Name: genes, introns, and regulatory dna
Uploaded: 2026-08-26T08:20:12.834Z
Duration: 2 min 39 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Structure and Function

3.1.9-12.A

Organization of Genes

&#x625;&#x644;&#x649; &#x62C;&#x627;&#x646;&#x628; &#x627;&#x644;&#x62A;&#x646;&#x633;&#x64A;&#x642; &#x627;&#x644;&#x645;&#x639;&#x642;&#x62F; &#x644;&#x644;&#x645;&#x627;&#x62F;&#x629; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x64A;&#x629; &#x62F;&#x627;&#x62E;&#x644; &#x646;&#x648;&#x627;&#x629; &#x627;&#x644;&#x62E;&#x644;&#x64A;&#x629;&#x60C;&#x62A;&#x64F;&#x638;&#x647;&#x631; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x627;&#x644;&#x628;&#x634;&#x631;&#x64A;&#x629; &#x623;&#x64A;&#x636;&#x64B;&#x627; &#x62A;&#x646;&#x633;&#x64A;&#x642;&#x647;&#x627; &#x627;&#x644;&#x641;&#x631;&#x64A;&#x62F;. &#x645;&#x646;&#x62A;&#x634;&#x631;&#x629; &#x628;&#x64A;&#x646; &#x627;&#x644;&#x643;&#x631;&#x648;&#x645;&#x648;&#x632;&#x648;&#x645;&#x627;&#x62A; &#x64A;&#x648;&#x62C;&#x62F; 20, 000 &#x62C;&#x64A;&#x646;&#x60C;&#x623;&#x62D;&#x64A;&#x627;&#x646;&#x64B;&#x627; &#x64A;&#x641;&#x635;&#x644;&#x647;&#x627; &#x645;&#x633;&#x627;&#x641;&#x627;&#x62A; &#x634;&#x627;&#x633;&#x639;&#x629; &#x644;&#x644;&#x62D;&#x645;&#x636; 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&#x628;&#x645;&#x648;&#x642;&#x639; &#x628;&#x62F;&#x621; &#x646;&#x633;&#x62E; &#x642;&#x631;&#x64A;&#x628;&#x60C;&#x64A;&#x628;&#x62F;&#x623; &#x641;&#x64A; &#x625;&#x646;&#x62A;&#x627;&#x62C; &#x634;&#x631;&#x64A;&#x637; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A;&#x60C;&#x645;&#x633;&#x62A;&#x62E;&#x62F;&#x645;&#x64B;&#x627; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x643;&#x646;&#x645;&#x648;&#x630;&#x62C;. &#x62B;&#x645; &#x64A;&#x62C;&#x62A;&#x627;&#x632; &#x627;&#x644;&#x628;&#x648;&#x644;&#x64A;&#x645;&#x631;&#x627;&#x632; &#x627;&#x644;&#x645;&#x627;&#x62F;&#x629; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x64A;&#x629;&#x60C;&#x648;&#x64A;&#x633;&#x62A;&#x645;&#x631; &#x641;&#x64A; &#x625;&#x646;&#x62A;&#x627;&#x62C; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A; &#x62D;&#x62A;&#x649; &#x64A;&#x62A;&#x639;&#x631;&#x641; &#x639;&#x644;&#x649; &#x62A;&#x633;&#x644;&#x633;&#x644; &#x625;&#x646;&#x647;&#x627;&#x621; &#x646;&#x633;&#x62E; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x60C;&#x641;&#x64A;&#x648;&#x642;&#x641; &#x627;&#x644;&#x639;&#x645;&#x644;&#x64A;&#x629;. &#x648;&#x645;&#x646; &#x627;&#x644;&#x645;&#x647;&#x645;&#x60C;&#x623;&#x646; &#x628;&#x64A;&#x646; &#x646;&#x642;&#x627;&#x637; &#x627;&#x644;&#x628;&#x62F;&#x627;&#x64A;&#x629; &#x648;&#x627;&#x644;&#x646;&#x647;&#x627;&#x64A;&#x629; &#x62A;&#x644;&#x643;&#x60C;&#x62A;&#x642;&#x628;&#x639; &#x645;&#x633;&#x627;&#x62D;&#x627;&#x62A; &#x62A;&#x64F;&#x633;&#x645;&#x649; &#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x648;&#x625;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A;&#x60C;&#x648;&#x643;&#x644;&#x627;&#x647;&#x645;&#x627; &#x645;&#x646;&#x639;&#x643;&#x633; &#x641;&#x64A; &#x645;&#x646;&#x62A;&#x62C; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A;.