Chapter 10 - The Chemical Nature of the Gene Flashcards
Before the chemical nature of genetic material was known, scientists knew that genetic material must be capable of doing what 3 things? ___ large amounts of ___; ____ faithfully; and ____ the ____.
(1) Encode (store) lots of complex info; (2) replicate w/ high fidelity (faithfully); (3) encode the phenotype
According to Chargaff’s rules, if a genome is 25% adenine, what is the percentage of each of the other three nucleotides? If 22% adenine?
25% each.
22% thymine; 28% cytosine; 28% guanine
If Avery, MacLeod, and McCarty had found that samples of heat-killed bacteria treated with DNase or RNase transformed bacteria, but samples treated with protease did not, what conclusion would they have made?
Genetic material must be composed of protein.
Suppose Hershey and Chase found that phage ghosts contained 32P label but the label was absent from infected E. coli. Furthermore, suppose they found 35S lacking in the ghosts and present in the infected E. coli. They would have concluded:
A. that protein was the genetic material in phage.
B. that DNA was the genetic material in phage.
C. that somehow the radioactivity prevented DNA from getting into E. coli.
D. that protein and DNA together made up the genetic material.
A. that protein was the genetic material in phage.
How do the sugars of RNA and DNA differ?
The sugar of RNA has a hydroxyl group on C 2’ that is not found in the sugar of DNA
A new virus has been discovered in a species of bacteria that inhabit hot springs. The viral genome is found to consist of four ribonucleotides in the following ratios: 8% A, 42% C, 42% G, and 8% U. The genome is most likely ___________, but it could be ____________.
A. double-stranded DNA; double-stranded DNA
B. double-stranded RNA.; single-stranded RNA
C. single-stranded DNA; single-stranded RNA
D. single-stranded RNA; double-stranded DNA
B. double-stranded RNA.; single-stranded RNA
A new virus has been discovered in a species of bacteria that inhabit hot springs. The viral genome is found to consist of four ribonucleotides in the following ratios: 8% A, 42% C, 42% G, and 8% U. The genome is most likely \_\_\_\_\_\_\_\_\_\_\_, but it could be \_\_\_\_\_\_\_\_\_\_\_\_. A. dsDNA; dsDNA B. dsRNA.; ssRNA C. ssDNA; ssRNA D. ssRNA; dsDNA
B. dsRNA.; ssRNA
A new virus has been discovered in a species of bacteria that inhabit hot springs. The viral genome is in the following ratios: 8% A, 52% C, 30% G, and 10% U. The genome is most likely ___________.
ssRNA
By the late 1800s, DNA was discovered, and it was known that it contained ____ and ____ (50%/50%), and four ___ ____.
DNA; protein; nitrogenous bases
Until the mid 1900s, it was thought that genes were made of _____ because DNA seemed to be too simple.
Additionally, Levene incorrectly theorized the ____ hypothesis (where bases repeated in ___ amounts), mainly because of the ___ he used and the lack of ____ in his samples.
protein.
tetranucleotide; equal; technology; diversity
In the 40s and 50s, Chargaff was able to overcome 2 of Leven’s problems by using ___ technology and with increased sample ____. He was able to conclude that the percent of __ and __ bases varied greatly depending on the source of DNA, and were not ___/___ as Levene’s tetranucleotide theory stated.
TLC; diversity
G + C; 50/50
Griffith’s experiment with S. pneumoniae serotypes IIR and IIIS lead to the discovery of the _____ principle. In his experiment, he mixed __-__ strains of IIIS with IIR, and after infecting mice, he recovered ___. This is how ____ got its name.
transforming.
heat-killed; IIIS.
transformation
In an experiment by Avery, MacLeod, and McCarthy, the ___ Principle was identified by creating a ____ from IIIS (only ___ molecules are needed), adding RNase, protease, and DNase to each of 3 aliquots, and added an aliquot to each of 3 cultures of IIR. IIIS was recovered in all but the ___-treated culture. They were able to conclude that ___ is the ___ factor.
Transforming; filtrate; soluble
DNase-treated
DNA; transforming
The Hershey-Chase experiment further cemented DNA as the genetic material by preparing 2 cultures of T2 with E. coli: one with a ___ label (binds to protein); and one with a ___ label (binds to DNA). The T2 were isolated, and new batches of E. coli were infected. Aliquots of each culture were centrifuged, and the supernate and pellet were tested. ___ was found in the supernate; ___ was found in the pellet indicating that ___ was the molecule being injected by T2 and passed to progeny.
35S; 32P.
35S; 32P; DNA
Watson & Crick were able to elucidate the 3D structure of DNA from X-ray ____; the work was done by ____ and ____.
diffraction
Wilkins; Franklin
The primary structure of DNA is the ___ ____; secondary is the ___ ___; tertiary is ___ ___.
nucleotide sequence; helical structure; chromatin organization.
DNA is a polymer of ____, and is the largest ____ in the cell.
Nucleotides; macromolecules
Name the 3 components of nucleotides.
Nitrogenous base, pentose sugar, and a phosphate (1, 2, or 3).
Regarding nucleotide structure: the carbons joined to the oxygen found in pentose are __ and __, and the __ carbon is joined to the __ carbon.
1’ and 4’; 5’ joined to 4’
