Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 24: Problem 60

Indicate whether each statement is true or false. (a) Tryptophan is an aromatic amino acid. (b) Lysine is positively charged at pH 7. (c) Asparagine has two amide bonds. (d) Isoleucine and leucine are enantiomers. (e) Valine is probably more water-soluble than arginine.

Short Answer

Expert verified
(a) True, (b) True, (c) False, (d) False, (e) False

Step by step solution

01

Statement (a)

Tryptophan is an aromatic amino acid. An aromatic amino acid is an amino acid that contains an aromatic ring in its side chain. Tryptophan has an indole ring, which is an aromatic ring, in its side chain. Hence, **(a) is true**.
02

Statement (b)

Lysine is positively charged at pH 7. Lysine is a basic amino acid that has a positively charged side chain at a neutral pH of around 7. Its side chain contains an ammonium ion (NH3+). Therefore, **(b) is true**.
03

Statement (c)

Asparagine has two amide bonds. Asparagine is an amino acid with an amide group in its side chain. Its side chain structure is \( \mathrm{H}_{2}\mathrm{N-CO-R} \), where R is the amino acid backbone. There is only one amide bond in its side chain. Therefore, **(c) is false**.
04

Statement (d)

Isoleucine and leucine are enantiomers. Enantiomers are non-superposable mirror images of each other. Isoleucine and leucine are both aliphatic amino acids with similar molecular structures, but they are not mirror images of each other. They simply have different side-chain arrangements; they are isomers, but not enantiomers. Thus, **(d) is false**.
05

Statement (e)

Valine is probably more water-soluble than arginine. Water solubility of amino acids depends on their hydrophilicity or hydrophobicity. In general, amino acids with polar or charged side chains are more water-soluble, whereas those with nonpolar side chains are less water-soluble. Valine is a nonpolar, hydrophobic amino acid, while arginine is a basic amino acid with a positively charged side chain, making it more hydrophilic and more water-soluble. Therefore, **(e) is false**.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Pure acetic acid is a viscous liquid, with high melting and boiling points \(\left(16.7^{\circ} \mathrm{C}\right.\) and $\left.118^{\circ} \mathrm{C}\right)$ compared to compounds of similar molecular weight. Suggest an explanation.

An unknown organic compound is found on elemental analysis to contain $72.0 \%\( carbon, \)12.0 \%\( hydrogen, and \)16.0 \%$ oxygen by mass. It has a molecular weight of \(100 \mathrm{~g} / \mathrm{mol}\) and is slightly soluble in water. Upon careful oxidation it is converted into a ketone which contains \(73.4 \%\) carbon, \(10.3 \%\) hydrogen, and \(16.3 \%\) oxygen by mass. Indicate two or more reasonable structures for the unknown.

Indicate whether each statement is true or false. (a) Ethane has a higher molar mass than ethene. (b) For molecules of the same homologous family, the higher the molecular mass, the higher the boiling point. (c) The local geometry around the alkene group is T-shaped. (d) Butene has two structural isomers.

Which of the following peptides have a net positive charge at $\mathrm{pH} 7 ?$ (a) Asn-His-Arg, (b) Glu-Lys-Phe, (c) Thr-Leu-Ala.

You are working in a biotechnology lab and are analyzing DNA. You obtain a sample of a short dodecamer of DNA that contains 12 base pairs. (a) What must the ratio of adenine to thymine be in your sample? (b) What must the ratio of cytosine to guanine be in your sample? (c) Assume the counterions present in your DNA solution are sodium ions. How many sodium ions must there be per dodecamer? Assume the \(5^{\prime}\) end phosphates each bear a-1 charge.
See all solutions

Recommended explanations on Chemistry Textbooks

Making Measurements

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Inorganic Chemistry

Read Explanation

Chemical Reactions

Read Explanation

Nuclear Chemistry

Read Explanation

The Earths Atmosphere

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free