DNA and RNA Structure

What did Chargaff discover while studying bases in the DNA of organisms? The bases in the DNA of each organism were unique. The ratios of thymine and adenine were similar, as were the ratios of guanine and cytosine. The overall percentages of bases were different from one organism to the next. There were equal amounts of all four bases in every organism, or 25 percent of each base.

The ratios of thymine and adenine were similar, as were the ratios of guanine and cytosine.

A DNA strand has the sequence ACCGAGCTT. Which is the complementary strand of RNA? TGGCTCGAA UGGCUCGAA GTTAGTGCC CAATCTAGG

UGGCUCGAA

Which structural characteristic is seen in RNA but not in DNA? double strands a single strand chains of nucleotides a helical shape

a single strand

Which discovery is attributed to Phoebus Levene? extraction and observation of DNA identification of ribose and deoxyribose recognition of RNA as DNA's messenger construction of an accurate DNA model

identification of ribose and deoxyribose

DNA is a nucleic acid polymer composed of which repeating structural unit? nucleotides phosphate groups ribosomes proteins

nucleotides

Which of the following could be a nucleotide of RNA? deoxyribose + phosphate group + thymine deoxyribose + phosphate group + uracil ribose + phosphate group + thymine ribose + phosphate group + uracil

ribose + phosphate group + uracil

A single strand of DNA helix has the code CGCTAA. Which would be the complementary code on the other strand of the helix? CGCAUU TATCGG ATAGCC GCGATT

GCGATT

Which base is found only in RNA? ribose thymine uracil deoxyribose

uracil