Flashcards in Chapters 16-18 Deck (94)
bonds formed between the phosphate on the 5' carbon of one nucleotide and the 3' carbon of the next nucleotide
nitrogenous base with two rings, includes adenine and guanine
nitrogenous base with single ring structure, includes thymine, cytosine and uracil
3 phosphate groups + pentose sugar + nitrogenous base
pentose sugar + nitrogenous sugar
1 phosphate, pentose sugar, and nitrogenous base
(the bond holding phosphates breaks to make energy for building process)
first scientists credited with DNA structure
James Watson and Francis Crick
polarity of nucleotide chain
one end contains the roof of the pentose sugar (5' carbon) and the other end is the left base of the pentose sugar (3' carbon)
how many nucleotides chains are in RNA?
how many nucleotide chains are in DNA?
DNA is a double helix formed by combining two chains
how are two nucleotide chains linked?
hydrogen bonds between their bases (A,G,T,C)
run in opposite directions. 5' end and 3' end of opposite nucleotide chains are side-by-side
DNA is antiparallel
how does the sugar-phosphate backbone remain straight?
A purine always bonds with pyrimidine. always 3 rings in any pair, providing consistent width
What complementary base pair has 2 hydrogen bonds?
Adenine and Thymine
NOT URACIL because only DNA does this
What complementary base pair has 3 hydrogen bonds?
Guanine and Cytosine
equal to 0.1 nanometers. used to measure wavelengths of EM radiation
distance between base pairs (steps of ladder)
distance between sugar-phosphate backbones
distance between every complete twist of helix
3.4 angstroms between pairs, so 10 pairs per twist
#purines = #pyrimidines
#adenines = #thymines
#cytosines = #guanines
ratio is very unlikely to be 1:1:1:1
Scientists used to think genetic material was ______
First proof that nucleic acid was genetic material and not protein
Bacterial transformation studies ny Frederick Griffith - 1928
Involved bacteria with glyco protein coats and without
Denaturation study by Oswald Avery, Colin Macleod, and Maclyn McCarty - 1944
Protein was destroyed with enzyme but bacteria transformation occurred
RNA was destroyed but bacteria transformation occurred
DNA was destroyed and transformation didn't occur
Genetic material must be DNA
bacteriophage labeling by Hershey and Chase - 1952
radioactive sulfur was put into bacteriophage making protein coat radioactive
radioactive phosphorous was put into virus making nucleic acid radioactive
phosphorus was found in new phages, so DNA is genetic material
Tobacco Mosaic Virus Study by Fraenkel-Conrat and Singer - 1957
TMV protein coat put onto HRV RNA to make hybrid.
When virus replicates it is HRV RNA and protein coat. Therefore RNA was genetic material.
when DNA makes copies of itself during synthesis stage of the cell cycle
Two strands of DNA reassociate, therefore parental double helix is always together.
two strands of parental DNA molecule separate and act as a template for new complementary strand.
therefore each DNA strand is half parental and half new material
each strand of DNA contains both old and newly synthesized DNA
old is dispersed throughout the strand