Download Chapter 13: RNA and Protein Synthesis

Chapter 13: RNA and Protein
Synthesis
RNA
What is RNA?
• RNA (Ribonucleic Acid)
– How is RNA physically different from DNA?
• 1. Single strand not a double
• 2. Contains Ribose and not deoxyribose
• 3. Uracil replaces thymine as nitrogen base
– DNA is the “masterplan”
– RNA are the “blueprints” for protein synthesis
What are the functions of RNA?
• 3 Main Functions
– Messenger RNA
• Carries the assembly information for each protein
– Ribosomal RNA
• Assembles the proteins from the instructions given
– Transfer RNA
• Takes amino acids to the proteins that need them
What is RNA Synthesis?
• Transcription
– Synthesis of RNA molecule from a DNA pattern
– Creation of RNA
– Complementary strand of DNA sequence
• Same as the DNA sequence hence the same bases except for uracil
– RNA Polymerase
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Enzyme
Binds to DNA
Pulls DNA apart
1 strand used to make complementary strand
• Promoters
– Tell RNA where to bind
– Looks for specific sequences to bind to
Chapter 13: RNA and Protein
Synthesis
Ribosomes and Protein Synthesis
Genetic Code
• What are amino acids?
– Building blocks of protein
– Long chains of polypeptides created out of them
– 9 “essential” amino acids
• Proteins
– Made up of different combos of amino acids
– Shape and function all determined by what amino acid
goes in it
Genetic Code
• What is Genetic Code?
– Combo of the 4 bases (A,C,G,U)
– 3 bases in a row makes an amino acid
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3 letter combos called “codons”
Some amino acids have multiple codons
Read from the center to the outside
64 different codons
– Used to create protein
• Every protein will begin with AUG (methionine)
• Certain codons will mark end of protein
Codon Table
Translation
• Process of converting amino acids to proteins
• Takes place in cytoplasm
• Step 1: Transfer RNA
– tRNA brings amino acids to ribosome based on pattern
– Also brings the anti-codon (complementary strand)
• Step 2: Joining Amino Acids
– Peptide bonds form between 1st and 2nd acid
– Breaks the bond between the amino acid and tRNA
• Step 3: Chain Grows
– Goes until it hits a stop codon
Chapter 13: RNA and Protein
Synthesis
Mutations
Types of Mutations
• What is a mutation?
– Change in the genetic material
• Gene Mutations
– Occurs during replication
– Changes are passed on in cell division
• Daughter cells will have mutation
– 1. Substitutions
• One base (A,C,G,U) is changed in sequence
• Sometimes there is no change (Example)
– 2. Insertions
• Adding a base to the sequence (Example)
– 3. Deletions
• Taking away a base from sequence (Example)
Examples
• 1. Substitutions
Examples
• 2 and 3. Insertions and Deletions
Type of Mutations
• Chromosomal Mutations
– 1. Deletions
• Removal of entire chromosome
– 2. Duplication
• Copy of chromosome made and added
– 3. Inversion
• Swapping of chromosomal positions
– 4. Translocation
• Total movement of chromosome
Examples
Chapter 13: RNA and Protein
Synthesis
Gene Regulation
Prokaryotic Gene Regulation
• How do they regulate genes?
– Through controlling transcription
– Operons
• Group of genes that can be regulated together
• Lac Operon
– Responsible for breaking down bonds when lactose is present
– Lactose found in dairy products
Prokaryotic Gene Regulation
• Role of Promoters and Operators
– Promoters
• Place where RNA polymerase binds
• Allows for transcription
– Operators
• Place where Lac repressor binds to DNA
– These are how transcription is regulated
– Lac repressor will keep things from happening when
needed
Hox Genes
• Role of Hox Genes
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Controls the formation of the body
Tells body parts where to go in development
Also tells the body when it needs to develop
Humans have them