DNA has unique properties that allow it to accurately retain genetic information, even after multiple rounds of replication. One aspect of DNA that allows it to accurately store genetic information is the base pairing from Chargaff's first rule of the four nucleotide bases.If the A content of a DNA molecule is 22%, what are the percentages of the remaining bases?
In the 1920s, a dye was developed that bound to DNA and stained nuclei in direct proportion to the amount of DNA present in cells. Interestingly, all cells derived from the same multicellular organisms stained to the same levels. However, cells from different organisms absorbed different amount of stain. Gametes (sex cells - sperm and egg cells) absorbed half of the amount of dye as compared to the somatic cells (all other cells in the body except the gametes). Such experiments _____.A. demonstrated that somatic cells and gametes could not have differing amounts of DNA.B. demonstrated that all species had the same amount of nuclear DNA.C. provided circumstantial evidence that DNA is the genetic material.D. proved DNA is the genetic material.
Imagine a plant with two incompletely-dominant loci. CW (white flowers) is incompletely dominant to CR (red flowers). Heterozygous have pink flowers. HS (short) is incompletely dominant to HT (tall. Heterozygotes are of medium height.A medium height pink plant is crossed with a mystery plant (i.e. its genotype and phenotype aren't revealed to you). 1/4 of the offspring are white with medium height; 1/4 are white with tall height; 1/4 are pink with medium height; and 1/4 are pink with tall height. What are the genotypes of each parent?
Which type of process shows that DNA was the genetic material?A. bacterial transductionB. bacterial transformationC. eukaryotic meiosis
In their experiments directed at determining whether DNA or protein serves as genetic material, Hershey and Chase chose isotopes of sulfur and phosphorus to label protein and DNA molecules, respectively. Could they have utilized isotopes of carbon and nitrogen instead? If not, briefly explain.
The mechanism of replication was determined by Meselson and Stahl. Imagine if their data had turned out differently. Which model would be supported by these hypothetical results?Original : 1 band of N15 only1st generation : 1 band of N15/N142nd generation : 1 band of N15/N14A. ConservativeB. Semi-conservativeC. DispersiveD. Cannot tell from this data alone
Which of the following would correctly describe the results of Meselson and Stahl's famous experiment after one cycle of replication in 14N medium, if DNA was conservative?A. DNA molecules containing two 14N-DNA strands only.B. DNA molecules containing one strand of 15N-DNA and one strand of 14N-DNA.C. DNA molecules containing two 15N-DNA strands only.D. DNA molecules containing individual strands composed of a mixture of both 14N-DNA and 15N-DNA.E. An equal number of DNA molecules containing two 15N-DNA and DNA molecules containing 14N-DNA strands.
Watson and Crick, the discoverers of DNA structure, proposed a semiconservative model of replication. Meselson and Stahl carried out experiments to test this by labeling DNA with isotopes of nitrogen 14N and 15N.Labeled DNA were isolated from bacteria and centrifuged.Match the experimental condition with the result observed in the centrifuge tube.DNA isolated from E. coli grown in 15N mediumDNA isolated from E. coli grown in 14N mediumDNA isolated from E. coli grown first in 15N medium then transferred to 14N medium for one generation.Choose fromA. single upper band of DNAB. intermediate band of DNAC. single lower band of DNAD. two bands of DNA (upper and lower)
In cats, curled ears result from an allele, Cu, that is dominant over an allele cu, for normal ears. Black color results from an independently assorting allele, G, that is dominant over an allele for gray, g. A gray cat homozygous for curled ears is mated with a homozygous black cat with normal ears. All the F1 cats are black and have curled ears.What phenotypes and proportions are expected from teh following two crosses?1 - Two of the F1 cats mate?2 - An F1 cat mates with a stray cat that is gray and possesses normal ears.A. 1/4 black cats, curled ears; 1/4 black cats, normal ears; 1/4 gray cats, curled ears; and 1/4 gray cats normal earsB. 9/16 gray cats, normal ears; 3/16 gray cats, curled ears; 3/16 black cats, normal ears; and 1/16 black cats, curled earsC. 9/16 black cats, curled ears; 3/16 black cats, normal ears; 3/16 gray cats, curled ears; and 1/16 gray cats, normal earsD. All gray cats, normal earsE. All black cats, curled ears.
In Mycobacterium tuberculosis H37Rv, the cytosine represents about 66% of the total pyrimidine content of DNA. Using Chargaff's rules, determine the percentage of total nucleotides in the DNA represented by adenine?