DNA & RNA SBI 3U
Feb 22, 2016
DNA & RNA
SBI 3U
Two types of Nucleic Acids
• DNA – Deoxyribonucleic Acid (double strand) 4 Bases Adenine, Thymine, Cytosine, Guanine
• RNA - Ribonucleic acid (single strand) 4 Bases Adenine, Uracil (replaces Thymine) Cytosine, Guanine
How DNA works
• The double helix unzips and reveals a section of genetic code.
• http://www.youtube.com/watch?v=hfZ8o9D1tus&feature=related
• http://www.youtube.com/watch?v=z685FFqmrpo&feature=related
Types of RNA• mRNA – messenger RNA Enters the nucleus
through the nuclear pores and “reads” the unzipped portion of the DNA strand.
tRNA – transfer RNA “reads” the mRNA strand in groups of 3 CODONS. Collects correct Amino Acid from the cell cytoplasm and adds this to the developing strand of amino acids.
Abbreviation
Name Function Structure
mRNA messenger RNA
it functions as a blueprint; it’s a code for
a single protein (or polypeptide chain)
single-stranded,
tRNA transport RNA
the translator, capable of reading the mRNA language and binding corresponding amino
acid to a growing peptide chain
cloverleaf
rRNA ribosomal RNA
the factory, an "enzyme" of sorts
complexed with
proteins
DNA strand unzips.
T A C T T C A A A A A C C G A C C G A T A
mRNA strand
mRNA leaves nucleus returns to Endoplasmic Reticulum . Links to Ribosomes.
tRNA collects amino acids and links them onto the developing protein
Where is DNA found?
• Nucleus of Eukarotic cells• DNA strand in Prokaryotic cells
mRNA
DNA T T C A T A G C C A G
A A G U A U C G G U C
mRNA = AAG –UAU- CGC - UC
CODONS
• Genetic Words• Start = AUG (Met) Like the capital letter of a
sentence.• Stop = UGA, UAA, UAG – like the period at the
end of a sentence.
Mutations
• Thesunwashotbuttheoldmandidnotgethishat.• The sun was hot but the old man did not get
his hat.FRAME SHIFT.• T hes unw ash otb utt heo ldm and idn otg
eth ish at.• Th esu nwa sho tbu tth eol dma ndi dno tge
thi sha t.
Genetic Diseases
The sickle cell mutation. One amino acid out of a total 287 differs in sickle cell haemoglobin compared with normal haemoglobin. In the latter, the triplet GAG (guanine, adenine, guanine) codes for the amino acid glutamic acid (left-hand diagram).
Genes
• A gene is a sentence that tells a cell how to make a protein. Any changes to the instructions can alter the gene’s meaning. There are different ways that these changes can occur.
Point Mutation: OriginalThe fat cat ate the wee rat.Point MutationThe fat hat ate the wee rat.Frame-shift mutation:OriginalThe fat cat ate the wee rat.Frame ShiftThe fat caa tet hew eer at.
Deletion: OriginalThe fat cat ate the wee rat.DeletionThe fat ate the wee rat.Insertion: OriginalThe fat cat ate the wee rat.InsertionThe fat cat xlw ate the wee rat.
Inversion:OriginalThe fat cat ate the wee rat.InsertionThe fat tar eew eht eta tac.