{"id":18967,"date":"2025-06-13T11:34:58","date_gmt":"2025-06-13T11:34:58","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=18967"},"modified":"2025-06-13T11:35:02","modified_gmt":"2025-06-13T11:35:02","slug":"which-of-these-is-a-factual-statement-and-not-a-major-difference-between-smooth-muscle-and-skeletal-muscle","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/which-of-these-is-a-factual-statement-and-not-a-major-difference-between-smooth-muscle-and-skeletal-muscle\/","title":{"rendered":"Which of these is a factual statement and not a major difference between smooth muscle and skeletal muscle"},"content":{"rendered":"\n<p>Which of these is a factual statement and not a major difference between smooth muscle and skeletal muscle? a. Ca2+ binds to calmodulin in smooth muscle and skeletal muscle b. Smooth and skeletal muscle can only be activated by depolarization of the membrane c. Phosphorylation of myosin leads to binding to actin d. Cytosolic Ca2+ controls contractile activate in both skeletal and smooth muscle<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\"><strong>The correct answer and explanation is:<\/strong><\/mark><\/p>\n\n\n\n<p><strong>Correct Answer: d. Cytosolic Ca\u00b2\u207a controls contractile activity in both skeletal and smooth muscle<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation (300 words):<\/strong><\/h3>\n\n\n\n<p>Muscle contraction in both <strong>smooth<\/strong> and <strong>skeletal muscle<\/strong> is triggered by an increase in <strong>cytosolic calcium ions (Ca\u00b2\u207a)<\/strong>. This is a <strong>factual similarity<\/strong>, not a major difference, which is why <strong>option D<\/strong> is correct.<\/p>\n\n\n\n<p>When a muscle is stimulated to contract, <strong>cytosolic Ca\u00b2\u207a concentration increases<\/strong>, leading to activation of the contractile machinery. However, the <strong>mechanism of activation<\/strong> differs between smooth and skeletal muscle:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In <strong>skeletal muscle<\/strong>, Ca\u00b2\u207a binds to <strong>troponin C<\/strong>, which causes a conformational change in the <strong>troponin-tropomyosin complex<\/strong>, exposing binding sites on actin filaments and allowing myosin heads to attach and initiate contraction.<\/li>\n\n\n\n<li>In <strong>smooth muscle<\/strong>, troponin is absent. Instead, Ca\u00b2\u207a binds to <strong>calmodulin<\/strong>, forming a Ca\u00b2\u207a-calmodulin complex that activates <strong>myosin light chain kinase (MLCK)<\/strong>. MLCK then <strong>phosphorylates the myosin light chains<\/strong>, enabling myosin to bind to actin and initiate contraction.<\/li>\n<\/ul>\n\n\n\n<p>Now, let\u2019s break down why the other options are incorrect:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>a. &#8220;Ca\u00b2\u207a binds to calmodulin in smooth muscle and skeletal muscle&#8221;<\/strong>: Incorrect. This is true only for <strong>smooth muscle<\/strong>. In skeletal muscle, Ca\u00b2\u207a binds to <strong>troponin<\/strong>, not calmodulin.<\/li>\n\n\n\n<li><strong>b. &#8220;Smooth and skeletal muscle can only be activated by depolarization of the membrane&#8221;<\/strong>: Incorrect. While skeletal muscle contraction depends heavily on depolarization, <strong>smooth muscle can be activated<\/strong> by various stimuli including hormones, stretch, and local chemical signals, not just membrane depolarization.<\/li>\n\n\n\n<li><strong>c. &#8220;Phosphorylation of myosin leads to binding to actin&#8221;<\/strong>: This is <strong>true for smooth muscle<\/strong>, but not for skeletal muscle, where <strong>phosphorylation is not required<\/strong> for myosin to bind actin.<\/li>\n<\/ul>\n\n\n\n<p>Therefore, <strong>statement D<\/strong> is the only <strong>factual similarity<\/strong>, not a distinguishing difference, between the two muscle types.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Which of these is a factual statement and not a major difference between smooth muscle and skeletal muscle? a. Ca2+ binds to calmodulin in smooth muscle and skeletal muscle b. Smooth and skeletal muscle can only be activated by depolarization of the membrane c. Phosphorylation of myosin leads to binding to actin d. Cytosolic Ca2+ [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-18967","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/18967","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=18967"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/18967\/revisions"}],"predecessor-version":[{"id":18968,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/18967\/revisions\/18968"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=18967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=18967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=18967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}