Proteins and Translation DNA RNA PROTEIN

Proteins polymers made of many repeating amino acids the type of and order of the amino acid pieces determines the protein’s structure (shape) this order is determined by the code (instructions) in mRNA the mRNA was copied from the DNA code (instructions) during transcription the structure (shape) determines if the protein can perform its function (job)

Proteins proteins have many functions EX: form most of our tissues and organs EX: form enzymes that speed up chemical reactions EX: form many types of hormones that send chemical messages in blood

RNA after Transcription after mRNA is edited, it leaves the nucleus

RNA after Transcription once it gets to the ribosome, it will help make a protein

Translation decoding of an mRNA message into a chain of attached amino acids (protein) cells use information from mRNA to produce a specific protein by linking amino acids together

Steps of Translation

TEM of a cell with stained ribosomes translation occurs at specialized cell structures called ribosomes cells can have millions of ribosomes to make all of the proteins we need TEM of a cell with stained ribosomes

TEM of a cell with stained ribosomes So what is a ribosome’s function? Make proteins! TEM of a cell with stained ribosomes

Proteins and Translation

Translation Animation Steps of Translation Translation Animation

The Genetic Code ribosomes read the language of RNA in groups of 3 nitrogen bases “triplets” of A, U, C, or G

mRNA a type of RNA that is a copy of a gene’s instructions for how to make a protein

Codons a group of three bases on an mRNA strand Start Codon (AUG) – signals the beginning of a protein chain always brings the amino acid methionine

The Genetic Code

Codons a group of three bases on an mRNA strand Start Codon (AUG) – signals the beginning of a protein chain always brings the amino acid methionine Stop Codons (UAA, UAG, or UGA) – signals for the end of protein synthesis does not code for any amino acids

The Genetic Code

Steps of Translation

tRNA a type of RNA that bonds to the mRNA and brings amino acids to the ribosome

Proteins and Translation

Steps of Translation

Anticodons a group of three bases on tRNA that bind to the mRNA codon bind in a complementary fashion (A with U, C with G) each piece of tRNA has only 1 type of anticodon and only 1 type of amino acid because codons and anticodons have to bond complementary, when a codon enters a ribosome, the same amino acid will be added to the protein each time

Steps of Translation

Genetic Code Tables based on Codons from mRNA use a mRNA Codon Table to determine the order of amino acids

Steps of Translation

Peptide Bond a special type of covalent bond that holds two amino acids together covalent bonds – electrons are shared between two amino acids

Steps of Translation

Polypeptide Chain multiple peptide bonds holding together multiple amino acids the beginning of a protein

Translation and Proteins DNA RNA PROTEIN

Protein Synthesis Concept Map transcription translation DNA RNA protein (in the nucleus) (at a ribosome)

Other Resources See the diagrams and videos on the Unit 5.1 Links section of the class wiki

Summary The parent DNA strand on the right has been transcribed into a single stranded piece of mRNA. Translate the mRNA sequence into a sequence of amino acids using the Genetic Code table. Remember, codons from mRNA get put into groups of three bases.

DNA Strands mRNA Strand Amino Acid Sequence A T U G C Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C mRNA Strand Amino Acid Sequence A T U Methionine G C Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C Arginine mRNA Strand Amino Acid Sequence A T U Methionine G C Arginine Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C Arginine mRNA Strand Amino Acid Sequence A T U Methionine G C Arginine Leucine Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C Arginine mRNA Strand Amino Acid Sequence A T U Methionine G C Arginine Leucine Threonine Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C Arginine mRNA Strand Amino Acid Sequence A T U Methionine G C Arginine Leucine Threonine Histidine Summary

The Genetic Code

Summary DNA Strands Amino Acid Sequence A T U Methionine G C Arginine mRNA Strand Amino Acid Sequence A T U Methionine G C Arginine Leucine Threonine Histidine Summary

A stop codon does not carry an amino acid. Don’t write “STOP” A stop codon does not carry an amino acid! Don’t write “STOP”!!! There is not an amino acid called “STOP”.

Thought Question… Can 1 piece of DNA be used to make many copies of the same protein? To help answer this… How is DNA involved in making a protein? What happens to DNA after its “job” is completed in protein synthesis? Can it be reused after its “job” is completed?

Thought Question… How is DNA involved in making a protein? transcription translation RNA DNA protein

Thought Question… What happens to DNA after its “job” is completed in protein synthesis? Can it be reused after its “job” is completed?

TEM of a cell with stained ribosomes Thought Question… Eukaryotic cells can contain millions of ribosomes per cell. TEM of a cell with stained ribosomes

Thought Question… Can 1 piece of DNA be used to make many copies of the same protein? RNA protein RNA protein DNA RNA protein RNA protein RNA protein

Thought Question… Can 1 piece of DNA be used to make many copies of the same protein? YES!!! …because 1 piece of DNA can be used to make many pieces of RNA and each RNA piece can be used to make a protein

Steps of Translation

Steps of Translation