RNA and Protein Synthesis

How does DNA determine our traits?

How does DNA determine our traits?

• By directing the synthesis of proteins• Proteins represent functional genes• Molecular flow of information is:

DNA RNA Protein

What proteins are you familiar with?

Examples of Proteins

• Insulin• Keratin• Hemoglobin• Melanin• Actin

Proteins are synthesized during two cellular processes.

Can you name these processes?

Protein Synthesis

1. Transcription – Genetic information is transferred from DNA to RNA

2. Translation – mRNA information is decoded to synthesize proteins

What is RNA?

What is RNA?

• A nucleic acid composed of ribose sugars, phosphates, and nitrogenous bases

How does RNA differ from DNA?

DNA RNA

• Double stranded

• Deoxyribose sugar

• Adenine, Cytosine, Guanine, and Thymine

• Nucleus only

• Single stranded

• Ribose sugar

• Adenine, Cytosine, Guanine and Uracil

• Nucleus, cytoplasm, and ribosomes

RNA Nucleotide

Who are the “players” involved in protein

synthesis?

The “Players”

1. mRNA2. tRNA3. rRNA4. amino acids5. ribosomes

mRNA (messenger)

• linear RNA that transfers genetic information from DNA to ribosomes

tRNA (transfer)

• RNA (~80 nucleotides in length) twisted in hairpin shape

• supplies the amino acids to ribosomes for translation

rRNA (ribosomal)

• globular RNA that composes ribosomes, forms the peptide bond between amino acids during protein synthesis

Amino Acids

• monomers of proteins• linked together to form proteins during

translation

Ribosomes

• site of translation (second step of protein synthesis)

Gene Structure

Gene Structure• Promoter• Coding Region• Termination Signal

Steps of Transcription A

T G T A T C T A T A A A C C G….

RNA Splicing (editing of mRNA) A

Transcription Review(DNA to mRNA)

ABasic Transcription

mRNA codons• Codon – sequence of three nucleotides on

mRNA

The Genetic Code

Translation (mRNA to Protein)• Begins at the “start” codon - AUG

A

Codon/Anti-Codon Relationship

Translation (mRNA to Protein)• Translation continues until a “stop” codon is

reached – UAA, UGA, UAG

A

Translation Review(mRNA to Protein)

A