DNA RNA Protein Trait Protein Synthesis Gene Expression

DNA RNA Protein Trait Protein Synthesis (Gene Expression) Notes Proteins (Review) • Proteins make up all living materials

• Proteins are composed of amino acids – there are 20 different amino acids • Different proteins are made by combining these 20 amino acids in different combinations

• Proteins are manufactured (made) by the ribosomes

• Function of proteins: 1. Help fight disease 2. Build new body tissue 3. Enzymes used for digestion and other chemical reactions are proteins (Enzymes speed up the rate of a reaction) 4. Component of all cell membranes 5. Answer the first 4 questions on your protein synthesis flow chart.

Genes • Genes are the instruction manuals for our bodies. • They are the directions for building all the proteins that make our body function. • Genes are made of DNA.

Gene Expression • Not all genes are active or expressed at the same time. • Why: Because the cell would produce molecules it did NOT need – waste of energy and raw materials

• Gene expression (protein synthesis) is when the product of a gene, or a specific protein is being produced by a cell. • some genes are – rarely expressed – adrenaline • some genes are – constantly expressed – hair growth, blood pressure • some genes are expressed sometimes and turned off others – estrogen.

Making a Protein—Transcription • First Step: Copying of genetic information from DNA to RNA called Transcription Why? DNA has the genetic code for the protein that needs to be made, but proteins are made by the ribosomes—ribosomes are outside the nucleus in the cytoplasm. DNA is too large to leave the nucleus (double stranded), but RNA can leave the nucleus (single stranded).

Nucleus

• Part of DNA temporarily unzips and is used as a template to assemble complementary nucleotides into messenger RNA (m. RNA).

Nucleus m. RNA DNA A T A G C C U A U DNA

• m. RNA then goes through the pores of the nucleus with the DNA code and attaches to the ribosome.

Nucleus Original DNA m. RNA Ribosome

Making a Protein—Translation • Second Step: Decoding of m. RNA into a protein is called Translation. • Transfer RNA (t. RNA) carries amino acids from the cytoplasm to the ribosome.

These amino acids come from the food we eat. Proteins we eat are broken down into individual amino acids and then simply rearranged into new proteins according to the needs and directions of our DNA.

• A series of three adjacent bases in an m. RNA molecule codes for a specific amino acid—called a codon. • A triplet of nucleotides in t. RNA that is complementary to the codon in m. RNA—called an anticodon. • Each t. RNA codes for a different amino acid. Amino acid Anticodon

• m. RNA carrying the DNA instructions and t. RNA carrying amino acids meet in the ribosomes.

• Amino acids are joined together to make a protein. Polypeptide = Protein

Use one of the codon charts on the next page to find the amino acid sequence coded for by the following m. RNA strands. CAC/CCA/UGG/UGA ___________/______/______ AUG/AAC/GAC/UAA ___________/______/______

CAC/CCA/UGG/UGA Histidine Proline Tryptophan Stop ___________/______/______ 3 rd Base 1 st Base 2 nd Base

AUG/AAC/GAC/UAA Methionine Asparagine Aspartic Acid Stop ___________/______/______

Protein Synthesis

Movie about translation at bottom of webpage. Click on hyperlink in picture above.

VIDEO – yea…its pretty AWESOME! • http: //www. youtube. com/watch? v=D 3 f. OXt 4 Mr. OM

MUTATIONS A sequence of a gene can be changed in several ways. These changes or mutations can cause no effect to the individual (They could code for the exact same protein even with the new base) OR they can cause large effects to the individual.

Point Mutation SUBSTITUTION 3 examples of gene mutations that happen at a certain point (called point mutations): mutations 1. __substitution___ a mutation in which 1 nucleotide substitution is exchanged for another.

Mutation -- INSERTION 2. __insertion___ a mutation in which 1 or insertion more _extra nucleotides is added to DNA. G C

Mutation - Deletion 3. __deletion___ a mutation in which 1 nucleotide deletion is taken out or deleted G

Gene Mutation Example Table 1: Single-Base Mutation Associated with Sickle-Cell Anemia Sequence for Wild-Type Hemoglobin ATG GTG CAC CTG ACT CCT GAG AAG TCT GCC GTT ACT Start Val His Leu Thr Pro Glu Lys Ser Ala Val Thr Sequence for Mutant (Sickle-Cell) Hemoglobin ATG GTG CAC CTG ACT CCT GTG GAG AAG TCT GCC GTT ACT Start Val His Leu Thr Pro Val Glu Lys Ser Ala Val Thr

• http: //learn. genetics. utah. edu/content/molec ules/transcribe/ • https: //www. youtube. com/watch? v=h 5 m. Jb. P 2 3 Buo