DNA, RNA, and PROTEIN SYNTHESIS 1
DNA DNA contains genes, sequences of nucleotide bases The genes code for polypeptides (proteins) Proteins are used to build cells and do much of the work inside cells Oscar was here lol
Genes & Proteins Proteins are made of amino acids linked together by peptide bonds 20 different amino acids exist 3
Amino Acid Structure 4
Polypeptides Amino acid chains are called proteins or polypeptides 5
RNA
Roles of RNA and DNA DNA is the MASTER PLAN RNA is the BLUEPRINT of the Master Plan 7
RNA Differs from DNA RNA has the sugar ribose DNA has the sugar deoxyribose 8
Other Differences RNA contains the base uracil (U) DNA has thymine (T) RNA molecule is single-stranded DNA is doublestranded DNA 9
Structure of RNA 10
. Three Types of RNA Messenger RNA (mrna) copies DNA s code & carries the genetic information to the ribosomes Ribosomal RNA (rrna), along with protein, makes up the ribosomes Transfer RNA (trna) transfers amino acids to the ribosomes where proteins are synthesized 11
Messenger RNA Long straight chain of nucleotides Made in the nucleus Copies DNA & leaves through nuclear pores Contains the nitrogen bases A, G, C, U (no T) 12
Messenger RNA (mrna) Carries the instructions for building a specific protein Made up of 500 to 1000 nucleotides Sequence of 3 bases is called a codon Each codon represents an amino acid 13
Ribosomal RNA (rrna) rrna is a single strand 100 to 3000 nucleotides long Globular in shape Made inside the nucleus of a cell Associates with proteins to form ribosomes Site of protein synthesis 14
The Genetic Code Some codons tell the ribosome to start or stop translating AUG methionine or start codon UAA, UAG, or UGA stop codons 15
The Genetic Code Use the code by reading from the center to the outside Example: AUG codes for Methionine 16
Name the Amino Acids GGG? UCA? CAU? GCA? AAA? 17
Remember the Complementary Bases On DNA: A-T C-G On RNA: A-U C-G 18
Transfer RNA (trna) Clover-leaf shape Single stranded molecule that carries an amino acid Opposite end has three nucleotide bases called the anticodon 19
Transfer RNA amino acid attachment site U A C anticodon 20
Codons and Anticodons The 3 bases of an anticodon are complementary to the 3 bases of a codon Example: Codon ACU Anticodon UGA UGA ACU 21
Transcription and Translation
Pathway to Making a Protein DNA mrna trna (ribosomes) Protein 23
Protein Synthesis Two phases: 1)Transcription 2)Translation 24
Transcription The process of copying the DNA mrna copies the template strand Requires the enzyme RNA Polymerase 25
Template Strand 26
Question: What would be the complementary RNA strand for the following DNA sequence? DNA 5 -GCGTATG-3 27
Answer: DNA 5 -GCGTATG-3 RNA 3 -CGCAUAC-5 28
Transcription The DNA strand separates (like with replication) RNA Polymerase then uses one strand of DNA as a template to assemble nucleotides into mrna 29
mrna Transcript mrna leaves the nucleus through its pores and goes to the ribosome 30
Translation Translation is the process of decoding the mrna into a polypeptide chain (protein) Ribosomes read mrna 1 codon at a time and construct the proteins 31
Transcription Translation 32
Ribosomes Made of a large and small subunit Composed of rrna (40%) and proteins (60%) Have two sites for trna attachment --- P and A 33
Ribosomes Large subunit P Site A Site Small subunit A U G mrna C U A C U U C G 34
As ribosome moves along the mrna, two trna with their amino acids move into site A and P of the ribosome
Initiation aa1 aa2 anticodon hydrogen bonds 1-tRNA U A C A U G codon 2-tRNA G A U C U A C U U C G A mrna 36
Elongation peptide bond aa1 aa2 aa3 anticodon hydrogen bonds 1-tRNA U A C A U G codon 2-tRNA 3-tRNA G A A G A U C U A C U U C G mrna 37 A
aa1 aa2 peptide bond aa3 1-tRNA U A C (leaves) 2-tRNA 3-tRNA G A A G A U A U G C U A C U U C G A Ribosomes move over one codon mrna 38
aa1 peptide bonds aa4 aa2 aa3 4-tRNA 2-tRNA 3-tRNA G C U A U G G A U G A A C U A C U U C G A A C U mrna 39
aa1 peptide bonds aa2 aa3 aa4 G 2-tRNA A U (leaves) 3-tRNA 4-tRNA G C U G A A A U G C U A C U U C G A A C U Ribosomes move over one codon mrna 40
aa1 aa2 peptide bonds aa3 aa4 aa5 5-tRNA U G A 3-tRNA 4-tRNA G A A G C U G C U A C U U C G A A C U mrna 41
aa1 aa2 peptide bonds aa3 aa4 aa5 5-tRNA 3-tRNA G A A 4-tRNA G C U G C U A C U U C G A A C U Ribosomes move over one codon U G A mrna 42
aa4 aa5 aa199 Termination aa3 aa2 primary structure of a protein aa200 aa1 200-tRNA terminator or stop codon A C U C A U G U U U A G mrna 43
End Product The Protein! aa2 The end products of protein synthesis is a primary structure of a protein A sequence of amino acid bonded together by peptide bonds aa3 aa4 aa5 aa199 aa1 aa200 44
Messenger RNA (mrna) mrna start codon A U G G G C U C C A U C G G C G C A U A A codon 1 codon 2 codon 3 codon 4 codon 5 codon 6 codon 7 protein methionine glycine serine isoleucine glycine alanine stop codon Primary structure of a protein aa1 aa2 aa3 aa4 aa5 aa6 peptide bonds 45
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