Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Homologous recombination wikipedia , lookup
DNA repair protein XRCC4 wikipedia , lookup
DNA profiling wikipedia , lookup
DNA replication wikipedia , lookup
Microsatellite wikipedia , lookup
United Kingdom National DNA Database wikipedia , lookup
DNA polymerase wikipedia , lookup
Chapter 10 DNA RNA Protein Synthesis History of DNA 2 History of DNA Early scientists thought protein was the cell’s hereditary material because it was more complex than DNA Proteins are composed of 20 different amino acids (Monomer) in long polypeptide chains DNA only has 4 monomers called nucleotides, (A, T, G, C) 3 Transformation Fred Griffith worked with virulent S and nonvirulent R strain Pneumoccocus bacteria He found that R strain could become virulent when it took in DNA from heat-killed S strain Study suggested that DNA was probably the genetic material 4 Griffith Experiment 5 History of DNA Chromosomes are made of both DNA and protein Experiments on bacteriophage viruses by Hershey & Chase proved that DNA was the cell’s genetic material Radioactive 32P was injected into bacteria! 6 DNA Structure Rosalind Franklin took diffraction x-ray photographs of DNA crystals In the 1950’s, Watson & Crick built the first model of DNA using Franklin’s x-rays 7 Rosalind Franklin 8 9 A. Found in the ________________ of the cell B. Control _____________ synthesis and thus control cell activities C. Has shape of a ____________________(twisted ladder) D. Building block is a _______________ DNA DNA is often called the blueprint of life. In simple terms, DNA contains the instructions for making proteins within the cell. Proteins are the building blocks of life….. 11 Why do we study DNA? We study DNA for many reasons, e.g., its central importance to all life on Earth, medical benefits such as cures for diseases, better food crops. 12 In which process do organisms transfer the energy in organic molecules to ATP molecules? A) Excretion C) Digestion B) cellular respiration D) Photosynthesis Which group of organic compounds includes enzymes? A) carbohydrates B) Sugars C) Nucleic Acids D) Proteins Chromosomes and DNA Our genes are on our chromosomes. Chromosomes are made up of a chemical called DNA. CELL NUCLEUS Chromosomes Genes DNA 14 DNA Stands for Deoxyribonucleic acid Made up of subunits called nucleotides Nucleotide made of 3 things: 1. Phosphate group 2. 5-carbon sugar 3. Nitrogenous base 16 DNA Nucleotide Phosphate Group O O=P-O O 5 CH2 O N C1 C4 Sugar (deoxyribose) C3 C2 Nitrogenous base (A, G, C, or T) 17 Nucleotides O O -P O O O O -P O O One deoxyribose together with its phosphate and base make a nucleotide. O O -P O O Phosphate Nitrogenous base O C C C O Deoxyribose 18 Four nitrogenous bases DNA has four different bases: Cytosine C Thymine T Adenine A Guanine G 19 Two Kinds of Bases in DNA Pyrimidines are single ring bases. Purines are double ring bases. N N C O C C N C N N C C C N N C N C 20 PURINES = double ring structure adenine (A) “Another Guido guanine (G) Pumps” N C Adenine N C C N O N C N N C N C C C N Guanine C N N C PYRIMIDINES – single ring structure thymine (T) “Tut & Cleopatra cytosine (C) = Pyramids” N O C C O C C N C thymine N O C C N C N C cytosine Nucleotide Bases phosphate group ADENINE (A) GUANINE (G) THYMINE (T) CYTOSINE (C) deoxyribose Evidence for DNA Structure: 1) 1951 – Chargaff determines that the number of adenine always equaled the number of thymine; and the number of guanine always equaled the number of cytocine A=T and G=C This is known as CHARGAFF’S RULE (base-pairing rule) Question: If there is 30% Adenine, how much Cytosine is present? 25 Answer: There would be 20% Cytosine Adenine (30%) = Thymine (30%) Guanine (20%) = Cytosine (20%) Therefore, 60% A-T and 40% C-G 26 Question: If there is 22% thymine, how much guanine is present? 27 2) 1952 Rosalind Franklin used x-ray diffraction to observe the structure of DNA. A powerful x-ray beam was aimed at the sample and the scattering pattern was recorded on film. Showed a circular shape with “rungs” sticking into the middle. She worked with Maurice Wilkins. 