DNA, RNA, and PROTEIN SYNTHESIS

Transcription

1 DNA, RNA, and PROTEIN SYNTHESIS 1

2 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

3 Genes & Proteins Proteins are made of amino acids linked together by peptide bonds 20 different amino acids exist 3

4 Amino Acid Structure 4

5 Polypeptides Amino acid chains are called proteins or polypeptides 5

6 RNA

7 Roles of RNA and DNA DNA is the MASTER PLAN RNA is the BLUEPRINT of the Master Plan 7

8 RNA Differs from DNA RNA has the sugar ribose DNA has the sugar deoxyribose 8

9 Other Differences RNA contains the base uracil (U) DNA has thymine (T) RNA molecule is single-stranded DNA is doublestranded DNA 9

10 Structure of RNA 10

11 . 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

12 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

13 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

14 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

15 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

16 The Genetic Code Use the code by reading from the center to the outside Example: AUG codes for Methionine 16

17 Name the Amino Acids GGG? UCA? CAU? GCA? AAA? 17

18 Remember the Complementary Bases On DNA: A-T C-G On RNA: A-U C-G 18

19 Transfer RNA (trna) Clover-leaf shape Single stranded molecule that carries an amino acid Opposite end has three nucleotide bases called the anticodon 19

20 Transfer RNA amino acid attachment site U A C anticodon 20

21 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

22 Transcription and Translation

23 Pathway to Making a Protein DNA mrna trna (ribosomes) Protein 23

24 Protein Synthesis Two phases: 1)Transcription 2)Translation 24

25 Transcription The process of copying the DNA mrna copies the template strand Requires the enzyme RNA Polymerase 25

26 Template Strand 26

27 Question: What would be the complementary RNA strand for the following DNA sequence? DNA 5 -GCGTATG-3 27

28 Answer: DNA 5 -GCGTATG-3 RNA 3 -CGCAUAC-5 28

29 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

30 mrna Transcript mrna leaves the nucleus through its pores and goes to the ribosome 30

31 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

32 Transcription Translation 32

33 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

34 Ribosomes Large subunit P Site A Site Small subunit A U G mrna C U A C U U C G 34

35 As ribosome moves along the mrna, two trna with their amino acids move into site A and P of the ribosome

36 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

37 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

38 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

39 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

40 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

41 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

42 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

43 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

44 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

45 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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