* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Energy Transfer in Living Things (Chapter 6)
DNA barcoding wikipedia , lookup
DNA sequencing wikipedia , lookup
Transcriptional regulation wikipedia , lookup
Comparative genomic hybridization wikipedia , lookup
Agarose gel electrophoresis wikipedia , lookup
Holliday junction wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Promoter (genetics) wikipedia , lookup
Gel electrophoresis of nucleic acids wikipedia , lookup
Molecular evolution wikipedia , lookup
Community fingerprinting wikipedia , lookup
Transformation (genetics) wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Point mutation wikipedia , lookup
Biosynthesis wikipedia , lookup
Molecular cloning wikipedia , lookup
Maurice Wilkins wikipedia , lookup
Non-coding DNA wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
DNA Discovery Structure Replication Central Questions • What were the roles of Rosalind Franklin, James Watson and Francis Crick in determining the structure of DNA? • What are the three parts to a nucleotide? • What is base pairing? What pairs with what? • How does DNA replicate? What is DNA? Discovering DNA’s Importance DNA = deoxyribonucleic acid • 1928- Griffith- ‘something’ transferred traits • 1944- Avery identified DNA as the transforming factor • 1952- Hershey and Chase confirmed Avery’s results by radioactive tagging What does that mean? Discovery Continued • 1950’s –Rosalind Franklin got an ‘X’ pattern from X-ray crystallography of DNA –Chargaff figured out base pairing (A to T and C to G) Chromosomes • Chromosomes are long strands of DNA which contain many genes. • They are the largest genetic structures. • 1952- Watson and Crick submit model of DNA shape 1 Chromosomes You have two copies of each chromosome, each pair with the same loci, but not necessarily same copy of the gene Locus (loci) is a location on the chromosome which carries a particular gene DNA Structure • DNA is made of two connected chains of nucleotides wound into a double helix • Double – two strands Helix- spiral • Looks like a twisted ladder Genes • A gene is a unit of DNA that codes for a polypeptide (protein chain). • Genes can have several parts: –Promoter: controls where and when the gene is expressed –Open Reading Frame: coding sequence of the gene –Terminator Sequence: ends transcription –Enhancer: areas other than promoter than can ‘up production’ Nucleotide Structure • Made of nucleotides • Nucleotides are made of: Crick’s sketch Nucleotides Continued • There are 4 DNA bases: Adenine (A), Thymine (T), Cytosine (C) and Guanine (G) • In RNA Uracil (U) pairs with Adenine o Phosphatebackbone o Sugar-deoxyribose or ribose o Base-gives the ‘letter’; the code part Base Pairing • Each base is attracted to one other base by Hydrogen Bonds • Because of this bases ‘pair’ with ‘complementary’ bases • Purines (A & G) pair with pyrimidines (T & C) –A pairs with T (U in RNA) –G pairs with C 2 DNA Structure • Nucleotides link into long chains (polymers) • These chains can be described by their sequence of bases –ATGACG • Because of base pairing we know the other strand DNA Structure • Nucleotides link into long chains • These chains can be written based on their base sequence –ATGACG • Because of base pairing we know the other strand –TACTGC –? DNA Replication 1. Enzymes break hydrogen bonds DNA Replication 3. Free nucleotides pair to open strands DNA Replication 2. Strands ‘unzip’ DNA Replication 4. Two complete strands are made 3 DNA Replication • Both strands made are identical • Half of each strand is old, half is new • Therefore we say DNA replication is ‘Semiconservative’ replication Who presented the model of DNA structure we currently use? A B C D Jones and Thomas Jackson and Gray Franklin and Avery Watson and Crick What base pairs with T? A B C D C A G U Central Questions • What were the roles of Rosalind Franklin, James Watson and Francis Crick in determining the structure of DNA? • What are the three parts to a nucleotide? • What is base pairing? What pairs with what? • How does DNA replicate? What of the following make up nucleotides? A Base, sugar, phosphate B DNA, protein, sugar C Amino acids, carbon and water D Sugar, phosphate and water What do we call the structure of DNA strands? A B C D Twisted matrix Double Helix Hydrogen Bonding Single Helix 4 What is NOT a step in DNA replication? A B C D Hydrogen Bonds break Molecule ‘unzips’ Free nucleotides pair New sugars are added 5