PROTEIN SYNTHESIS copyright cmassengale1

Starting with DNA DNA is the molecule that stores genetic information in the nucleus.DNA is the molecule that stores genetic information in the nucleus. It is a “code” that builds the molecules of life (proteins).It is a “code” that builds the molecules of life (proteins). DNA stays in the nucleus, but molecules are built in the cytoplasm of the cell.DNA stays in the nucleus, but molecules are built in the cytoplasm of the cell. So, the code must be copied and moved out into the cytoplasm, where proteins are assembled.So, the code must be copied and moved out into the cytoplasm, where proteins are assembled. This process is called PROTEIN SYNTHESISThis process is called PROTEIN SYNTHESIS 2

3 Genes & Proteins  Proteins are made of amino acids linked together by peptide bonds  20 different amino acids  Amino acids chains are called polypeptides  Segment of DNA that codes for the amino acid sequence in a protein are called genes

RNA copyright cmassengale4

RNA (ribonucleic acid) The nucleic acid that carries the genetic information on DNA from the nucleus out to the cytoplasm, where proteins will be made. copyright cmassengale 5

RNA is similar to DNA 1. They both are made up of nucleotides 2. They both have a sugar 3. They both have 4 nitrogen bases 4. They both have a phosphate 6

RNA Differs from DNA DNA 1.DNA has a sugar deoxyribose 2.DNA contains the base thymine (T) 3.DNA molecule is double-stranded RNA 1.RNA has a sugar ribose 2.RNA has uracil (U) 3.RNA is single- stranded 7

Roles of RNA and DNA DNA is the MASTER PLAN RNA is the BLUEPRINT of the Master Plan copyright cmassengale8

Structure of RNA copyright cmassengale9

Types of RNA copyright cmassengale 10

3 KINDS OF RNA _________________RNA (mRNA) Copies the code from DNA and carries it out. _________________RNA (rRNA) With proteins, it forms ribosomes _________________RNA (tRNA) Matches mRNA to “transfer” the correct amino acids to make a protein. rRNA and t-RNA images from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved mRNA image from RIBOSOMAL TRANSFER MESSENGER

Remember… The purpose of DNA is to store and transmit the genetic code so that…… Proteins can be made. copyright cmassengale 12

Pathway to Making a Protein DNAmRNA tRNA (ribosomes) Protein copyright cmassengale14

Protein Synthesis   The process of making proteins from the code on DNA.  Two phases: 1. Transcription 2. Translation copyright cmassengale15

DNA  RNA  Protein copyright cmassengale16 Nuclear membrane Transcription RNA Processing Translation DNA Pre-mRNA mRNA Ribosome Protein Eukaryotic Cell

Transcription and Translation copyright cmassengale17

Transcription copyright cmassengale18

Transcription The process of copying one strand of DNA onto mRNA Follows the base pair rule. copyright cmassengale19

Template Strand copyright cmassengale20

21

22 What is the enzyme responsible for the production of the mRNA molecule?

23 RNA Polymerase  Enzyme found in the nucleus  Separates the two DNA strands by breaking the hydrogen bonds between the bases  Then moves along one of the DNA strands and links RNA nucleotides together

24 DNApre-mRNA RNA Polymerase

25 Question:  What would be the complementary RNA strand for the following DNA sequence? DNA 5’-GCGTATG-3’

26 Answer: DNA 5’-GCGTATG-3’DNA 5’-GCGTATG-3’ RNA 3’-CGCAUAC-5’RNA 3’-CGCAUAC-5’

You Practice! DNAAATCGG DNACATTAC DNAGCGATT copyright cmassengale27 RNA UUAGCC RNA GUAAUG RNA CGCUAA

mRNA Processing After the DNA is transcribed, the mRNA, is edited –The entire DNA strand is copied. –Introns (which don’t code for proteins) are cut out. –Exons (which do code for proteins) are spliced back together. copyright cmassengale28

Result of Transcription Introns are orange; Exons are green

mRNA Transcript copyright cmassengale30 mRNA leaves the nucleus and goes to the ribosomes

Messenger RNA (mRNA) ON the mRNA is a codon:ON the mRNA is a codon: a group of 3 nucleotides that will code for one amino acid. AUG – methionine or start codonAUG – methionine or start codon UAA, UAG, or UGA – stop codonsUAA, UAG, or UGA – stop codons GGC - GlycineGGC - Glycine copyright cmassengale31

