Protein Synthesis

Essential Questions:EQ: How does the cell make protein?EQ: Why do you need DNA and RNA?EQ: What do proteins have to do with the genetic traits?

Georgia Performance Standards:• Compare and contrast the structure and function of DNA and RNA• Explain the role of DNA in storing and transmitting cellular information

Essential Review

1. What are the four macromolecules organisms are made of?

2. Which one is used mostly for structure?

3. What is the monomer (-o-) of this macromolecule ( o-o-o-o) ?

Nucleic Acid Review• DNA: Deoxyribonucleic Acid• Double Helix• Found in:

– Nucleus (eukaryote)– Cytoplasm (prokaryote)

Composed of Nucleotides:• Deoxyribose Sugar• Phosphate group• Nitrogenous bases

– Adenine and Thymine– Cytosine and Guanine

Nucleic Acid Review• RNA: Ribonucleic

Acid• Single stranded• In cytoplasm

Types of RNA• mRNA (codon)• tRNA (anticodon)• rRNA

Nucleotide:• Ribose sugar• Phosphate

group• Nitrogen base

– Adenine – Uracil– Cytosine– Guanine

12.3 DNA, RNA, and Protein

Molecular Genetics

DNA RNA Protein DNA can NOT leave the

nucleus. “Big Boss”

So, how does the info from DNA get to the cytoplasm (ribosome)?

Molecular Genetics

12.3 DNA, RNA, and Protein

Chapter 12

CODON [ ] Anticodon

from to to make up

Concept MapSection 12-3

also called which functions to also called also called which functions towhich functions to

can be

RNA

Messenger RNA Ribosomal RNA Transfer RNA

mRNA (Codon)

Carry instructions rRNACombine

with proteinstRNA

(anticodon)

Bringamino acids to

ribosome

DNA Ribosome Ribosomes

Go to Section:

DNA is unzipped in the nucleus and RNA

polymerase binds to a specific section where an mRNA will be synthesized.

Molecular Genetics

Transcription

Through transcription, the DNA code is transferred to mRNA in the nucleus.

12.3 DNA, RNA, and Protein

Chapter 12

Molecular Genetics

The Code

Experiments during the 1960s demonstrated that the DNA code was a three-base code.

The three-base code in DNA or mRNA is called a codon.

12.3 DNA, RNA, and Protein

Chapter 12

Molecular Genetics

Translation In translation, tRNA

molecules act as the interpreters of the mRNA codon sequence.

At the middle of the folded strand, there is a three-base coding sequence called the anticodon.

Each anticodon is complementary to a codon on the mRNA.

12.3 DNA, RNA, and Protein

Chapter 12

Molecular Genetics12.3 DNA, RNA, and Protein

Chapter 12

Protein Synthesis Overview:

• Genes are sequences of DNA that code for the production of proteins in the cell.

– mRNA (codon) enters the nucleus

– RNA polymerase copies part of the nucleotide sequence from DNA into RNA (transcription)

• DNA: CCC-TAG-GAT-GTA-CGC

• mRNA: GGG-AUC-CUA-CAU-GCG

• Video Clip- 4 min. MyContent

Protein Synthesis Overview:

– mRNA goes through the nuclear pores to take that copy to the ribosome, which is in the cytoplasm.

– tRNA (anticodon) reads the mRNA (codon) and transfers amino acids to make proteins (translation)

• mRNA: GGG-AUC-CUA-CAU-GCG

• tRNA: CCC-UAG-GAU-GUA-CGC

• Glyine-Isoleusine-Leucine-Histidine-Alanine

• Video Clip

Elongation:

• The ribosome joins amino acids together through peptide bonds.

• The ribosome moves along the mRNA binding new tRNA and amino acid molecules.

Termination:

• The process continues until the ribosome reaches one of the three stop codons.– UGA– UAG– UAA

The Genetic Code:

• Because there are four different bases, there are 64 possible three-base codons (4 × 4 × 4 = 64).

• Some amino acids can be specified by more than one codon.

• For example, six different codons specify the amino acid leucine, and six others specify arginine.

 The Genetic Code

Check for Understanding:

1. List the three main types of RNA. 2. What happens during transcription?3. What happens during translation? 4. Describe the three main differences

between RNA and DNA. 5. Using the genetic code, identify the

amino acids that have the following messenger RNA strand codes: UGGCAGUGC.

Protein Synthesis

Essential Questions:EQ: How does the cell make protein?EQ: Why do you need DNA and RNA?EQ: What do proteins have to do with the genetic traits?

Georgia Performance Standards:• Compare and contrast the structure and function of DNA and RNA• Explain the role of DNA in storing and transmitting cellular information

Warm-up (Choose one):

• Choice 1: Venn diagram – Compare and

contrast DNA and RNA.

– Indicate location, structure, & function

• Choice 2: Descriptive Writing

• An RNA molecule is looking for a job in a protein synthesis factory, and it asks you to write its résumé.

• This RNA molecule is not yet specialized and could, with some structural changes, function as either mRNA, tRNA, or rRNA.

• The résumé you create should reflect the qualifications needed for each type of RNA.

Formative Assessment Review

• Below, you are given a DNA sequence. Transcribe the correct mRNA (codon) sequence. Use the genetic code to determine the correct tRNA (anticodon) sequence. Translate the correct amino acid sequence from the mRNA codon.

• Hints: DNA (A-T and G-C)RNA (A-U and G-C) • The codon codes for the amino acid sequence

DNA = GGG-ATC-CTA-CAT-GCGmRNA (codon) = tRNA (anticodon) = Amino Acids =

RIBOSOME GAMEDNA =CTA-CTG-GTG-CTT-CTC-CGA-CGG-CGT-TTA-TTT-

CCC-GCG-GTG-CTT

mRNA = GAU-GAC-CAC-GAA-GAG-GCU-GCC-GCA-AAU-AAA-GGG-CGC-CAC-GAA

tRNA =CUA-CUG-CUC-CUU-CUC-CGA-CGG-CGU-UUA-UUU-CCC-GCG-GUG-CUU

AMINO ACIDS= ASP-ASP-HIS-GLU-GLN-GLU-ALA-ALA-ASN-LYS-GLY-ARG-HIS-GLU

Word Wall: • Protein• DNA

polymerase• RNA

polymerase• Plasmid• Chromosome• mRNA• tRNA• rRNA • Promoter• Initiation• Avery• Hershey &

Chase• Prokaryote• Eukaryote

• Deoxyribose sugar• Adenine• Guanine• Thymine• Cytosine• Uracil• Gene• Chargoff• Single stranded• Cytoplasm• Nucleus• Double helix • Termination• Griffith• Ribose Sugar

•Watson & Crick•Rosalind Franklin•Transformation•Base pairing•Nucleotide•Chromatin•Histone•Replication•Transcription•Translation•Codon•Anticodon•Phosphate •Elongation