&#x648;&#x645;&#x639; &#x630;&#x644;&#x643;&#x60C;&#x641;&#x625;&#x646; &#x627;&#x644;&#x639;&#x645;&#x644;&#x64A;&#x627;&#x62A; &#x627;&#x644;&#x62A;&#x627;&#x644;&#x64A;&#x629; &#x62A;&#x632;&#x64A;&#x644; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x645;&#x646; &#x647;&#x630;&#x627; &#x627;&#x644;&#x646;&#x633;&#x62E;. &#x648;&#x62D;&#x64A;&#x62B; &#x623;&#x646; &#x647;&#x630;&#x627; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A; &#x633;&#x64A;&#x633;&#x62A;&#x62E;&#x62F;&#x645; &#x644;&#x625;&#x646;&#x62A;&#x627;&#x62C; &#x627;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;&#x627;&#x62A;&#x60C;&#x64A;&#x64F;&#x634;&#x627;&#x631; &#x625;&#x644;&#x649; &#x627;&#x644;&#x625;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x643;&#x645;&#x646;&#x627;&#x637;&#x642; &#x644;&#x644;&#x62A;&#x634;&#x641;&#x64A;&#x631;&#x60C;&#x628;&#x64A;&#x646;&#x645;&#x627; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x647;&#x64A; &#x645;&#x62B;&#x627;&#x644; &#x622;&#x62E;&#x631; &#x639;&#x644;&#x649; &#x627;&#x644;&#x645;&#x648;&#x627;&#x62F; &#x63A;&#x64A;&#x631; &#x627;&#x644;&#x642;&#x627;&#x628;&#x644;&#x629; &#x644;&#x644;&#x62A;&#x634;&#x641;&#x64A;&#x631;. &#x648;&#x62A;&#x62C;&#x62F;&#x631; &#x627;&#x644;&#x625;&#x634;&#x627;&#x631;&#x629; &#x644;&#x623;&#x646;&#x648;&#x627;&#x639; &#x623;&#x62E;&#x631;&#x649; &#x645;&#x646; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x63A;&#x64A;&#x631; &#x627;&#x644;&#x642;&#x627;&#x628;&#x644; &#x644;&#x644;&#x62A;&#x634;&#x641;&#x64A;&#x631; &#x645;&#x62B;&#x644; &#x627;&#x644;&#x643;&#x627;&#x62A;&#x645;&#x627;&#x62A; &#x645;&#x631;&#x62A;&#x628;&#x637;&#x629; &#x623;&#x64A;&#x636;&#x64B;&#x627; &#x628;&#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A;.&#x627;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;&#x627;&#x62A; &#x627;&#x644;&#x645;&#x64F;&#x633;&#x645;&#x627;&#x647; &#x645;&#x62B;&#x628;&#x637;&#x627;&#x62A; &#x62A;&#x631;&#x62A;&#x628;&#x637; &#x628;&#x647;&#x630;&#x647; &#x627;&#x644;&#x645;&#x646;&#x627;&#x637;&#x642;&#x60C;&#x644;&#x62A;&#x645;&#x646;&#x639; &#x627;&#x631;&#x62A;&#x628;&#x627;&#x637; &#x645;&#x639;&#x632;&#x632;-&#x627;&#x644;&#x628;&#x648;&#x644;&#x64A;&#x645;&#x631;&#x627;&#x632;&#x60C;&#x645;&#x645;&#x627; &#x64A;&#x645;&#x646;&#x639; &#x627;&#x644;&#x646;&#x633;&#x62E;. &#x646;&#x62A;&#x64A;&#x62C;&#x629; &#x644;&#x630;&#x644;&#x643;&#x60C;&#x62A;&#x633;&#x627;&#x639;&#x62F; &#x627;&#x644;&#x643;&#x627;&#x62A;&#x645;&#x627;&#x62A; &#x639;&#x644;&#x649; &#x62A;&#x646;&#x638;&#x64A;&#x645; &#x627;&#x644;&#x62A;&#x639;&#x628;&#x64A;&#x631; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x64A;. &#x648;&#x647;&#x643;&#x630;&#x627;&#x60C;&#x64A;&#x62A;&#x643;&#x648;&#x646; &#x627;&#x644;&#x62C;&#x64A;&#x646; &#x645;&#x646; &#x645;&#x643;&#x648;&#x646;&#x627;&#x62A; &#x639;&#x62F;&#x64A;&#x62F;&#x629;.&#x645;&#x646; &#x628;&#x64A;&#x646;&#x647;&#x627; &#x627;&#x644;&#x645;&#x639;&#x632;&#x632; &#x648;&#x627;&#x644;&#x625;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x648;&#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x648;&#x627;&#x644;&#x639;&#x646;&#x627;&#x635;&#x631; &#x627;&#x644;&#x62A;&#x646;&#x638;&#x64A;&#x645;&#x64A;&#x629;&#x60C;&#x627;&#x644;&#x62A;&#x64A; &#x645;&#x639;&#x64B;&#x627; &#x62A;&#x633;&#x627;&#x639;&#x62F; &#x639;&#x644;&#x649; &#x62A;&#x62D;&#x62F;&#x64A;&#x62F; &#x62A;&#x639;&#x628;&#x64A;&#x631; &#x627;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646; &#x641;&#x64A; &#x627;&#x644;&#x62E;&#x644;&#x64A;&#x629;.

