DNA Replication and Protein Synthesis DNA Deoxyribonucleic Acid
DNA Replication and Protein Synthesis
DNA • Deoxyribonucleic Acid – Controls cells activities – Contains organism’s traits – Contains messages to produce proteins
DNA • Monomer- Nucleotide
DNA
DNA- Base Pairs Adenine bonds with Thymine Cytosine bonds with Guanine
DNA- Base Pairs • Just remember: AT Central Gwinnett A bonds with T C bonds with G
DNA structure • James Watson and Francis Crick 1953 Shaped like a ladder Sides- alternating sugars and phosphates Steps-base pairs joined by hydrogen bonds
DNA Structure • Then ladder is twisted forming a double helix
DNA and RNA DNA RNA Strands Double strand Single strand Sugar Deoxyribose Base pairs A-T C-G A-U C-G Location Nucleus only Uracil is substituted for thymine Moves from nucleus to cytoplasm
DNA and RNA
DNA Replication • During mitosis- chromosomes (DNA) are copied (replicated) • Every cell gets a complete set of chromosomes • Replication- process in which DNA is copied
DNA Replication • Steps to DNA replication – 1. Chemical bonds split between base pairs, DNA is unzipped – 2. Free nucleotide bases pair up with complementary base on DNA strands. Each original strand is called a template. – 3. Sugars and phosphates bond between free nucleotides – 4. Result is 2 identical molecules of DNA. Each new molecule consists of one old strand one new strand
DNA Replication
DNA Replication Note: Each new DNA molecule is made of one old strand one new strand
DNA Replication Links • http: //www. lpscience. fatcow. co m/jwanamaker/animations/DNA% 20 Replication%20%20 long%20. html
Crack the Code • Take these numbers and convert them into letters of the alphabet, then translate it into a word. 3, 5, 14, 20, 18, 1, 12 WHAT DID YOU GET? HOW DID YOU ARRIVE AT YOUR ANSWER
Central Dogma of Gene Expression
Let’s Watch the Process of Protein Synthesis • http: //www. youtube. com/watch? v=983 lhh 20 r. GY
Protein Synthesis Transcription and Translation • Transcription- one side of a DNA molecule is copied forming a m. RNA molecule. Occurs in the nucleus • Translation- protein is formed by joining Amino Acids -sequence of m. RNA bases is converted into an amino acid sequence. Occur in the ribosome
Types of RNA m. RNA t. RNA r. RNA
Protein Synthesis Transcription • 1. DNA unzips • 2. Free floating nucleotides bond to one side of DNA (Uracil bonds with Adenine) • 3. Nucleotides are joined together • 4. m. RNA leaves the nucleus and enters the cytoplasm
Protein Synthesis Translation • Codon- set of three bases on m. RNA, each one codes for one amino acid
Protein Synthesis Steps of Translation • • • 1. Ribosome attaches to m. RNA 2. t. RNA with anti-codon that is the complement of the codon attaches to m. RNA carrying a specific amino acid 3. Ribosome slides to second codon 4. Second t. RNA with complementary anticodon bonds with second codon 5. Amino acid from 1 st t. RNA bonds with amino acid attached to 2 nd t. RNA 6. Ribosome continues down m. RNA creating a chain of amino acids until a stop codon is reached
3 Types of RNA • A- r. RNA- ribosomal RNAbonds with m. RNA, site where t. RNA brings amino acids to form a protein • B- t. RNA- transfer RNAcarries the amino acids to make a protein. Carries them to the ribosome and m. RNA. • C- m. RNA- messenger RNAsingle strand copied from one side of the DNA molecule in the nucleus. Moves to the cytoplasm. “Carries the message”
Protein Synthesis Translation Determine the chain of Amino Acids for the following codons AUG CAG UAU GUU UUA CCU UAG Methionine Glutamine Tyrosine Aspartate Valine Leucine Proline Stop
Protein Synthesis Translation Anti-codon- three bases on the t. RNA molecule that is the complement to the bases in a codon.
