Protein Synthesis Chapter 13 Protein Synthesis How does

Protein Synthesis Chapter 13

Protein Synthesis Ø How does your DNA eventually lead to your different phenotypes (hair color, eye color, etc)

RNA Ø RNA is a nucleic acid (like DNA) which is made up of nucleotides EXCEPT its sugar is ribose instead of deoxyribose and it has Uracil instead of Thymine. Bases: Adenine (A), Guanine (G), Cytosine (C), & Uracil (U) that bonds with A in RNA

RNA Ø RNA is also only single-stranded, while DNA is doublestranded.

Three types of RNA Ø 1. Messenger RNA (m. RNA) – carries genetic information from DNA in the nucleus out to the ribosomes in the cytoplasm.

Three types of RNA Ø 2. Transfer RNA (t. RNA) – single chain folded into a hairpin shape that binds to specific amino acids

Three Types of RNA Ø 3. Ribosomal RNA (r. RNA) – Proteins are assembled on ribosomes which are made of subunits. These subunits are made of several ribosomal RNA.

Protein Synthesis Ø Protein Synthesis = Transcription + Translation

Steps of Transcription Ø 1. Sections of DNA unzip, exposing the base pairs, by using RNA polymerase. Ø 2. Pieces of m. RNA come to the DNA strand match to the proper base starting at the promotor region. ***Note – Uracil takes the place of Thymine and bonds to Adenine

Steps of Transciption Ø 3. This continues until a complete strand of m. RNA is made

m. RNA sometimes needs a bit of editing before it is able to be read (kind of like the rough draft of a term paper!) Ø Introns are portions of the m. RNA that are cut out before it leaves the nucleus. Ø Exons are the remaining portions that are spliced back together to form the final m. RNA strand. Ø RNA Editing

Translation Ø Translation = the process by which m. RNA is converted into a string of amino acids (building blocks of protein) Ø Translation happens in the ribosomes floating in the cytoplasm

Steps of Translation 1. m. RNA strand from transcription breaks away from the DNA & moves into a ribosome floating in the cytoplasm. Ø 2. Floating in the cytoplasm are loose t. RNA pieces that contain an anticodon – a sequence of 3 nucleotides Ø

Steps of Translation 3. t. RNA anticodons match up with their complementary codons on the m. RNA molecule. The t. RNA brings along the correct amino acid Ø 4. A chain of amino acids is joined to make a specific protein. Ø

Codons and Anticodons Ø A codon specifies a particular amino acid Ø Both codons and anicodons are sequences of three base pairs. Ø Example: AUG or UAG or CGA Ø AUG signifies the start of an amino acid sequence.

Final Product = Proteins Ø Proteins – organic molecules made up of amino acids. Ø There are 20 amino acids Ø Proteins do such things as control biochemical pathways, direct the production of lipids, and take responsibility for cell movement.

Protein Synthesis Animation Ø Protein Synthesis Animation