1. وليام روي وسكوت ووالتر جيلبرت. "تطور الإنترونات الصبغية: الأنماط والألغاز والتقدم". مراجعات الطبيعة علم الوراثة 7 ، العدد 3 (مارس 2006): 211-21. <a href = "https://doi.org/10.1038/nrg1807" >https://doi.org/10.1038/nrg1807</a>.

تنظيم الجينات

<h4>&#x646;&#x638;&#x631;&#x647; &#x639;&#x627;&#x645;&#x647;</h4>

&#x64A;&#x645;&#x643;&#x646; &#x647;&#x64A;&#x643;&#x644;&#x629; &#x62C;&#x64A;&#x646;&#x648;&#x645;&#x627;&#x62A; &#x62D;&#x642;&#x64A;&#x642;&#x64A;&#x627;&#x62A; &#x627;&#x644;&#x646;&#x648;&#x649; &#x641;&#x64A; &#x639;&#x62F;&#x629; &#x641;&#x626;&#x627;&#x62A; &#x648;&#x638;&#x64A;&#x641;&#x64A;&#x629;. &#x64A;&#x62A;&#x643;&#x648;&#x646; &#x62E;&#x64A;&#x637; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x645;&#x646; &#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x648;&#x645;&#x646;&#x627;&#x637;&#x642; &#x645;&#x62A;&#x62F;&#x627;&#x62E;&#x644;&#x629; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A;. &#x62A;&#x62A;&#x643;&#x648;&#x646; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x646;&#x641;&#x633;&#x647;&#x627; &#x645;&#x646; &#x625;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x645;&#x634;&#x641;&#x631;&#x629; &#x644;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646; &#x648;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x63A;&#x64A;&#x631; &#x645;&#x634;&#x641;&#x631;&#x629;. &#x64A;&#x62A;&#x645; &#x627;&#x633;&#x62A;&#x626;&#x635;&#x627;&#x644; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x628;&#x645;&#x62C;&#x631;&#x62F; &#x646;&#x633;&#x62E; &#x627;&#x644;&#x62A;&#x633;&#x644;&#x633;&#x644; &#x625;&#x644;&#x649; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A; &#x627;&#x644;&#x645;&#x631;&#x633;&#x627;&#x644; &#x60C; &#x62A;&#x627;&#x631;&#x643;&#x627;&#x64B; &#x627;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x641;&#x642;&#x637; &#x644;&#x62A;&#x631;&#x645;&#x64A;&#x632; &#x627;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;&#x627;&#x62A;.

