set with Questions and correct/verified
Answers
which 2 elements were identified in an acidic compound that was isolated from the nucleus by Johann
Miescher? - ANSWER-nitrogen and phosphorus
why proteins were thought to encode information that pertains to inheritable traits? - ANSWER--
inheritable traits are diverse, and therefore molecules that encode these traits must be diverse
-proteins made of 20 amino acids, structurally diverse
which 2 macromolecules make the Bacteriophage structure? - ANSWER-protein and DNA
In a cell, which macromolecules are labeled 35S-methionine and 32P, respectively? - ANSWER-proteins
and DNA
Describe the Hershey-Chase experiments. what conclusions were made from this study? - ANSWER--
radioactively labeled bacteriophages:
-radioactive 35S incorporated into bacteriophage proteins
-radioactive 32P incorporated into bacteriophage DNA
-all radioactive viruses to infect bacteria
what is the DNA nucleotide made of? - ANSWER-5-carbon sugar (2'-deoxyribose), phosphate, N-
containing base
which bases are purines and pyrimidines, respectively? explain why they are classified this way. -
ANSWER-purines - adenine (A) and guanine (G): have C and N forming 2 rings
pyrimidines - thymine (T) and cytosine (C): have C and N forming single ring
Which base is found only in RNA? - ANSWER-Uracil
in his study of DNA structure, what major findings were made by Erwin Chargaff? - ANSWER--amount of
A relative to G differs among species (purines NOT show stoichiometric relationships). purine will base
pair with specific pyrimidine
A=T G=C
Linus Pauling built a DNA model and it failed. what was wrong with his proposed model? - ANSWER-
negatively charged phosphate groups facing inward would repel each other and DNA would be unstable
in their study of DNA structure, which three points did Watson and Crick focus one? - ANSWER-DNA size,
shape (helix or parallel), bonding requirements (how strands help together)
what type of DNA did Maurice Wilkins laboratory work with? - ANSWER-dehydrated DNA
What type of DNA did Rosalind Franklin's laboratory work with? - ANSWER-dry and wet DNA
, based on Franklins data, what were the calculated principal dimensions of the DNA molecule? -
ANSWER-length of full twist = 3.4nm
distance between adjacent bases = 0.34nm
diameter of DNA = 2nm
based on Franklins data, how many bases are per turn of the helix? - ANSWER-3.4nm/0.34nm= 10 bases
based on Franklins data, what was the orientation of phosphate groups in the DNA molecule? - ANSWER-
outward
based on Franklins data, how many strands were thought to be twisted into a helix? - ANSWER-2, 3, or 4
parallel strands
who recognized the significance of Franklins data? - ANSWER-Maurice Wilkins
How many strands is DNA molecule made of and in which direction do DNA strands run? - ANSWER-2
helically twisted strands running in opposite direction (antiparallel)
which groups are located on the outside of the DNA molecule? - ANSWER-sugar-phosphate
where are nitrogenous bases located in the DNA molecule, and what hold the bases together? -
ANSWER-inside, hydrogen bonds
which bacterial DNA polymerase was described by Aurthur Kornberg? - ANSWER-DNA polymerase I
explain what the origins of replication (ori) is - ANSWER-binding sites for proteins that initiate the
replication process
what is the function of DNA polymerase III in bacteria? - ANSWER-synthesizes Okazaki fragments by
extension of RNA primers, and newly synthesized Okazaki fragments contain RNA-DNA segments
what is the function of DNA polymerase I in bacteria? - ANSWER-RNA primers are removed by DNA
polymerase I, has both 5' to 3' exonuclease activity
in eukaryotic cells, which DNA polymerase are found in the nucleus? - ANSWER-α, δ, and ε
in eukaryotic cells, which DNA polymerase are found in the mitochondria? - ANSWER-y
describe the 2 fundamental properties that are shared by all DNA polymerases - ANSWER-1. synthesize
DNA only in the 5' to 3' direction
2. all DNA Polymerases add new nucleotides only to a pre-formed RNA primer strand that is hydrogen-
bonded to a parent DNA template
what is the enzyme called, which unwinds the parent DNA strand? - ANSWER-helicase
what is the direction called in which the parent DNA strand unwinds? - ANSWER-replication fork
movement
in which direction is a parent DNA strand copied? - ANSWER-5' to 3'