chapter 10 homework

Which relations will be found in the percentages of bases of a double‑stranded DNA molecule?

(A+G)/(C+T)=1.0 A+C=G+T A/T=G/C

Select each of the characteristics that are key features of genetic material.

- It must be able to replicate and transmit to progeny. - It must encode the blueprint to form proteins and other structures. - It must periodically mutate to generate a variation.

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%,22%, what are the percentages of the remaining bases?

T = 22% G = 28% C = 28%

Identify the key structural features of a DNA molecule.

The backbone of DNA is made of a sugar and a phosphate molecule. DNA bases are always paired using Watson-Crick base pairing. DNA strands are antiparallel and include a 5′ end and a 3′ end.

What contribution did James Watson and Francis Crick make to our understanding of DNA?

They pieced together the available evidence and modeled the structure of DNA.

The bacteria Streptococcus pneumoniae has a virulent S strain and a nonvirulent R strain. The S strain is lethal to mice. The S strain contains a chemical factor that can transform the R strain to be virulent. The diagram shows a series of experiments conducted by injecting combinations of these strains into mice to identify the transforming factor. A R strain (nonvirulent) B S strain (virulent) C Heat‑treated S strain D R strain and heat‑treated S strain E R strain and heat‑treated S strain with polysaccharides, lipids, RNA, and proteins destroyed F R strain and heat‑treated S strain with polysaccharides, lipids, RNA, proteins, and DNA destroyed If DNA is the transforming factor, match the expected results of each experiment by placing the appropriate mouse image.

A = alive B = dead C = alive D = dead E = dead F = alive

Which of the statements describes purines and pyrimidines in DNA molecules?

Purines form hydrogen bonds with pyrimidines. Purines consist of a two-ring structure.

Enter the complementary sequence to the DNA strand shown. 5′- TACAGACAG -3′

atgtctgtc

What is the key feature of DNA that allows it to be copied?

complementary base pairing

James Watson and Francis Crick used this X‑ray diffraction image taken by Rosalind Franklin to deduce the structural properties of B‑form DNA. What findings did Watson and Crick make from this image?

includes 10 base pairs per repeat has a consistent diameter shaped like a helix