DNA, RNA Structure and Function PDF

DNA, RNA BY Dr/ Eman Elsaid Khalifa Lecturer of cellular and molecular biology Nile valley University  Overview Chromatin is the complex of DNA and protein (Histone) that comprise eukaryotic chromosomes. The primary function of chromatin is to compre...

DNA, RNA BY Dr/ Eman Elsaid Khalifa Lecturer of cellular and molecular biology Nile valley University  Overview Chromatin is the complex of DNA and protein (Histone) that comprise eukaryotic chromosomes. The primary function of chromatin is to compress the DNA into a compact unit that will be less volume and can fit within the nucleus.  What is DNA? DNA is a nucleic acid DNA stands for Deoxyribonucleic Acid DNA – is the genetic material inside the nucleus of eukaryotic cells.  Deoxyribonucleic Acid Segment of DNA NUCLEUS GENES SEGMENTS CHROMOSOMES OF DNA What is the purpose, or function, of DNA? Stores the genetic information that instructs the cell on which proteins to make. So, DNA makes PROTEINS (both are biomolecules!) Responsible for determining all organism’s traits such as eye color, body structure, and enzyme production. Proteins are responsible for most of these traits!  The Components of DNA DNA is a long molecule made up of repeating individual units called nucleotides. Nucleotides are made up of three parts that are held together by covalent bonds: 1. Sugar 2. Phosphate Group 3. Nitrogenous Base Nitrogenous Bases DNA contains four nitrogenous bases: 1. Adenine (A) 2. Guanine (G) 3. Cytosine (C) 4. Thymine (T) In DNA, Which Bases Pair? Adenine (A) always pairs with Thymine (T) Guanine (G) always pairs with Cytosine (C) Covalent bonds  DNA is a DOUBLE HELIX or a twisted ladder. Ribonucleic Acid (RNA) RNA is SINGLE STRANDED and does not have to stay in the nucleus. RNA is not found in chromosomes because it does not carry the genetic code, however it can read the DNA code and take the information out of the  RNA Structure The building blocks of RNA are Nucleotides, just like DNA. A Nucleotide in RNA is still made of 3 important things: 1. 6-Carbon Sugar - Ribose (instead of Deoxyribose) 2. Phosphate 3. Nitrogen base there are 4 nitrogen bases in RNA, A,G,C, and U that pair together) AU CG  Types of RNA 1. Messenger RNA (mRNA) - Carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell (serve as “messenger”)  Types of RNA 2.Ribosomal RNA (rRNA) – Makes up the major part of ribosomes, which is where proteins are made. Ribosomal RNA  Types of RNA 3. Transfer RNA (tRNA) - Transfers amino acids to ribosomes during protein synthesis DNA vs. RNA STRUCTURE AND FUNCTION DNA RNA  Name DeoxyriboNucleic Acid (DNA) RiboNucleic Acid (RNA) Function Long-term storage of genetic information. Used to transfer the genetic code from the nucleus to the ribosomes to make proteins. Structural Double – stranded helix. RNA is a single-strand helix. Features Composition deoxyribose sugar ribose sugar of Bases and phosphate backbone phosphate backbone Sugars adenine, guanine, cytosine, thymine bases adenine, guanine, cytosine, uracil bases Propagation DNA is self-replicating. RNA is synthesized from DNA on a needed basis. Reactivity The C-H bonds in DNA make it fairly stable, plus the The O-H bond in the ribose of RNA makes the body destroys enzymes that would attack DNA. The molecule more reactive, compared with DNA. RNA is small grooves in the helix also serve as protection, not stable under alkaline conditions, plus the large providing minimal space for enzymes to attach. grooves in the molecule make it susceptible to enzyme attack. RNA is constantly produced, used, degraded, and recycled. Ultraviolet DNA is susceptible to UV damage. RNA is relatively resistant to UV damage. Damage