3) A few weeks later Watson and Crick examined Franklin’s work and in 1953 they had determined the structure of DNA by building a model. In 1962, Watson and Crick shared the Nobel prize for their discovery. Franklin had died in 1958 and did not share the prize. WATSON WATSON AND CRICK 82 yrs old (2010) Died 2004 What are the 6 bonds we learned? Covalent Share e- Peptide Ionic Give or take e- Polar Covalent Hydrogen Weak H+ and anything (-) Holds proteins C-N-C Holds H2O together Glycosidic Holds sugar C-O-C 1) Which process removes carbon dioxide from the atmosphere rather than adding it? 2) The following equation takes place in which organelle? Carbon dioxide + Water Sugar + Oxygen A. Mitochondria C. Ribosome D. Vacuole A. Vacuoles B. Nuclei C. Ribosomes D. Mitochondria 4) Which statement best describes a cell membrane? B. Chloroplast 3) Most of the reactions by which energy from sugars is released for use by the cell happens within the A. Cellular Respiration B. Combustion of Gasoline C. Photosynthesis D. Deforestation A. Is only found in animal cells B. Is an immovable structure C. It controls reproduction is a cell D. It controls the passage of materials into the cell 5) A rotten egg gave off a foul-smelling gas containing sulfur, which decomposing compound found in an egg is the most likely source of the odor? A. Carbohydrates B. Proteins C. Lipids D. Nucleic Acids What bond holds together proteins? What are the two purines? How will we remember them? What are the base-pairing rules? Who came up with them? What is one nucleotide made up of? Is DNA a single or double strand? What bond holds together the two sides of the “ladder”? C. The Watson-Crick Model of DNA 1. Double Helix = like a twisted ladder a) backbone = __________________ rungs = _____________________ (always a purine to a pyrimidine, A-T or C-G) b) 2 sides of DNA held together by weak __________________ bonds c) backbone held together by __________________ bonds DNA Double Helix “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone The Shape of the Molecule DNA is a very long polymer. Why a polymer??? The basic shape is like a twisted ladder or zipper. This is called a double helix. One Strand of DNA The backbone of the molecule is alternating phosphates and deoxyribose sugar The teeth are nitrogenous bases. phosphate deoxyribose bases 39 Two Stranded DNA Remember, DNA has two strands that fit together something like a zipper. The teeth are the nitrogenous bases but why do they stick together? 40 C N N C C N N C O The bases attract each C and G has other because of three hydrogen bonds. hydrogen bonds Hydrogen bonds are weak but there are millions and millions of them in a single molecule of DNA. N C The bonds between cytosine and guanine C are shown here with dotted lines C C N Hydrogen Bonds holds the two strands together N C N O 41 Hydrogen Bonds, cont. When making hydrogen bonds, cytosine always pairs up with guanine Adenine always pairs up with thymine Adenine is bonded to thymine here N O C C O C C N A and T share only two hydrogen bonds C 44 P D N base N b P D N base N b P D N base N b P D N base N b Human Genome Project Project completed in 2003 where scientists sequenced 25,000 genes (short segment of dna that codes for a protein) and FOUND where they are on EACH of the 46 CHROMOSOMES! Why would we want to know where our genes are and what they do? Why does it make sense to hold the 2 strands of DNA together by weak H bonds? Bc 2 strands need to break easily to duplicate or copy DNAREPLICATION Replication Facts DNA has to be copied before a cell divides in mitosis DNA is copied during the S or synthesis phase of interphase New cells will need identical DNA strands In a DNA molecule, the letters A, T, G, and C represent 1) a. Sugars c. proteins d. Nitrogen bases In DNA, the base represented by an A always pairs with the base represented by a 2) 3) b. starches a. T b. U c. G d. C Which statement describes how DNA controls cellular activities? a. b. c. d. It regulates the concentration of molecules on both sides of the cell membrane It varies the rates of starch synthesis It coordinates active and passive transport It determines the order of amino