<h4>&#x64A;&#x62A;&#x645; &#x641;&#x635;&#x644; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x62D;&#x642;&#x64A;&#x642;&#x64A;&#x629; &#x627;&#x644;&#x646;&#x648;&#x627;&#x629; &#x639;&#x646; &#x637;&#x631;&#x64A;&#x642; &#x627;&#x644;&#x645;&#x646;&#x627;&#x637;&#x642; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x64A;&#x629;</h4>

&#x641;&#x64A; &#x62C;&#x64A;&#x646;&#x648;&#x645;&#x627;&#x62A; &#x62D;&#x642;&#x64A;&#x642;&#x64A;&#x627;&#x62A; &#x627;&#x644;&#x646;&#x648;&#x649; &#x60C; &#x64A;&#x62A;&#x645; &#x641;&#x635;&#x644; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x639;&#x646; &#x637;&#x631;&#x64A;&#x642; &#x627;&#x645;&#x62A;&#x62F;&#x627;&#x62F;&#x627;&#x62A; &#x643;&#x628;&#x64A;&#x631;&#x629; &#x645;&#x646; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x62A;&#x64A; &#x644;&#x627; &#x62A;&#x631;&#x645;&#x632; &#x644;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;&#x627;&#x62A;. &#x648;&#x645;&#x639; &#x630;&#x644;&#x643; &#x60C; &#x641;&#x625;&#x646; &#x647;&#x630;&#x647; &#x627;&#x644;&#x645;&#x646;&#x627;&#x637;&#x642; &#x628;&#x64A;&#x646; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x62A;&#x62D;&#x645;&#x644; &#x639;&#x646;&#x627;&#x635;&#x631; &#x645;&#x647;&#x645;&#x629; &#x62A;&#x646;&#x638;&#x645; &#x646;&#x634;&#x627;&#x637; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x60C; &#x639;&#x644;&#x649; &#x633;&#x628;&#x64A;&#x644; &#x627;&#x644;&#x645;&#x62B;&#x627;&#x644; &#x60C; &#x627;&#x644;&#x645;&#x62D;&#x641;&#x632; &#x627;&#x644;&#x630;&#x64A; &#x64A;&#x628;&#x62F;&#x623; &#x641;&#x64A;&#x647; &#x627;&#x644;&#x646;&#x633;&#x62E; &#x60C; &#x648;&#x627;&#x644;&#x645;&#x639;&#x632;&#x632;&#x627;&#x62A; &#x648;&#x627;&#x644;&#x645;&#x62B;&#x628;&#x637;&#x627;&#x62A; &#x627;&#x644;&#x62A;&#x64A; &#x62A;&#x636;&#x628;&#x637; &#x627;&#x644;&#x62A;&#x639;&#x628;&#x64A;&#x631; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x64A;. &#x641;&#x64A; &#x628;&#x639;&#x636; &#x627;&#x644;&#x623;&#x62D;&#x64A;&#x627;&#x646; &#x64A;&#x645;&#x643;&#x646; &#x623;&#x646; &#x62A;&#x648;&#x62C;&#x62F; &#x645;&#x648;&#x627;&#x642;&#x639; &#x627;&#x644;&#x631;&#x628;&#x637; &#x647;&#x630;&#x647; &#x628;&#x639;&#x64A;&#x62F;&#x627;&#x64B; &#x639;&#x646; &#x627;&#x644;&#x62C;&#x64A;&#x646; &#x627;&#x644;&#x645;&#x631;&#x62A;&#x628;&#x637;.

