same strand are inverted complements
- consists of a region of paired bases and intervening unpaired bases (loop at the end of the stem)