acids in protein molecules 4) Enzyme molecules are synthesized primarily from a. monosaccharides b. fatty acids c. phospholipids d. amino acids 5) Matter made up of only one kind of atom is a(n) a. fat b. nucleus c. compound d. element DNA Replication Begins at Origins of Replication Two strands open forming Replication Forks (Y-shaped region) HELICASE pervert enzyme that unzips the DNA (genes) New strands grow at the forks S 3’ P 5’ Parental DNA Molecule 3’ S Replication Fork P 53 5’ DNA Replication Enzyme Helicase unwinds and separates the 2 DNA strands by breaking the weak hydrogen bonds Single-Strand Binding Proteins attach and keep the 2 DNA strands separated and untwisted 54 3) New complimentary bases from the cell’s nucleoplasm are added to the unraveled DNA strands by DNA POLYMERASE, and new H bonds are made between the bases. “ZIPS UP” DNA polymerase can then add the new nucleotides DNA Replication P 5’ DNA polymerase can only add nucleotides to the 3’ end of the DNA This causes the NEW strand to be built in a 5’ to 3’ direction S 3’ Nucleotide DNA Polymerase RNA Primer 57 5’ 4) Bonds form between the phosphates and sugars of the new backbone. 5) 2 DUPLICATED DNA strands are made! Each with an old and a new strand Semiconservative Model of Replication Idea presented by Watson & Crick The two strands of the parental molecule separate, and each acts as a template for a new complementary strand New DNA consists of 1 PARENTAL (original) and 1 NEW DNA Template strand of DNA Parental DNA New DNA 60 Replication starts at several points along the helix, thus allowing replication to take place at a much quicker rate. If replication did not start at several points at one time, the replication process of the chromosomes of a fruit fly would take 16 days! It actually takes approximately 3 minutes (6000 sites copied simultaneously). The cells lining the stomach divide rapidly and can replicate their DNA every 20 minutes. Bases are added at a rate of 50 – 100 bases per second. (500/sec in bacteria) DNA REPLICATION BEGINS AT MANY SITES ALONG A GIANT DNA MOLECULES Proofreading New DNA DNA polymerase initially makes about 1 in 10,000 base pairing errors Enzymes proofread and correct these mistakes The new error rate for DNA that has been proofread is 1 in 1 billion base pairing errors 63 A group of more than 20 repair enzymes recognize and remove damaged nucleotides or MUTATIONS ( wrong pairs, the oopsies) and replace them with new ones. 1) 2) 3) 4) 5) 6) 7) What are the main functions of DNA? What are the 2 types of Bonds found in DNA and the locations of each? What does Helicase do? What does DNApolymerase do? Where does replication happen? (hint: well where is DNA found) What is the shape of a DNA molecule? The process of duplicating DNA is _______. 8) What would be the complementary DNA strand for the following DNA sequence? DNA 5’-CGTATG-3’ 1) 2) 3) 4) 5) 6) 7) 8) Stores and transmits genetic info Covalent bonds b/w the phosphate and sugar backbone and Hydrogen bonds join the nitrogen bases Helicase attaches to DNA and breaks the hydrogen bonds so the strands unzip DNA polymerase attaches to the unzipped strand, identifies the unpaired base on the template strand, locates a complementary nucleotide, and attaches it. Nucleus Double helix Replication DNA 3’-GCATAC-5’ Which statement best describes the relationship between cells, DNA, and proteins? A. Cells contain DNA that controls the production of proteins B. DNA is composed of proteins that carry coded information for how cells function C. Proteins are used to produce cells that link amino acids together into DNA Which two organ systems provide materials required for the human body to produce ATP? A. reproductive and excretory C. respiratory and immune B. digestive and respiratory D. digestive and reproductive Replication must happen (Before or after) the cell divides. The sugar found in DNA is A. splendose B. glucose c. ribose d. deoxyribose Most of the oxygen in our atmosphere comes from processes carried out A. In the soil B. by animals c. in factories d. by plants QUICK REVIEW What is replication? Making ____ from ___ What are the 2 enzymes involved in replication? Who is the pervert? What are the base-pairing rules for replication? 