The Genetic Code A codon designates an amino acid There are 20 amino acids, but 64 possible codons copyright cmassengale32

The Genetic Code copyright cmassengale33 Use the code by reading from the center to the outside Example: AUG codes for Methionine

Name the Amino Acids GGG? UCA? CAU? GCA? AAA? copyright cmassengale34

Review 1. What happens in transcription (step 1 of protein synthesis)? The code in DNA is copied onto an mRNA, in the nucleus. copyright cmassengale 35

Review #2 Once the mRNA is made, it leaves the nucleus and goes to a _____________. copyright cmassengale 36 ribosome

Review The mRNA is read by its “words”, which are called: _________, which are groups of 3 nucleotides. copyright cmassengale 37 codons

USE THE DNA CODE PROVIDED TO MAKE A COMPLEMENTARY RNA COPY U C G A G C C T G T A G G C A G A CA U CC G U Review #1

USE THE DNA CODE PROVIDED TO MAKE A COMPLEMENTARY RNA COPY A A G T T C A A G C A A T C G U U CG U UA G C Review #2

Translation copyright cmassengale40

Translation Translation is the process of using the mRNA’s code to build a protein mRNA tRNAprotein copyright cmassengale41

Remember the types of RNA? Transfer RNA (tRNA) 42 Messenger RNA (mRNA) 3 bases are called a: Codon Anticodon

Codons and Anticodons A codon is on mRNA. An anticodon is on the tRNA and is a complement to the codon. Example: Codon ACU Anticodon UGA copyright cmassengale43 UGA ACU

THE mRNA strands’ codons determine the complementary tRNA strands’ anticodons C U G A U G A A G C A U G A C U U C G U A U A C mRNA (Codons) tRNA (anticodons)

Name the anticodons to these codons: CCU UAG GUC AGU CUA copyright cmassengale45 GGA AUC CAG UCA GAU

Translation Steps 1. Anticodons on the tRNA match up with the codons on mRNA. 2. Each tRNA carries one amino acid. 3. The amino acids are joined to form proteins. (Happens in the ribosomes.) copyright cmassengale46

___________ on tRNA matches up with ________ on mRNA Images modified from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved ANTICODON CODON EACH tRNA carries only one kind of _____________ amino acid

Copyright Pearson Prentice Hall Translation

Copyright Pearson Prentice Hall Translation tRNA Ribosome mRNA Lysine Translation direction

Copyright Pearson Prentice Hall Translation Protein Ribosome tRNA mRNA

End Product –The Protein! A sequence of amino acids bonded together copyright cmassengale51 aa1 aa2 aa3 aa4 aa5 aa200 aa199

USE THE mRNA CODE PROVIDED TO ADD THE COMPLEMENTARY tRNA C U G A U G A A G C A U G A C U U C G U AU A C Anticodons #7

USE THE mRNA CODE PROVIDED TO ADD THE COMPLEMENTARY tRNA C U G A U G A A G C A U G A C U U C G U A U A C #8

USE THE mRNA CODE PROVIDED TO ADD THE COMPLEMENTARY tRNA C U G A U G A A G C A U G A C U U C G U A U A C #9

USE THE mRNA CODE PROVIDED TO ADD THE COMPLEMENTARY tRNA C U G A U G A A G C A U G A C U U CG U A #10

USE THE mRNA CODE PROVIDED TO ADD THE COMPLEMENTARY tRNA C U G A U G A A G C A U G A C G U A #11

USE THE CODON WHEEL TO TELL THE AMINO ACID SEQUENCE OF THE PROTEIN THIS mRNA WILL MAKE ALANINE - C A G G C A G C U U U U GLUTAMINE - PHENYLALANINE ALANINE - #12

USE THE CODON WHEEL TO TELL THE AMINO ACID SEQUENCE OF THE PROTEIN THIS mRNA WILL MAKE HISTIDINE - G U C A G C C A U U G A VALINE - STOP SERINE - #13

DNA → DNA ____________ DNA → RNA ____________ RNA → Protein ___________ REPLICATION TRANSCRIPTION TRANSLATION Closure Fill in the blanks with the correct process.

copyright cmassengale60