PROTEIN SYNTHESIS

What do you already know? What does the word “synthesis” mean? What is the building block of protein? Where in the cell are proteins made? What is the function of proteins? What 3 letters do all sugars end with?

Central Dogma of Molecular Biology DNA is transcribed into RNA which is translated into protein. DNA (Gene) RNA Protein Transcription Translation Translation RNA Transcription Protein

Picture of Dogma Nucleus Cytoplasm

Structure of RNA Ribose Sugar Phosphate group Nitrogenous bases- AU (not T) C G Forms a nucleotide (just like DNA)

Post-it Activity: 1. On your post-it notes write 2 things that only DNA has 2 things that only RNA has 1 thing in common 2. Place your post-it on the appropriate poster. Post-it Activity:

RNA differs from DNA DNA has a sugar deoxyribose 1. RNA has a sugar ribose DNA has a sugar deoxyribose 2. RNA contains uracil (U) DNA has thymine (T) 3. RNA molecule is single-stranded DNA is double-stranded

Remember the Central Dogma

3 Main Types of RNA Messenger RNA (mRNA) – carries the message from DNA (in the nucleus) to the ribosomes. Ribosomal RNA (rRNA) – combines with proteins to form ribosomes, the site of protein synthesis. Here amino acids are linked together to form a protein. Transfer RNA (tRNA) – carries amino acids from the cytoplasm to the ribosomes. Mr. T

Transcription – Basics Process that makes mRNA (messenger RNA) from a gene (DNA) mRNA carries the genetic codes from the nucleus to the ribosomes Occurs in the nucleus

Transcription – DNA  mRNA DNA unzips into 2 separate strands 2. Enzymes pair up nucleotides according to RNA base pairing rules: Cytosine(C) pairs with Guanine(G) Uracil(U) pairs with Adenine(A) 3. A single strand of RNA has been produced. 4. Genetic code from DNA is transferred to mRNA

DNA- TAC CGG ATA CCG CAT GCG RNA- AUG GCC UAU GGC GUA CGC So, after transcription, what is the complementary mRNA strand from the following strand of DNA? DNA – AGG CTT GGC CAA GCT RNA –UCC GAA CCG GUU CGA DNA- TAC CGG ATA CCG CAT GCG RNA- AUG GCC UAU GGC GUA CGC

Brain Break Find classmates that will help you complete the sequence of protein synthesis. Once you have all the pieces (5 total), working with your group organize the picture/words into the correct order. Have a teacher check your work then copy your sequence into your notes

Translation – mRNA  protein Process where mRNA is used to make proteins. Occurs at the ribosomes Ribsomes are made of rRNA (ribosomal RNA)

Translation – mRNA  protein 1. The mRNA leaves the nucleus and goes to the ribosomes. 2. The ribosome attaches to mRNA The mRNA is read by ribosomes 3 nucleotides (codon) at a time 4. As the codons are read, tRNA (transfer RNA) brings the appropriate amino acids and they are assembled in a long chain called a protein

Protein Synthesis Simulation http://www.wisc-online.com/objects/index_tj.asp?objID=AP1302

Flow Map Organize the pieces into the correct order Have a teacher check your answer Copy the correct sequence into your notes.

The Genetic Code 3 RNA nucleotides code for 1 amino acid. The strand AAACGUUCGCCC would be separated as AAA-CGU-UCG-CCC How do we figure out the amino acids? -we use the codon chart Lysine – Arginine – Serine – Proline

Genetic Codes

Universal Genetic Code DNA mRNA codon tRNA anticodon Amino Acid G T U A C C A G U Histodine A T G A U G Tyrosine G C A C G U Arginine

Protein Synthesis Amino acid protein tRNA Ribosome rRNA mRNA

Protein Synthesis DNA → RNA → Proteins Translation Transcription F E C Amino acids tRNA F E mRNA C D G Ribosome rRNA Protein A B I DNA making mRNA DNA Translation H DNA → RNA → Proteins Transcription

Quick Review 1. How many nucleotides are needed to code for one amino acid? 1 3 4 6

Quick Review 2. Uracil is found in….. DNA RNA Ribosomes Double Helix

Quick Review 3. What is one role of transfer RNA in the cell? preparing the genes for messenger RNA changing nitrogen bases into amino acids preparing messenger RNA for the ribosomes carrying amino acids to the ribosomes

Quick Review 4. The genetic information for making a protein must move from the nucleus to the cytoplasm. Which of these moves this information to the cytoplasm? a ribosome DNA RNA an amino acid

Quick Review 5. Which of these statements best explains how genes and proteins are related? Genes are segments of DNA that code for proteins. Proteins are segments of DNA that code for genes. Genes are the building blocks of proteins. Proteins are the building blocks of genes.