{"id":220292,"date":"2025-05-28T05:44:39","date_gmt":"2025-05-28T05:44:39","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=220292"},"modified":"2025-05-28T05:59:35","modified_gmt":"2025-05-28T05:59:35","slug":"answer-the-following-questions-about-the-amino-acid-whose-fischer-projection-formula-is","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/28\/answer-the-following-questions-about-the-amino-acid-whose-fischer-projection-formula-is\/","title":{"rendered":"Answer the following questions about the amino acid whose Fischer projection formula is"},"content":{"rendered":"\n<p>Answer the following questions about the amino acid whose Fischer projection formula is<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/05\/image-465.png\" alt=\"\" class=\"wp-image-220298\"\/><\/figure>\n\n\n\n<p>a. Is it a D-amino acid or an L-amino acid? b. Is it a nonpolar or polar amino acid? c. Is it an essential or nonessential amino acid? d. Is it a standard or nonstandard amino acid?<\/p>\n\n\n\n<p>At room temperature, amino acids are solids with relatively high decomposition points. Explain why.<\/p>\n\n\n\n<p>At room temperature, most amino acids are not very soluble in water. Explain why.<\/p>\n\n\n\n<p><strong>The Correct Answer and Explanation is:<\/strong><\/p>\n\n\n\n<p>The amino acid shown in the Fischer projection is <strong>cysteine<\/strong>, with the structure:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>  COOH\n   |\nH2N\u2014C\u2014H\n   |\n  CH2\n   |\n  SH\n<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">a. Is it a D-amino acid or an L-amino acid?<\/h3>\n\n\n\n<p><strong>Answer: L-amino acid<\/strong><\/p>\n\n\n\n<p>Explanation: In the Fischer projection, if the amino group (-NH\u2082) is on the <strong>left<\/strong> of the chiral carbon, the amino acid is in the <strong>L-configuration<\/strong>. This matches the configuration of naturally occurring amino acids in proteins.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">b. Is it a nonpolar or polar amino acid?<\/h3>\n\n\n\n<p><strong>Answer: Polar amino acid<\/strong><\/p>\n\n\n\n<p>Explanation: Cysteine contains a thiol (-SH) group, which can form hydrogen bonds and is moderately polar. It can participate in redox reactions (forming disulfide bonds), contributing to its polarity.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">c. Is it an essential or nonessential amino acid?<\/h3>\n\n\n\n<p><strong>Answer: Nonessential amino acid<\/strong><\/p>\n\n\n\n<p>Explanation: Cysteine is considered <strong>nonessential<\/strong> because the human body can synthesize it, mainly from methionine (an essential amino acid).<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">d. Is it a standard or nonstandard amino acid?<\/h3>\n\n\n\n<p><strong>Answer: Standard amino acid<\/strong><\/p>\n\n\n\n<p>Explanation: Cysteine is one of the <strong>20 standard amino acids<\/strong> used in protein biosynthesis.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Why are amino acids solids with high decomposition points at room temperature?<\/h3>\n\n\n\n<p>Amino acids exist in their <strong>zwitterionic form<\/strong> at room temperature, where the amino group is protonated (-NH\u2083\u207a) and the carboxyl group is deprotonated (-COO\u207b). These opposite charges result in <strong>strong electrostatic (ionic) interactions<\/strong> between molecules, much like salts. These strong interactions require a lot of energy to overcome, giving amino acids <strong>high melting (decomposition) points<\/strong> and making them solids at room temperature.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Why are most amino acids not very soluble in water at room temperature?<\/h3>\n\n\n\n<p>While amino acids are polar, their solubility in water is <strong>limited<\/strong> due to the <strong>zwitterionic nature<\/strong>, which promotes strong intermolecular attractions. These interactions can make it energetically unfavorable for water molecules to break apart amino acid clusters, especially for amino acids with <strong>nonpolar side chains<\/strong>. Additionally, the crystalline structure in the solid state also reduces solubility, as dissolving requires disrupting a stable ionic lattice.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>Summary<\/strong>:<br>Cysteine is an L-form, polar, nonessential, and standard amino acid. Amino acids are solids with high decomposition points due to strong ionic interactions in their zwitterionic form. Limited solubility in water arises from strong intermolecular forces and the nature of their side chains.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/05\/learnexams-banner4-52.jpeg\" alt=\"\" class=\"wp-image-220299\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Answer the following questions about the amino acid whose Fischer projection formula is a. Is it a D-amino acid or an L-amino acid? b. Is it a nonpolar or polar amino acid? c. Is it an essential or nonessential amino acid? d. Is it a standard or nonstandard amino acid? At room temperature, amino acids [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-220292","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/220292","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=220292"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/220292\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=220292"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=220292"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=220292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}