Chapter 10 Flashcards
a key discovery leading to the structure of DNA was done by chargaff
he found that ___
the tetranucleotide hypothesis was false
the amount of A equals the amount of T, and the amount of G equals the amount of C
in Avery, Macleod, and mccartys experiments, homogenates from heat-killed bacteria were treated with different enzymes, and then the ability of those homogenates to transform bacteria assayed
under which condition would transformation not occur?
treatment with DNase
the major contribution of Franklin and Wilkins to the study of DNA was
an X-ray diffraction pattern
the sugar in DNA is called “deoxyribose” because it
is missing a 2’ -OH group
what is purine?
a base with two rings
adenine or guanine
a strong covalent bond between adjacent nucleotides is
a phosphodiester bond
what does the term antiparallel mean?
the strands run in opposite directions
the 5’ end of one strand is opposite the 3’ end of the second strand
the number of hydrogen bonds between complementary G-C pairs is
three
a structure formed by a single-strand DNA or RNA molecule that has complementary sequences is
a hairpin
key features of genetic material
must encode the blueprint to form proteins and other structures
it must be able to replicate and transmit progeny
it must periodically mutate genetic variation
if the (A) content of a DNA molecule is 18%, what are the percentages of the remaining bases?
A=T
G=C
T= 18%
G= 100 - (18+18)= 64/2= 32%
C=32%
identify the pieces of evidence describing the features of DNA that Watson and crick used to determine the structure of DNA
- the diameter of the DNA double helix is 2 nanometers, with each purine-pyrimidine base pairing spanning an equivalent distance between the two chains
- DNA forms a right - handed double helical structure with two polynucleotides chains coiled around a central axis
- the sugar-phosphate backbones of each DNA helix run antiparallel to one another
- a purine base forms hydrogen bonds to pair with a pyrimidine base located on the opposite DNA strand. specifically A pairs with T, and C pairs with G
what is the key feature of DNA that allows it to be copied ?
complementary base pairing
identify the unknown nucleic acid nitrogenous base adenine= 28.0% cytosine= 18.0% guanine=26.0% thymine= 0.0% uracil= 28.0%
single-stranded RNA
which of the statements describes purines and pyrimidines in DNA molecules?
purines form hydrogen bonds with pyrimidines
purines consist of two-ring structure