Protein Synthesis Steps of Translation
TC G TTC A AA template Strand AG T T C AAGT U C G UU C A A A m. RNA
A A TTC G A C T template Strand AG T T C AAGT U C G UU C A A A Nucleus m. RNA Cytoplasm Ribosome
A A TTC G A C T Template Strand AG T T C AAGT U C G UU C A A A Nucleus m. RNA Cytoplasm U C G UU C A A A
A A TTC G A C T Template Strand AG T T C AAGT Nucleus Cytoplasm 1 AA s t. R ’ A N C G A U CG UU C A A A
A A TTC G A C T template Strand AG T T C AAGT Nucleus AA 1 Cytoplasm t. RNA’s AGC U C G UU C A A A
A A TTC G A C T template Strand AG T T C AAGT Nucleus ATP AA 1 • AA 2 Cytoplasm t. RNA’s AGC AAG U C G UU C A A A
A A TTC G A C T AG T T C AAGT Template Strand AA 1 Nucleus ATP AA 1 • AA 2 AA 3 Cytoplasm AG C AAG U U C G UU C A A A
A A TTC G A C T template Strand AG T T C AAGT AA 1 Nucleus AA 1 • AA 2 AA 3 AGC Cytoplasm AAG U U C G UU C A A A
A A TTC G A C T Template Strand AG T T C AAGT AA 1 Nucleus AA 1 • AA 2 AA 3 AGC Cytoplasm AAG U U C G UU C A A A
A A TTC G A C T AG T T C AAGT Template Strand AA 1 Nucleus AA 1 • AA 2 AA 3 AGC Cytoplasm AA G UUU U C G UU C A A A
Protein Synthesis links • http: //www. lpscience. fatcow. co m/jwanamaker/animations/Protei n%20 Synthesis%20%20 long. html • http: //www. wisconline. com/objects/index_tj. asp? objid=AP 1302
Mistakes in the Genetic Code • Mutation- a change in the genetic code • Mutagen- any substance that causes a mutation to occur – Examples: chemicals, radiation, high temps
Types of Mutations • 1. Substitution mutation- change in one base pair, often has no effect on phenotype • Example GGU = glycine GGC = glycine
Types of Mutations • 2. Frame shift mutation- deletion or addition of a base – Codons get shifted Example: GGG CUU CCU ACU Gly Leu Pro Thr Suppose third G in first codon is lost, then: GGC UUC CUA CU Gly Phe Leu
Types of Mutations • 3. Inversion mutation- part of the genetic code breaks off and is inserted in reverse order • AUCCGCUCUAA • AUCUCGCCUAA
Types of Mutations • 4. Chromosomal mutation- whole chromosome is added or deleted – Caused by non-disjunction
Genetic Technology • Selective breeding- farmers choose organisms with desirable traits to breed – Increases frequency of desired allele in population • Genetic Engineering- faster method of increasing desired allele in population – Small fragment of DNA is cut or cleaved from one organism and fragment is inserted into a host organism – Also called recombinant DNA- connecting fragments of DNA from different sources Transgenic organism- organism containing fragments of foreign DNA
Genetic Technology Gel Electrophoresis • Fragments of DNA are separated by weight • Matching bands can be used to identify the source of the DNA • Link: http: //www. lpscience. fatcow. co m/jwanamaker/animations/Chro m%26 Elpho. html
Gel Electrophoresis
DNA Fingerprinting • Which suspect committed the crime? Suspect 2
DNA Fingerprinting Various DNA samples in an assault investigation are shown in the figure on the right. • Blood samples of DNA were loaded into the following lanes: • 1 - known blood sample of the victim • 2 - known blood sample from the defendant • 3 - female fraction from a swab of the victim • 4 - male fraction from the swab of the victim What can you conclude about the defendant/suspect? • He is guilty • Suspect might be guilty, but more evidence is needed • Swab is from the wrong victim • The suspect must be excluded as a source of the DNA in the evidence • NONE of the above Blood samples victim 1 Swab from victim defendant 2 female fraction 3 male fraction 4
DNA Fingerprinting 1 • The DNA finger print analysis of a man and his four children are shown in the figure. Which lane contains the DNA of the father? Lane 3 2 3 4 5
DNA Fingerprinting • DNA fingerprint analysis is shown for a single locus for a man, a woman, and their four children. Which child is least likely to be the offspring of this couple? Child 2 Child 1 Child 2 Mother Father Child 3 Child 4
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