Chapter 22

Draw the structures of two of the tripeptides that can be formed from alanine, glycine, and cysteine.

Draw the structures of two of the tripeptides that can be formed from valine, alanine, and serine.

Draw the two forms of glucose, clearly indicating how they differ.

Draw a disaccharide formed from \(\beta\) -galactose and ribose.

I Mannose has the same molecular formula as glucose and the same geometry except at carbon-2, where the \(\mathrm{H}\) and OH groups are interchanged. Draw the structures of \(\alpha\) - and \(\beta\) -mannose.

Draw and name the five principal bases used in DNA and RNA. Be specific about the bases used in DNA and those used in RNA.

Draw the nucleotides that contain the following bases and sugars. (a) Adenine and ribose (b) Cytosine and deoxyribose (c) Uracil and ribose

Write the structural formula for each of the following molecules. (a) cis-2-bromo-3-hexene (b) 2 -nitrophenol

Explain why ethanol dissolves freely in water, whereas its isomer, dimethyl ether, is only slightly soluble in water.

Draw the structure of an \(\alpha\) -amino acid with a chiral center.

Write the structures of two monomers that you think might be used to make an interesting copolymer. Draw the repeating unit of the copolymer.

Explain the correlation between the three-letter base pairs in a codon and the order of \(\alpha\) -amino acids in proteins.

How many different tripeptides can be formed that contain one glycine, one valine, and one alanine?

Write the reaction for bromination of propene. What mass of bromine is needed to completely react with \(22.1 \mathrm{~g}\) propene?

Write the product of the reaction of equimolar amounts of chlorine gas and 1 -butyne. Are cis and trans isomers possible in the product? How does the hybridization of the alkyne carbon atoms change in the transition from reactant to product?

Describe the most important intermolecular force between molecules of (a) 2 -methyl-2-propanol. (b) 2 -butanone.