130 likes | 335 Views
Flow of Genetic Information. DNA functions as the inherited directions for a cell or organism. How are these directions carried out?. Gene. DNA. Nucleic acids. RNA. Amino acid. Protein. Flow of Genetic Information.
E N D
Flow of Genetic Information • DNA functions as the inherited directions for a cell or organism. • How are these directions carried out? Gene DNA Nucleic acids RNA Amino acid Protein
Flow of Genetic Information • An organism’s genotype is its genetic makeup, the sequence of nucleotide bases in DNA. • The phenotype is the organism’s physical traits, which arise from the actions of a wide variety of proteins. Gene DNA Nucleic acids RNA Amino acid Protein
Nucleic Acids • ●Nucleic acids are polymers of nucleotides Nitrogenous base (A,G,C, or T) • DNA, deoxyribonucleic acid • RNA, ribonucleic acid Nitrogenous base A, G, C, or U Thymine (T) Phosphate group Sugar (deoxyribose) Uracil U Phosphate Phosphate group Base Sugar Sugar ribose
Nucleic Acids Review nucleotide structure:
Nucleic Acids ●Each DNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Cytosine (C) Thymine (T) Adenine A Guanine G ● Each RNA nucleotide has one of the following bases: Adenine (A) Guanine (G) Cytosine (C) Uracil (U) Thymine T Cytosine C
DNA Structure *Early 1950’s Rosalind Franklin *1953 Watson and Crick
DNA Structure ●Nucleic Acid Structure Sugar-phosphate backbone Base pair Nucleotide Hydrogen bond Bases a DNA strand polynucleotide b Double helix two polynucleotide strands
DNA Structure Phosphate group Nitrogenous base Nitrogenous base (can be A, G, C, or T) Sugar Nucleotide Thymine (T) DNA double helix Phosphate group Sugar (deoxyribose) DNA nucleotide Polynucleotide Sugar-phosphate backbone
DNA Replication •Complementarity ”It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism … “ •Mode of DNA Replication Semiconservative
DNA Replication *Overview: DNA replication • *Complementarity determines which nucleotide will be added • *Chain elongation in a 5’-to-3’ direction
DNA Replication Initiation *Strands must separate •Helicases •SSBPs •DNA gyrase *Primase *Two are antiparallel •Continuous DNA synthesis = leading •Discontinuous DNA synthesis = lagging
DNA Replication A large team of enzymes carry out DNA replication: •Helicases •SSBPs •DNA gyrase Elongation: •Association of polymerase •Sliding clamp •Primase •DNA synthesis (DNA pol) •Primer removal and replacement (DNA pol) •Ligase closes the gaps