10.2 RNA a) Same as DNA except: it is _________-stranded b) _________ replaced thymine (bonds with ___________) c) responsible for the movement of genetic info from nucleus to cytosol d) sugar = _____________ (one more oxygen atom than deoxyribose) e) Used in Transcription and translation - transcription is making mRNA from DNA in nucleus - translation is making proteins from RNA at a ribosome RNA Differs from DNA 1. RNA has a sugar ribose DNA has a sugar deoxyribose 2. RNA contains the base uracil (U) DNA has thymine (T) 3. RNA molecule is single-stranded DNA is double-stranded 4. 1 type of DNA 3 Types of RNA 73 SO IF MY DNA READ ATTACGGC….my mRNA would read UAAUGCCG THIS IS TRANSCRIPTION!!!!!!!! (covalent bonds) B. Types of RNA 1) mRNA – _____________ RNA – consists of RNA nucleotides in the form of a single uncoiled chain (gene transcirption). mRNA carries genetic info from Nucleus (DNA) to cytosol. rRNA = _______________RNA - most abundant form of RNA - consists of RNA nucleotides in the globular form - makes up the ribosomes where proteins r made, 3) tRNA = _______________ RNA 2) - translates mRNA to the amino acid - carries the amino acid to the ribosome has an _______________ to match the mRNA’s CODON (series of 3 nucleotides long) That is 3 letters ex. AAU, CGG, AUC has an _________________ to pick up the correct amino acid. Gene Transcription DNA RNA Polymerase mRNA Complementary mRNA transcript A A U Protein Synthesis The production (synthesis) of polypeptide chains (proteins) Two phases: Transcription & Translation mRNA must be processed before it leaves the nucleus of eukaryotic cells 81 DNA RNA Protein Nuclear membrane DNA Transcription Eukaryotic Cell Pre-mRNA RNA Processing mRNA Ribosome Translation Protein 82 Two Parts of Protein Synthesis….from DNA to Proteins Transcription makes an RNA molecule complementary to a portion of DNA…because DNA is too big to get out of nucleus (2 strands …..mRNA only 1 strand) Translation occurs when the sequence of bases of mRNA DIRECTS the sequence of amino acids in a polypeptide 83 Greenhouse gases in the atmosphere a. keep Earth warm b. are released mostly from greenhouses c. are valuable as fuels d. reduce holes in the ozone layer Which is an example of a biotic factor that affects the size of a population in a specific ecosystem? a. b. c. d. The The The The average temperature of the ecosystem number and kinds of soil minerals in the ecosystem number and kinds of predators in the ecosystem concentration of oxygen in an ecosystem IN the following food chain, which is the most abundant organism? Corn plants mice Snake Hawks a. corn b. mice c. snake d. hawk Plants help maintain the quality of the atmosphere by a. opening holes in the ozone layer b. causing global warming c. storing oxygen d. storing carbon dioxide Adding Nucleotides 5’ growing RNA transcript 3’ 5’ 3’ direction of transcription Addition of nucleotides in the 5’ to 3’ direction of the DNA B. Transcription (“written across”) 1) RNA polymerase attaches to a special place (called promoter) on the DNA molecule and moves along the strand, unwinding and separating the strands. 2) RNA polymerase then begins reading and copying the DNA as it goes along. RNA Polymerase Enzyme found in the nucleus Separates the two DNA strands by breaking the hydrogen bonds between the bases Then moves along one of the DNA strands and links RNA nucleotides together 87 From the supply of nucleotides in the nucleus, nucleotide pairing begins for RNA transcription (A-U, C-G); 3) Pairing of the nucleotides continues until the enzyme reaches a sequence of nucleotides on the DNA that tells it to STOP ( termination codon.) Gene Transcription DNA RNA Polymerase RNA Complementary mRNA transcript 4) The mRNA separates from the DNA, then mRNA will carry the genetic information out of the nucleus to the ribosome. Messenger RNA (mRNA) Carries the information for a specific protein to a ribosome Made up of 500 to 1000 nucleotides long Sequence of 3 bases called codon AUG – methionine or start codon UAA, UAG, or UGA – stop