<h4>&#x62A;&#x62A;&#x62E;&#x644;&#x644; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x625;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x62A;&#x631;&#x645;&#x64A;&#x632; &#x627;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;</h4>

&#x639;&#x646;&#x62F;&#x645;&#x627; &#x62D;&#x642;&#x642; &#x627;&#x644;&#x628;&#x627;&#x62D;&#x62B;&#x648;&#x646; &#x641;&#x64A; &#x639;&#x645;&#x644;&#x64A;&#x629; &#x646;&#x633;&#x62E; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x627;&#x62A; &#x641;&#x64A; &#x62D;&#x642;&#x64A;&#x642;&#x64A;&#x627;&#x62A; &#x627;&#x644;&#x646;&#x648;&#x649; &#x60C; &#x623;&#x62F;&#x631;&#x643;&#x648;&#x627; &#x623;&#x646; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A; &#x627;&#x644;&#x645;&#x631;&#x633;&#x627;&#x644; &#x627;&#x644;&#x646;&#x647;&#x627;&#x626;&#x64A; (mRNA) &#x627;&#x644;&#x630;&#x64A; &#x64A;&#x631;&#x645;&#x632; &#x644;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646; &#x647;&#x648; &#x623;&#x642;&#x635;&#x631; &#x645;&#x646; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x630;&#x64A; &#x64A;&#x64F;&#x634;&#x62A;&#x642; &#x645;&#x646;&#x647;. &#x64A;&#x631;&#x62C;&#x639; &#x647;&#x630;&#x627; &#x627;&#x644;&#x627;&#x62E;&#x62A;&#x644;&#x627;&#x641; &#x641;&#x64A; &#x627;&#x644;&#x637;&#x648;&#x644; &#x625;&#x644;&#x649; &#x639;&#x645;&#x644;&#x64A;&#x629; &#x62A;&#x633;&#x645;&#x649; &#x627;&#x644;&#x631;&#x628;&#x637;. &#x628;&#x645;&#x62C;&#x631;&#x62F; &#x646;&#x633;&#x62E; pre_mRNA &#x645;&#x646; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x641;&#x64A; &#x627;&#x644;&#x646;&#x648;&#x627;&#x629; &#x60C; &#x64A;&#x632;&#x64A;&#x644; &#x627;&#x644;&#x62A;&#x636;&#x641;&#x64A;&#x631; &#x639;&#x644;&#x649; &#x627;&#x644;&#x641;&#x648;&#x631; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x648;&#x64A;&#x636;&#x645; &#x627;&#x644;&#x627;&#x643;&#x633;&#x648;&#x646;&#x627;&#x62A; &#x645;&#x639;&#x627;&#x64B;. &#x648;&#x627;&#x644;&#x646;&#x62A;&#x64A;&#x62C;&#x629; &#x647;&#x64A; &#x627;&#x644;&#x62D;&#x645;&#x636; &#x627;&#x644;&#x646;&#x648;&#x648;&#x64A; &#x627;&#x644;&#x631;&#x64A;&#x628;&#x64A; &#x627;&#x644;&#x645;&#x631;&#x633;&#x627;&#x644; &#x627;&#x644;&#x645;&#x631;&#x645;&#x632; &#x644;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646; &#x627;&#x644;&#x630;&#x64A; &#x64A;&#x646;&#x62A;&#x642;&#x644; &#x625;&#x644;&#x649; &#x627;&#x644;&#x633;&#x64A;&#x62A;&#x648;&#x628;&#x644;&#x627;&#x632;&#x645; &#x648;&#x64A;&#x64F;&#x62A;&#x631;&#x62C;&#x645; &#x625;&#x644;&#x649; &#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;.

