RNA and Protein RNA and Protein SynthesisSynthesisChapter 13Chapter 13

Why do we need RNA?Why do we need RNA?

DNA cannot leave the nucleusDNA cannot leave the nucleus DNA gets transcribe into Messenger DNA gets transcribe into Messenger

RNA (mRNA)RNA (mRNA) Once edited, mRNA can leave the Once edited, mRNA can leave the

nucleus as a single strandnucleus as a single strand

Similarities and Similarities and differences between DNA differences between DNA

and RNAand RNA http://www.usask.ca/education/coursewor

k/mcvittiej/bio30unit1/overheads/1.23.htm

Similarities and differences between DNA and Similarities and differences between DNA and RNARNA

Conection between DNA Conection between DNA and Proteinand Protein

DNA defines the genotype (genetic DNA defines the genotype (genetic makeup)makeup)

Proteins determine the phenotype Proteins determine the phenotype (specific trait)(specific trait)

Each gene codes for one protein Each gene codes for one protein (polypeptide)(polypeptide)

http://www.pbs.org/wgbh/nova/body/rnai.html

DNA to Protein DNA to Protein ConnectionConnection Geneticists Beadle and Tatum studied Geneticists Beadle and Tatum studied

mutant strain of orange moldmutant strain of orange mold This strain was missing a necessary This strain was missing a necessary

enzyme for mold to growenzyme for mold to grow Each mutant strain was defective in a Each mutant strain was defective in a

single genesingle gene One gene-on enzyme hypothesisOne gene-on enzyme hypothesis More accurate – One gene one polypeptide More accurate – One gene one polypeptide

http://www.youtube.com/watch?v=vIrrtM47Wio9:33

Life is orchestrated by Life is orchestrated by ProteinsProteinsProteinsProteins Combinations of 20 Combinations of 20

different amino acids different amino acids linked in long chainslinked in long chains

Function is determined Function is determined by amino acid by amino acid sequencesequence

Amino acid sequence Amino acid sequence is determined by DNA is determined by DNA sequencesequence

Used for enzymes, Used for enzymes, hair, muscles, cell partshair, muscles, cell parts

Amino Acids LinkedAmino Acids Linked Amino Acids Link Together to Form Amino Acids Link Together to Form

a Protein (Polypeptide)a Protein (Polypeptide)

Protein SynthesisProtein Synthesis

DNA → RNA → Protein (polypeptide)DNA → RNA → Protein (polypeptide)

This happens in two main steps:This happens in two main steps:

Transcription Transcription RNA synthesisRNA synthesisRNA editingRNA editing

TranslationTranslation

Transcription-translation Transcription-translation animationsanimations

http://www.hhmi.org/biointeractive/dna/animations.html

http://www.youtube.com/watch?v=YxLdBNAxqKg&src_vid=T1DV-tDaKEo&feature=iv&annotation_id=annotation_561613

http://www.youtube.com/watch?v=T1DV-tDaKEo

http://www.youtube.com/watch?v=1fiJupfbSpg

Information is sent from the Information is sent from the Nucleus to ribosome where protein Nucleus to ribosome where protein is madeis made

Outline of making ProteinOutline of making Protein Directions on DNADirections on DNA DNA opens up and messenger RNA (mRNA) copies DNA opens up and messenger RNA (mRNA) copies

messagemessage mRNA is edited – some parts taken out (introns)mRNA is edited – some parts taken out (introns) mRNA goes out of nucleus to ribosomemRNA goes out of nucleus to ribosome mRNA attaches to ribosomemRNA attaches to ribosome Transfer RNA (tRNA) picks up an amino acid Transfer RNA (tRNA) picks up an amino acid tRNA attaches to mRNA matching complementary base tRNA attaches to mRNA matching complementary base

pairs at opposite end from amino acidpairs at opposite end from amino acid Amino acid is attached to other amino acids held by the Amino acid is attached to other amino acids held by the

ribosome to make a chain of proteinribosome to make a chain of protein When protein completely built unattached from ribosomeWhen protein completely built unattached from ribosome

1. A sequence of nucleotidesIn DNA (a gene) is transcribed to RNA in the nucleus

2. The RNA travels to the cytoplasm where it is translated into the specific amino acid sequece of a polypeptid

A codon is a three-base "word" that codes for one amino acid.

Several codons form a "sentence" that translates into a polypeptide.

Transcription playersTranscription players

DNADNA Messenger RNA (mRNA)Messenger RNA (mRNA) RNA polymeraseRNA polymerase

TranscriptionTranscription

mRNA editingmRNA editing

Translation playersTranslation players

mRNAmRNA Transfer RNATransfer RNA RibosomeRibosome Ribosomal RNARibosomal RNA

TranslationTranslation

Transcription-translation Transcription-translation animationsanimations

http://www.hhmi.org/biointeractive/dna/animations.html

http://www.youtube.com/watch?http://www.youtube.com/watch?v=YxLdBNAxqKg&src_vid=T1DV-v=YxLdBNAxqKg&src_vid=T1DV-tDaKEo&feature=iv&annotation_id=annotatiotDaKEo&feature=iv&annotation_id=annotation_561613n_561613

http://www.youtube.com/watch?v=T1DV-http://www.youtube.com/watch?v=T1DV-tDaKEotDaKEo

http://www.youtube.com/watch?http://www.youtube.com/watch?v=1fiJupfbSpgv=1fiJupfbSpg

Protein making analogy short movieProtein making analogy short movie

http://www.pbs.org/wgbh/nova/sciencenow/3210/02.html

00:54 – 03:20

What are MutationsWhat are Mutations

Any Any changechange in the in the nucleotide sequence nucleotide sequence of DNAof DNA

Two types of Two types of point mutations point mutations (involving (involving only one or a few nucleotides)only one or a few nucleotides)

Base substitutionsBase substitutionsBase deletions or Base deletions or

insertionsinsertions

Types of mutationsTypes of mutations

Bill Nye Genetics greatest discoveriesBill Nye Genetics greatest discoveries http://www.youtube.com/watch?http://www.youtube.com/watch?

v=vIrrtM47Wiov=vIrrtM47Wio http://school.discoveryeducation.com/http://school.discoveryeducation.com/

teachersguides/pdf/lifescience/ds/teachersguides/pdf/lifescience/ds/greatest_discoveries_nye_genetics.pdfgreatest_discoveries_nye_genetics.pdf

From DNA to ProteinFrom DNA to Protein