codons 91 Prokaryote – transcription and translation take place in the Eukaryote – Transcription takes place in the Translation in the C. Replication vs Transcription These two processes are similar except: 1) _________ replaces THYMINE in mRNA 2) The RNA completely ___________ from the DNA strand Copying of DNA to DNA is ____________ Copying of DNA to mRNA is ___________ What three things make up a nucleotide _______, ______, _______ What are t he three types of RNA? Who is the main enzyme in transcription? What does he do? He _____ the DNA and puts a ______ strand together. What are the base-pairing rules for transcription? Water is an example of a) a molecule but not a compound b) compound but not a molecule c) both a molecule and a compound neither a molecule or a compound d) What are the most common building blocks of lipids? A) glycerol and amino acids b) glycerol and fatty acids c) monosaccharides and amino acids d) monosaccharides and fatty acids The analysis of data gathered during a particular experiment is necessary in order to a) formulate a hypothesis for the experiment b) develop a research plan for the experiment c) design a control for the experiment d) draw a valid conclusion from that experiment A species scientific name includes information from a) division and genus b) genus and order c) species and phylum d) genus and species A group of related classes of organisms make up an a)genus b) order c) kingdom d) phylum DNA DNA is __________________ DNA mRNA is _________________ Occurs where ________________ Enzymes involved __________________ Occurs where ____________________ Enzyme involved __________________ Original DNA is AATTGCGCA Replicated __________________ Transcript ___________________ TRANSLATION tRNA amino acids are assembled into a polypeptide chain at the ribosome _____________ anticodons translates from ______________ codons Transfer RNA (tRNA) Made up of 75 to 80 nucleotides long Picks up the appropriate amino acid floating in the cytoplasm Transports amino acids to the mRNA Have anticodons that are complementary to mRNA codons Recognizes the appropriate codons on the mRNA and bonds to them with H-bonds 98 Who has the codon? Who has the anit-codon? Is replication involved in making a protein? Does replication occur before or after cell division? Who took an x-ray of DNA? What did it show? GLOBULAR “HAIRPIN” Why are proteins important? They literally MAKE UP cell parts and enzymes Don’t 4get… your whole body is made up of cells and every reaction needs some type of enzyme What are the monomers of proteins? Amino acids AA + AA DIPEPTIDE AA + AA + AA (or more) POLYPEPTIDE 2 or more polypeptides PROTEIN A. Overview of Protein Synthesis: an organism’s genotype (genes) is translated into its phenotype (how it looks). DNA RNA PROTEIN TRANSCRIPTION AND TRANSLATION ARE THE ONLY 2 PROCESSES INVOLVED IN MAKING A PROTEIN!!!!!! Why not replication????? sequence of bases = sequence of amino acids in a protein. A U G C T G … B. genetic code for amino acids must be at least ___________ nucleotides – A TRIPLET CODE or ______________ Set of 64 base triplets Codon -Nucleotide bases read in blocks of three on ____________ Start codon AUG Stop codon UAA, UAG, UGA The triplet code is universal for all living organisms! (WE ARE ALL CONNECTED !! – EVOLUTION) Most amino acids can be specified by more than one codon Ex. 6 codons specify leucine UUA, UUG, CUU, CUC, CUA, CUG I. Genetic Code A. Link between: gene structure (N base sequence) to protein structure (amino acid sequence). 109 II. Translation Once the mRNA reaches the ___________, the cell can begin to build a protein. A. The ________________ translates the mRNA’s code into a particular protein. 