Protein Synthesis

Profiles: Francois Jacob and Jacques Monod

-Proposed the operon model of gene regulation by studying the lac genes in E.Coli. -Stated in their original hypothesis that genes had one regulatory process. -Tested hypothesis and learned E.Coli has two regulatory processes.

Reviewing the Process of Transcription

-Proteins are responsible for the structures and functions of organisms. -Transcription is the synthesis of mRNA. -What begins the process of transcription? RNA polymerase -The study of E. coli led scientists to new experimental designs for studying operons. How did scientists begin studying operons? They began reading the genome sequence of organisms to determine the number and organization of operons.

DNA: Deoxyribonucleic Acid

DNA: Deoxyribonucleic Acid: A double-stranded helical polymer containing the sugar deoxyribose, a phosphate group, and the bases adenine, cytosine, guanine, and thymine. -Contains the genetic information for living organisms -Codes for the synthesis of proteins

Identifying the Steps of Translation

How are the order of codons determined? -The DNA sequence determines the order. What is needed for translation to occur? Check all that apply. -mRNA -ribosome -tRNA -codons

What is the purpose of proteins, and how are they synthesized

Protein ⇒ Transcription ⇒ Translation

Protein synthesis

Proteins: -are formed from amino acids and are responsible for the structures and functions of organisms. -are synthesized on ribosomes, organelles that produce proteins for the cell.

RNA: Ribonucleic Acid

RNA: Ribonucleic Acid: A single-stranded nucleic containing the sugar ribose, a phosphate group, and the bases adenine, cytosine, guanine, and uracil. -Moves the DNA code for protein synthesis from the nucleus to ribosomes.

Identifying the Impact of E. coli

Scientists hypothesized that E. coli contained one operon. After further experimentation, they discovered that, in fact, E. coli contained two operons. Using this information, answer the questions provided What is one way scientists are able to study operons in organisms? -by studying the number and organization of operons by reading the genome sequence What is the purpose of operons in protein synthesis? -They contain promoters and operators that determine when a gene is transcribed.

Recalling the Role of Genes

Segments of ⇒ DNA transferred from parent to offspring are called genes. Genes determine the ⇒ traits of organisms.

Reviewing the Steps of Transcription

Step 1: Free RNA nucleotides pair with the complementary DNA nucleotides on one strand of DNA. Step 2: The mRNA molecule breaks away as the DNA strands rejoin. Step 3: RNA polymerase unzips the DNA molecule.

Reviewing Translation and Gene Expression

Step 2:A peptide bond is created between the first two amino acids formed. Step 4:Once a protein is formed, the gene for a particular trait is expressed. Step 3:A chain of amino acids is formed, creating a protein. Step 1:The first codon of mRNA attaches to a the anticodon of tRNA to form a chain of amino acids.

Determining the Steps of Protein Synthesis

Step 5: Once the protein is made, the gene for a particular trait is expressed. Step 3: mRNA joins the ribosome, and the anticodons from tRNA join mRNA to form a chain of amino acids. Step 1: RNA polymerase unzips DNA and free RNA nucleotides join DNA to form mRNA. Step 4: A chain of amino acids is formed from peptide bonds, creating a protein. Step 2: mRNA is transported from the nucleus of the cell to the ribosomes of the cell.

Identifying the Structures of DNA and RNA

The nucleic acid DNA: Deoxyribonucleic Acid contains the genetic information for all of the structures and functions of an organism? RNA: Ribonucleic Acid is a single-stranded nucleic acid that moves the DNA code for protein synthesis from the nucleus to the ribosomes .

Transcription

Transcription is the synthesis of mRNA (messenger RNA) from a DNA template with the aid of RNA polymerase. mRNA: A form of RNA that carries the synthesized genetic information from the nucleus of the cell to the ribosomes for protein production. Repressor gene ⇒Promoter(RNA polymerase) ⇒ Operator(Repressor protein) ⇒ Enzyme 1 ⇒ Enzyme 2 ⇒ Enzyme 3

Reviewing the Process of Translation

Translation involves tRNA, a form of RNA that brings amino acids to the ribosomes to be assembled into proteins. Identify the three main stages of translation. Check all that apply. 1. elongation 2.termination 3.initiation At what point during protein synthesis are genes expressed? -When the protein for a particular gene is formed, the gene is expressed.

Translation

Translation: The process of converting the sequence of nitrogen bases in the mRNA (messenger RNA) into a sequence of amino acids for protein production. 5'CAGAUGUACGGACGAUAA'3 ⇒ mRNA strand Translation occurs on ribosomes and involves tRNA (transfer RNA), a form of RNA that brings amino acids to the ribosomes to be assembled into proteins. Each mRNA condon must join with the anticondon of the proper tRNA.