TRANSCRIPTION & TRANSLATION: From DNA to Protein Chapter 11, Section 2

Site explains Transcription and Translation Also talks about other Genetics Concepts

Genes & Proteins What is the function of a gene? codes for traits, inherited from parents Genes code for specific proteins Proteins make up muscles, hair, tissues, enzymes, & pigments Protein Synthesis = reading the DNA, forming RNA, using RNA to make the protein (DNA  RNA  Protein) Replication DNA  DNA Transcription DNA  RNA Translation RNA  Amino Acids

RNA RNA is a nucleic acid (like DNA) Differs in structure from DNA: DNARNA Number of Strands21 Nucleotide SugarDeoxyriboseRibose Nitrogenous Base Pairs Thymine(T), Adenine(A), Guanine (G), Cytosine (C) Uracil (U), Adenine(A), Guanine (G), Cytosine (C)

Types of RNA – mRNA, rRNA, tRNA 1. Messenger RNA (mRNA) –Single strand –Transfers info from the gene (made of DNA inside the nucleus) to make a protein –mRNA carries genetic “message” from DNA to the ribosomes in the cytosol

2. Ribosomal RNA (rRNA) –Part of the structure of ribosomes –Ribosome = protein and rRNA

3. Transfer RNA Transfers amino acids to the ribosome to make protein

Transcription – DNA  mRNA Transcription = enzymes make RNA by copying a portion of DNA in the nucleus If a DNA sequence is AATCCGGA, what is the complimentary RNA sequence? (Remember RNA doesn’t have Thymine, it has Uracil instead) UUAGGCCU The mRNA that gets sequenced is sent out of the nucleus to help make protein

Genetic Code A certain sequence of Nitrogenous Bases codes for a specific Amino Acid needed to make a Protein Codon (on mRNA) = the nitrogenous bases of 3 adjacent nucleotides in mRNA that code for –Start Signal (starts the protein making process) –Stop Signal (stops the protein making process) –Amino Acid An amino acid can be coded for by more than one codon 20 amino acids combine in different combinations to make various proteins

Translation – mRNA  protein Translation = using the mRNA to make protein, reading the codons Translation takes place at the ribosomes which attach to the mRNA tRNA is the carrier that comes in bringing the amino acid coded for by the mRNA codons tRNA has an anticodon that pairs up with the mRNA codon If an mRNA codon is UUG, what is the matching tRNA anticodon? AAC As the amino acids are brought in peptide bonds form between them to link them in a chain

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