1) • • • STRUCTURE: ________-strand of RNA looped back on itself Has __________ on 1 side (matches up with mRNA codons) Has _____________ of amino acid on the other side 2) FUNCTION: to carry proper amino acid to mRNA at the ribosome Example: tRNA with anticodon GCU codes for Arginine (mRNA codon is: 1) ggu B. Process of Translation 1) 2) 3) A ______________ attaches to the mRNA at a start codon - AUG The “AUG” codon pairs with the anticodon “UAC” on a specific tRNA. This tRNA carries the amino acid __________________ Free vs. Attached Where are ribosomes found in a cell again? What are they made up of again….think? Free ribosomes in cytosol produces proteins that are used inside the cell Proteins that need to be Prepared, Packaged, and Said PEACE to be shipped outside the cell are produced by ribosomes attached to the Endoplasmic reticulum 4) 5) 2nd codon is now ”read” by the ribosome. Then a tRNA Then its amino acid is attached to the polypeptide chain An enzyme joins the first two amino acids in the chain by a PEPTIDE bond. The first tRNA is now empty and the second is holding both amino acids. The empty tRNA leaves the ribosome 5) The peptide continues to grow until the ribosome reaches a STOP CODON on the mRNA STOP CODONS: UAA UAG UGA Ribosomes tunnel small ribosomal subunit large ribosomal subunit has the binding site for has the binding site the mRNA for the tRNA intact ribosome Translation Three steps: 1. initiation: start codon (AUG) 2. elongation: amino acids linked 3. termination: stop codon (UAG, UAA, or UGA). Let’s Make a Protein ! 121 mRNA Codons Join the Ribosome Large subunit P Site A Site mRNA A U G Small subunit C U A C U U C G 122 Initiation aa1 aa2 2-tRNA 1-tRNA anticodon hydrogen bonds U A C A U G codon G A U C U A C U U C G A mRNA 123 Elongation peptide bond aa1 aa3 aa2 3-tRNA 1-tRNA anticodon hydrogen bonds U A C A U G codon 2-tRNA G A A G A U C U A C U U C G A mRNA 124 aa1 peptide bond aa3 aa2 1-tRNA 3-tRNA U A C (leaves) 2-tRNA A U G G A A G A U C U A C U U C G A mRNA Ribosomes move over one codon 125 aa1 peptide bonds aa4 aa2 aa3 4-tRNA 2-tRNA A U G 3-tRNA G C U G A U G A A C U A C U U C G A A C U mRNA 126 aa1 peptide bonds aa4 aa2 aa3 2-tRNA 4-tRNA G A U (leaves) 3-tRNA A U G G C U G A A C U A C U U C G A A C U mRNA Ribosomes move over one codon 127 aa1 peptide bonds aa5 aa2 aa3 aa4 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 128 peptide bonds aa1 aa5 aa2 aa3 aa4 5-tRNA U G A 3-tRNA G A A 4-tRNA G C U G C U A C U U C G A A C U mRNA Ribosomes move over one codon 129 aa4 aa5 Termination aa199 aa3 primary structure aa2 of a protein aa200 aa1 200-tRNA A C U terminator or stop codon C A U G U U U A G mRNA 130 End Product –The Protein! aa2 aa1 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 aa200 131 What Happens to the New Polypeptides? Some just enter the cytoplasm Many enter the ER and move through the cytomembrane system where they are processed, packaged, and transported out of cell Question: What would be the complementary RNA strand for the following DNA sequence? DNA 5’-GCGTATG-3’ 138 Answer: DNA 5’-GCGTATG-3’ RNA 3’-CGCAUAC-5’ 139 Question: If there is 15% Adenine, how much Cytosine is present? 140 35% cytosine and guanine Question: If there is 26% Thymine, how much Adenine is present? 142 26%........duh … A=T REVIEW QUESTIONs! A codon might cause any of the following events to occur EXCEPT a. the binding to a molecule with a cell. b. the starting of translation. c. the coding for an amino acid. d. the stopping of translation. A protein is a polymer consisting of a specific sequence of Amino acids Fatty acids RNA nucleotides DNA nucleotides The genetic code specifies the correlation between A DNA nucleotide sequence and an RNA sequence An mRNA sequence and a tRNA sequence An RNA nucleotide sequence and an amino-acid sequence The goal of DNA is ultimately to make a PROTEIN The function on DNA is to Store our information--- our genetic code During translation, one end of a tRNA molecule pairs with a complementary A. nucleotide sequence in DNA B. mRNA codon C. tRNA molecule D. protein molecule What is the difference between a codon and anticodon? Codon found in mRNA Anticodon found on tRNA After transcription, where does the mRNA go To a ribosome either in the cytoplasm or on rough ER tRNA Peptide bond ribosome anticodon mRNA Amino acid Who were the two scientist who discovered the DOUBLE HELIX model of DNA Watson and Crick She took an x-ray of DNA and discovered its circular shape Rosalind Franklin In what organelles can DNA be found Mitochondria and nucleus and chloroplasts