<h4>&#x64A;&#x645;&#x643;&#x646; &#x623;&#x646; &#x64A;&#x62E;&#x62A;&#x644;&#x641; &#x639;&#x62F;&#x62F; &#x627;&#x644;&#x625;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x644;&#x643;&#x644; &#x62C;&#x64A;&#x646; &#x628;&#x634;&#x643;&#x644; &#x643;&#x628;&#x64A;&#x631;</h4>

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<h4>&#x627;&#x644;&#x627;&#x646;&#x62A;&#x631;&#x648;&#x646;&#x627;&#x62A; &#x62A;&#x62D;&#x645;&#x644; &#x648;&#x638;&#x627;&#x626;&#x641; &#x647;&#x627;&#x645;&#x629;</h4>

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<h4>&#x627;&#x644;&#x63A;&#x627;&#x644;&#x628;&#x64A;&#x629; &#x627;&#x644;&#x639;&#x638;&#x645;&#x649; &#x645;&#x646; &#x627;&#x644;&#x62C;&#x64A;&#x646;&#x648;&#x645; &#x627;&#x644;&#x628;&#x634;&#x631;&#x64A; &#x644;&#x627; &#x62A;&#x631;&#x645;&#x632; &#x644;&#x644;&#x628;&#x631;&#x648;&#x62A;&#x64A;&#x646;&#x627;&#x62A;</h4>

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Overview

The genomes of eukaryotes can be structured in several functional categories. A strand of DNA is comprised of genes and intergenic regions. ...

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Education

JoVE Core

Biology

علم الأحياء

Genetics

علم الوراثة

DNA Structure and Function

بنية الحمض النووي ووظيفته

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

genes, introns, and regulatory dna

Eukaryotic genes are arranged within DNA along with non-coding regions that help control gene activity. A DNA strand includes genes and intergenic regions, which are the stretches between genes. These regions do not code for proteins, but they can contain important regulatory elements such as promoters, enhancers, and silencers.

A gene itself is not a single continuous coding block. It usually contains protein-coding exons and non-coding introns. After DNA is transcribed into pre-mRNA in the nucleus, splicing removes the introns and joins the exons together. The shorter mRNA then moves to the cytoplasm, where it is translated into protein.

The number of introns in a gene can vary a lot. The human DMD gene is more than two million base pairs long and encodes dystrophin, a muscle protein. Mutations in DMD can cause muscular dystrophy, a disease that leads to progressive muscle deterioration. This gene has 79 exons and 103 introns. In contrast, the histone H1A gene is only 781 base pairs long and has one exon and no introns.

Introns are not always useless DNA. Some introns contain elements that help regulate genes. They also support alternative splicing, a process that mixes and matches exons after transcription. This lets one coding sequence produce several protein variants.

Most of the human genome does not code for proteins. Early genome research called many of these sequences junk DNA, but scientists now know that much of this non-coding DNA has important roles. At least 9% of the human genome is involved in gene regulation, which is far more than the protein-coding portion.

Genes, Introns, and Regulatory DNA

the dna helix

How DNA Stores Genetic Information

DNA stores genetic information that is passed from one generation to the next in organisms and most viruses. It is built from two strands of nucleotides that twist together into a double helix. The story of how scientists uncovered this structure developed step by step over nearly a century. Each DNA strand is made of nucleotides. A nucleotide contains the sugar deoxyribose, a phosphate group, and one of four nitrogen bases: adenine (A), guanine (G), cytosine (C), or thymine (T). Adenine and...

dna packaging

Chromatin and Histones in DNA Packing

Eukaryotic cells must pack long DNA molecules into the nucleus, and chromatin makes that possible. DNA wraps around proteins called histones to form nucleosomes, which are the main unit of DNA packaging. Nucleosomes then coil into compact chromatin fibers. The amount of DNA in a cell is much larger than it first seems. A single human skin cell has about 3 billion base pairs of DNA, and if that DNA were stretched out in a line, it would be about 2 meters long. With about 50 trillion cells in...

