Take out your HW Transcription wkst Homework due

Take out your HW: Transcription wkst Homework due tomorrow: Protein Synthesis wkst Somewhere on a sheet of scratch paper or in your notes, TRANSCRIBE the following DNA sequence into m. RNA: TAC AGT CCA GCG ATA ATT AUG UCA GGU CGC UAU UAA

TRANSCRIPTION & TRANSLATION: From Chapter 11, Section 2 DNA to Protein Think back to the information contained in your homework assignment: 1. What is produced when the process of transcription is complete? 2. What are 2 differences that were listed/shown between DNA and RNA?

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) – Occurs through the processes of transcription and translation

RNA • RNA is a nucleic acid (like DNA) • Differs in structure from DNA: DNA RNA Number of Strands 2 1 Nucleotide Sugar Deoxyribose Ribose Nitrogenous Base Pairs Thymine(T), Adenine(A), Guanine (G), Cytosine (C) Uracil (U), Adenine(A), Guanine (G), Cytosine (C)

Focusing on RNA • There are 3 different types of RNA that you will need to know: – m. RNA – r. RNA – t. RNA

Types of RNA • 1. Messenger RNA (m. RNA) – Carries genetic “message” from DNA to the ribosomes in the cytosol – “Read” by ribosomes to make proteins – Contain codons

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

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

Transcription: Getting the message out of the nucleus • 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? • UUAGGCCU • The m. RNA that gets sequenced is sent out of the nucleus to help make protein

Genetic Code • Sequence of Nitrogenous Bases codes for a specific Amino Acid that is connected to other amino acids to make a Protein • Codon = the nitrogenous bases of 3 adjacent nucleotides in m. RNA that code for – Start Signal (starts the protein making process) – 1 of 20 different amino acids (parts of a protein) – Stop Signal (stops the protein making process) • Codons are like 3 -letter words – Words contain meaning to us: CAT = – Codons contain meaning in the form of an amino acid CAU = Histidine

• An amino acid can be coded for by more than one codon • 20 amino acids combine in different combinations to make various proteins

Translation: Going from the language of bases (AUGC) to proteins • Translation = using the m. RNA to make protein, reading the codons – Takes place at the ribosomes • The m. RNA is “read” in between the 2 sub-units of the ribosome • t. RNA carries the amino acid coded for by the m. RNA codons and has an anticodon that pairs up with the m. RNA codon – Codon (m. RNA) and anticodon (t. RNA) follow RNA base-pairing rules • Amino acids form peptide bonds between each other to create a long chain of amino acids

Transcription

Amino acids to protein • Amino acid chains start to fold creating 3 -dimensional structures • Several of these 3 D structures combine to form a functional protein • These proteins then carry out cellular functions