{"id":195614,"date":"2025-02-28T13:48:09","date_gmt":"2025-02-28T13:48:09","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=195614"},"modified":"2025-02-28T13:48:11","modified_gmt":"2025-02-28T13:48:11","slug":"what-is-the-composition-of-glycine-at-ph-10-0","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/28\/what-is-the-composition-of-glycine-at-ph-10-0\/","title":{"rendered":"What is the composition of glycine at pH 10.0"},"content":{"rendered":"\n

Shown below is the titration curve for the amino acid glycine (side chain -H). What is the composition of glycine at pH 10.0?<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

100% H3N-CH2-COO
50% H3N-CH2-COO: 50% H2N-CH2-COO
50% H2N-CH2-COOH; 50% H2N-CH2-COO
100% H2N-CH2-COOH<\/p>\n\n\n\n

The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n

At pH 10.0, glycine predominantly exists in the form H\u2082N-CH\u2082-COO\u207b. This corresponds to the fully deprotonated state, where the amino group (-NH\u2082) is neutral, and the carboxylate group (-COO\u207b) carries a negative charge.<\/p>\n\n\n\n

Glycine, the simplest amino acid, has two ionizable groups: a carboxyl group (-COOH) and an amino group (-NH\u2082). The carboxyl group has a pKa\u2081 around 2.34, and the amino group has a pKa\u2082 near 9.60. The pKa value represents the pH at which half of the molecules of that group are deprotonated.<\/p>\n\n\n\n

The titration curve of glycine reflects these ionization events. At low pH, glycine exists primarily in its fully protonated form, H\u2083N\u207a-CH\u2082-COOH. As the pH increases and surpasses pKa\u2081, the carboxyl group loses a proton, resulting in the zwitterionic form, H\u2083N\u207a-CH\u2082-COO\u207b, which predominates around the isoelectric point (pI) of approximately 6.0. Upon further increase in pH and exceeding pKa\u2082, the amino group deprotonates, leading to the fully deprotonated form, H\u2082N-CH\u2082-COO\u207b.<\/p>\n\n\n\n

At pH 10.0, which is above pKa\u2082, the equilibrium favors the deprotonated amino group. Therefore, glycine molecules predominantly exist as H\u2082N-CH\u2082-COO\u207b, carrying a net negative charge. This understanding is crucial in biochemical applications, such as protein purification and enzyme activity studies, where the charge state of amino acids influences molecular interactions and function.<\/p>\n\n\n\n

For a visual representation of glycine’s titration curve and its species distribution across different pH levels, you can refer to the following resource:<\/p>\n","protected":false},"excerpt":{"rendered":"

Shown below is the titration curve for the amino acid glycine (side chain -H). What is the composition of glycine at pH 10.0? 100% H3N-CH2-COO50% H3N-CH2-COO: 50% H2N-CH2-COO50% H2N-CH2-COOH; 50% H2N-CH2-COO100% H2N-CH2-COOH The Correct Answer and Explanation is : At pH 10.0, glycine predominantly exists in the form H\u2082N-CH\u2082-COO\u207b. This corresponds to the fully deprotonated […]<\/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-195614","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/195614","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=195614"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/195614\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=195614"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=195614"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=195614"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}