organization of genes

Eukaryotic genes are arranged within DNA along with non-coding regions that help control gene activity. A DNA strand includes genes and intergenic regions, which are the stretches between genes. These regions do not code for proteins, but they can contain important regulatory elements such as promoters, enhancers, and silencers. A gene itself is not a single continuous coding block. It usually contains protein-coding exons and non-coding introns. After DNA is transcribed into pre-mRNA in the...

karyotyping

Chromosome Stains for Detecting Disorders

Chromosome staining helps scientists find genetic disorders by showing the number and physical features of chromosomes. These features appear after DNA condenses into chromosomes during mitosis. Cytogeneticists then stop mitosis and stain the chromosomes to study their banding pattern. The pattern reveals details such as chromosome number, shape, and type. A chromosome description like this is called a karyotype. To create one, scientists take an image of the stained chromosomes and identify...

replication in prokaryotes

How Prokaryotic DNA Is Copied

Prokaryotic DNA is copied through a coordinated process with three main stages: initiation, elongation, and termination. It begins when initiator proteins bind to the single origin of replication, or ori, on the cell’s circular chromosome. The DNA then copies around the circle in both directions, starting from two replication forks, and this produces two DNA molecules. Several proteins work together to open and protect the DNA during replication. Topoisomerase cuts one side of the...

replication in eukaryotes

Eukaryotic DNA Copying and Telomeres

Eukaryotic DNA copying is tightly regulated and must duplicate many linear chromosomes before cell division. The process is highly conserved and uses many proteins with specialized roles. It moves through initiation, elongation, and termination, and it ends with two complete sets of chromosomes in the nucleus. Eukaryotic replication shares basic steps with prokaryotic DNA replication, but the larger genome and linear chromosomes require more proteins. Replication begins at multiple origins of...

proofreading

DNA Polymerase Fixes Replication Errors

DNA polymerase helps copy DNA and fix mistakes during replication. It adds nucleotides in a sequence that matches the template DNA strand. The enzyme also has a higher affinity for the correct base, which helps keep DNA replication accurate. As new genomic DNA is made, it is synthesized in the 5’ to 3’ direction. In many cells, DNA polymerases have different jobs in this process. DNA polymerase delta and DNA polymerase epsilon can proofread when nuclear DNA is being copied. These polymerases...

mismatch repair

DNA Mismatch Repair in Replication

DNA mismatch repair fixes copying errors that happen during DNA replication. When DNA polymerase makes a mistake, the cell can detect a wrong base pair, such as A with G or T with C, and replace it with the correct nucleotide. This repair system works in both prokaryotes and eukaryotes and depends on several proteins. The Mutator protein family plays a central role in this process. In bacteria such as Escherichia coli, MutS first binds the mismatch. MutL then helps identify which strand is the...

nucleotide excision repair

DNA Damage Repair by Excision

DNA damage repair by excision protects cells from mutagens that can change DNA. Exposure to environmental mutagens can create bulky lesions that bend the double helix or block transcription. If these changes are not repaired, they can lead to mutations and may contribute to cancer or disease, depending on which DNA sequences are affected. Nucleotide excision repair, or NER, is the process that detects and removes this kind of damage. Specialized proteins scan the DNA for a damaged region, then...

mutations

DNA Changes From Point Mutations to UV Damage

Mutations are changes in the DNA sequence. They can happen by chance during DNA copying, or they can be caused by environmental factors such as radiation and chemicals. Scientists also describe mutations by how much DNA they affect, how they change a protein, and whether they happen in body cells or germline cells. Some mutations affect only one nucleotide, which is a point mutation. When a point mutation falls inside a gene, the outcome depends on how the amino acid sequence changes. A silent...

transcription

Transcription and Gene Control

Transcription and gene control explain how cells make RNA from DNA and decide which genes are active. RNA polymerase copies a DNA sequence into RNA, and this is the first step in making a protein from a gene. Many other proteins and control sequences help make messenger RNA, or mRNA, correctly. In eukaryotes, the DNA is first copied into a primary RNA, also called pre-mRNA. This RNA can then be processed into mature mRNA, which serves as the template for protein synthesis. In prokaryotes such...

