Regents Biology

Learning Objectives1. How is the code of DNA translated into

messenger RNA?

2. How is messenger RNA transcribed into a protein?

3. Describe how to make a protein (beginning with a gene).

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Bodies are made up of cells

All cells run on a set of instructions spelled out in DNA

Bodies → Cells → DNA

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How does DNA code for cells & bodies? how are cells and bodies made from the

instructions in DNA

DNA → Cells → Bodies

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DNA has the information to build proteins genes

DNA → Proteins → Cells → Bodies

proteinscells

bodiesDNA gets all the glory,Proteins do all the work

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How do proteins do all the work Proteins

proteins run living organisms enzymes

control all chemical reactions in living organisms

structure all living organisms are built out of proteins

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cytoplasm

nucleus

Cell organization DNA

DNA is in the nucleus genes = instructions for making proteins

want to keep it there = protected “locked in the vault”

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Cell organization Proteins

chains of amino acids made by a “protein factory” in cytoplasm protein factory = ribosome

nucleus

cytoplasm

ribosome

buildproteins

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Passing on DNA information Need to get DNA gene information

from nucleus to cytoplasm need a copy of DNA messenger RNA

nucleus

cytoplasm

ribosome

mRNA

buildproteins

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mRNA

From nucleus to cytoplasm

DNA

transcription

nucleus cytoplasm

translation

trait

protein

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DNA vs. RNADNA

deoxyribose sugar nitrogen bases

G, C, A, T T : A C : G

double stranded

RNA ribose sugar nitrogen bases

G, C, A, U U : A C : G

single stranded

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Transcription Making mRNA from DNA

DNA strand is the template (pattern) match bases

U : A G : C

Enzyme RNA polymerase

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Matching bases of DNA & RNA Double stranded DNA unzips

A G GGGGGT T A C A C T T T T TC C C CA A

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Matching bases of DNA & RNA Double stranded DNA unzips

A G GGGGGT T A C A C T T T T TC C C CA A

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Matching bases of DNA & RNA Match RNA bases to DNA

bases on one of the DNA strands

U

A G GGGGGT T A C A C T T T T TC C C CA A

U

UU

U

U

G

G

A

A

A C CRNA

polymerase

C

C

C

C

C

G

G

G

G

A

A

A

AA

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Matching bases of DNA & RNA U instead of T is matched to A

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

U C CCCCCA A U G U G A A A A AG G G GU Uribosome

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protein

cytoplasm

nucleus

traitU C CCCCCA A U G U G A A A A AG G G GU U

ribosome

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How does mRNA code for proteins mRNA leaves nucleus

mRNA goes to ribosomes in cytoplasm

Proteins built from instructions on mRNA

aa aa aa aa aa aa aa aa

How?

mRNA

U C CCCCCA A U G U G A A A A AG G G GU U

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How does mRNA code for proteins?

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

Met Arg Val Asn Ala Cys Alaprotein

?

How can you code for 20 amino acids withonly 4 DNA bases (A,U,G,C)?

ribosome

aa aa aa aa aa aa aa aa

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AUGCGUGUAAAUGCAUGCGCCmRNA

mRNA codes for proteins in triplets

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

Met Arg Val Asn Ala Cys Alaprotein

?

Codon = block of 3 mRNA bases

codon

ribosome

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For ALL life! strongest support

for a common origin for all life

Code has duplicates several codons for

each amino acid mutation insurance!

Start codon AUG methionine

Stop codons UGA, UAA, UAG

The mRNA code

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How are the codons matched to amino acids?

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

anti-codon

codon

tRNAUAC

MetGCA

ArgCAU

Val Anti-codon = block of 3 tRNA bases

aminoacid

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mRNA to protein = Translation The working instructions → mRNA The reader → ribosome The transporter → transfer RNA (tRNA)

mRNAU C CCCCCA A U G U G A A A A AG G G GU U

aaaa

aa

tRNA

GGU

aa

tRNA

U A C

aa

tRNA

GA C

tRNA

aa

A GU

ribosome

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aa

aa

aaaa

aa

aa

aa

mRNA

From gene to protein

DNA

transcription

nucleus cytoplasm

protein

translation

trait

U C CCCCCA A U G U G A A A A AG G G GU Uribosome

tRNA

aa

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protein

transcription

cytoplasm

nucleus

translation

trait

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From gene to protein

transcriptiontranscription

translationtranslation

proteinprotein

Regents Biology

Cut to the video… http://www.youtube.com/watch?v=h3b9ArupXZg

Regents Biology 2009-2010

Whoops!See what happens when

your genes don’t work right!

Any Questions??