Unit 4 Inheritance of Traits Part 2 How

Unit 4 Inheritance of Traits Part 2: How DNA codes for Proteins

DNA carries the info to make Proteins. How does it work? DNA RNA Proteins Starts with DNA…. transcribed into m. RNA…. . translated into proteins by t. RNA This process is known as: Central Dogma of Molecular Biology How does the DNA get made into RNA and that made into Protein? ? ? .

Transcription When DNA inside the nucleus is TRANSCRIBED (re-written) Into m. RNA. This strand then leaves the nucleus.

DNA Deoxiribonucleic RNA Ribonucleic acid 1. sugar = ribose 1. sugar=deoxyribose 2. Bases=A, C, G, U 2. bases = A, C, G, T 3. single strand 3. double strand 4. leaves nucleus 4. stays in nucleus

What are three main differences between DNA and RNA?

12– 3 RNA and Protein Synthesis The Structure of RNA There are three main differences between RNA and DNA: • The sugar in RNA is ribose instead of deoxyribose. • RNA is a single-stranded polymer molecule • RNA contains the base: uracil, in place of thymine. Slide 6 of 39 Copyright Pearson Prentice Hall End Show

3 Types of RNA are made from DNA 1. m. RNA “messenger” made from DNA in nucleus…travels out of nucleus and finds a ribosome. 2. t. RNA “transfer” brings amino acids to the ribosomes; found in cytoplasm 3. r. RNA “ribosomal” part of the ribosome; this is where proteins are made

12– 3 RNA and Protein Synthesis Types of RNA Messenger RNA (m. RNA) carries copies of instructions for assembling amino acids into proteins. Slide 8 of 39 Copyright Pearson Prentice Hall End Show

12– 3 RNA and Protein Synthesis Types of RNA Ribosome Ribosomal RNA Ribosomes are found in all Eukaryotic and Prokaryotic organisnms and are made up of proteins and ribosomal RNA (r. RNA). Copyright Pearson Prentice Hall Slide 9 of 39 End Show

12– 3 RNA and Protein Synthesis Types of RNA Amino acid Amino Acids are monomers (subunits) of proteins Transfer RNA During protein construction, transfer RNA (t. RNA) transfers each amino acid to the ribosome. Slide 10 of 39 Copyright Pearson Prentice Hall End Show

Lets watch: TRANSCRIPTION l https: //www. youtube. com/watch? v=-Ans. JILjbz 8 l

Transcribe this…… Remember: Uracil (U) is used during transcribing, so do not use Thymine (T) | I | | | | |

Is ALL the DNA transcribed into m. RNA? l. NO!!! l Only certain sections of the DNA (GENES) are made (transcribed) into message (m. RNA)

Now…to make proteins from the m. RNA Translation l This is called: l Translation is the decoding of an m. RNA message into a an amino acid chain creating a (protein). l The m. RNA goes into the Ribosome and a t. RNA molecule brings amino acids.

Codon A grouping of 3 m. RNA bases l This tells the TRNA what amino Acid to bring l

12– 3 RNA and Protein Synthesis Translation The ribosome binds new t. RNA molecules and amino acids as it moves along the m. RNA. Phenylalanine t. RNA Lysine Methionine Ribosome m. RNA Start codon Copyright Pearson Prentice Hall Slide 17 of 39 End Show

Why do we need Proteins? 1. Proteins give certain traits and capabilities to organisms l Ex: lots of the protein melanin leads to darker pigment EX: Production of insulin helps in glucose metabolism 2. Proteins act as enzymes to make reactions go faster, act as parts of muscle, skin, bone, & organs!! 3. Proteins are hormones & cell signalers 4. Organisms are dependent on proteins in order to function! Copyright Pearson Prentice Hall

Translation : Decoding the Message FOR REVIEW 1. 2. 3. 4. 5. m. RNA leave nucleus and enters ribosome m. RNA codons read & t. RNA brings matching amino acid to the ribosome Amino acids are strung together like beads on a necklace Amino Acids are held together by peptide bonds 1000 or more Amino Acids = protein

TRANSLATION Lets watch! l https: //www. youtube. com/watch? v=5 b. LEDd-PSTQ l

12– 3 RNA and Protein Synthesis The Genetic Code Use the RNA Codon Chart to decode RNA into amino acids. The genetic code is the “language” of m. RNA instructions. The code is written using four “letters” (the bases: A, U, C, and G). Slide 21 of 39 Copyright Pearson Prentice Hall End Show

WHEN WE DECODE DNA ü ü Use the “Genetic Code” Convert m. RNA 3 letter groupings called codons Example: AUG= Methylamine (Start) ü The m. RNA Code tells us what amino acid each codon codes for.

12– 3 RNA and Protein Synthesis The Genetic Code Slide 23 of 39 Copyright Pearson Prentice Hall End Show

Translation 12– 3 RNA and Protein Synthesis Lysine t. RNA Translation direction m. RNA Ribosome Copyright Pearson Prentice Hall Slide 25 of 39 End Show

12– 3 RNA and Protein Synthesis Translation The process continues until the ribosome reaches a stop codon. Polypeptide Ribosome t. RNA m. RNA Copyright Pearson Prentice Hall Slide 26 of 39 End Show

REVIEW! Watch these: l https: //www. youtube. com/watch? v=g. G 7 u. Csk. UOr. A l https: //www. youtube. com/watch? v=28 mgfg 8 n. RT 4 l

Transcribe and Translate this DNA Strand without looking at your notes TACAGTACCATAATC NOW, Label the DNA, m. RNA, amino acid, Which part is transcription Which is translation ?

TACAGTACCATAATC m. RNA AUGUCAUGGUAUUAG DNA AA: MET-SER-TRP-TYR-STOP Codon Amino Acid