translation

Protein Synthesis and mRNA Decoding

Protein synthesis begins when ribosomes decode messenger RNA (mRNA) and build a chain of amino acids. This final step of gene expression is called translation. The finished chain is a polypeptide, which can later become a functional protein. Proteins are often called the building blocks of life because they make up much of the body, from muscle fibers to hairs and immune system parts. The instructions for each protein are encoded in genes found in the DNA of every cell. In biology, the central...

bacterial transformation

Griffith’s Mouse Experiment and DNA

Bacterial transformation explains how DNA can move into bacteria and change their traits. Frederick Griffith first noticed this in 1928 while studying pneumonia-causing Streptococcus pneumoniae in mice. He compared one pathogenic strain with one non-pathogenic strain and found that only the pathogenic strain killed the host mice. Griffith made an unexpected discovery when he killed the pathogenic bacteria and mixed their remains with live, non-pathogenic bacteria. The mixture killed the mice,...

key terms and concepts

Explore how eukaryotic genes are organized with exons, introns, intergenic regions, and regulatory DNA, plus how splicing and alternative splicing work.

Genes, Introns, and Regulatory DNA | JoVE K12

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What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (&#x3BC;m)and are considerably smaller than most ...

Eukaryotic Compartmentalization

One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry ...

Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains&#x2014;Archaea and Bacteria. Bacteria include many common organisms, such as ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

Endoplasmic Reticulum

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration&#x2014;the ...

Introduction to the Cytoskeleton

Overview of the Cytoskeleton
The cytoskeleton is a network of protein filaments present within the cell, having three distinct filaments ...

Introduction to Actin

Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle ...

overview-of-myosin-structure-and-function

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with ...

Microtubules

Microtubules are the thickest cytoskeletal filaments with a diameter of 25 nm. In prokaryotic organisms, microtubules are commonly found in locomotory ...

The Structure of Intermediate Filaments

The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of ...

Types of Intermediate Filaments

The intermediate filaments are an essential component of the cytoskeleton. Presently six types of intermediate filament have been identified. Type I and ...

Gap Junctions

Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between ...

The Extracellular Matrix

In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, ...

Tissues

Cells with similar structure and function are grouped into tissues. A group of tissues with a specialized function is called an organ. There are four main ...

Plant Cell Wall

The plant cell wall gives plant cells shape, support, and protection. As a cell matures, its cell wall specializes according to the cell type. For ...

Plasmodesmata

The organs in a multicellular organism&#x2019;s body are made up of tissues formed by cells. To work together cohesively, cells must communicate. One way ...

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the ...

Binary Fission

Fission is the division of a single entity into two or more parts, which regenerate into separate entities that resemble the original. Organisms in the ...

Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

The DNA Helix

Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA as a Genetic Template

Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

Chromosome Structure

A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA ...

The Central Dogma

The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
RNA is the Missing Link Between ...

Mutations

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations ...

Proteins: From Genes to Degradation

Students who demonstrate understanding can construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.  Assessment Boundary: Assessment does not include the identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

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Levels of Organization

Biological organization is the classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth&#x27;s biosphere. ...

Taxonomy

Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics. It uses a hierarchy of increasingly ...

Phylogeny

Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon ...

Students who demonstrate understanding can develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.  Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction levels.

3.1.9-12.B

Functions of Life

Human life is characterized by a variety of functions that are essential for survival and well-being. These functions include metabolism, movement, ...

Requirements for Human Life

The Earth and its atmosphere have provided humans with air, water, and food, but these are not the only requirements for survival. Humans also require a ...

What is Homeostasis?

Maintaining homeostasis requires that the body continuously maintain its internal conditions. Each physiological condition has a particular set point, ...

Negative and Positive Feedback

Homeostatic Imbalance

Homeostasis is the maintenance of a stable internal environment within the body, which is crucial for the proper functioning of cells, tissues, organs, ...

Students who demonstrate understanding can plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.  Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.

3.1.9-12.C

Genes, Introns, and Regulatory DNA

Description

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