* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Biology 105
Survey
Document related concepts
Comparative genomic hybridization wikipedia , lookup
Agarose gel electrophoresis wikipedia , lookup
List of types of proteins wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Maurice Wilkins wikipedia , lookup
Community fingerprinting wikipedia , lookup
Gel electrophoresis of nucleic acids wikipedia , lookup
DNA vaccination wikipedia , lookup
Molecular evolution wikipedia , lookup
Molecular cloning wikipedia , lookup
Transformation (genetics) wikipedia , lookup
Non-coding DNA wikipedia , lookup
DNA supercoil wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Vectors in gene therapy wikipedia , lookup
Transcript
Biology 105 Chapter 12: DNA - The Carrier of Genetic Information Pages 263-281 Student Outcomes • Summarize the discovery of the DNA structure in the 1940-50’s • Sketch how nucleotides link together to form a DNA strand • Summarize the process of how DNA replicates. Student Outcomes • Explain the connections between telomerase and cell aging and cancer. DNA as genetic material • Transformation - process of changing the genetic makeup of an organism by an another organism. • Viruses are now used to introduce changes in DNA of the host DNA structure In 1953 - Watson and Crick proposed the double helix model of DNA DNA is made of a nucleotide: deoxyribose - sugar phosphate 1 of 4 nitrogenous bases Nitrogenous bases Two Types Purines Adenine (A) Guanine (G) Pyrimidines Thymine (T) Cytosine (C) The ratio of Purines to Pyrimidines is equal DNA Replication • Known as semi-conservative replication. DNA strands break at the hydrogen bonds(unzips). Each separate strand becomes a template for the other. • This type of replication allows mutations to continue once they occur. DNA replication continued • Each strand must untwist and unzip. Controlled by enzymes known as DNA helicases. • SSB’s then stabilize the DNA so that it doesn’t recoil. (single-strand binding proteins) • DNA polymerases catalyze the linking of the new nucleotides. DNA replication continued An RNA primer is needed at the beginning point of DNA replication. This primer is synthesized by DNA primase The RNA primer is later filled in with DNA Telomeres • End caps of chromosomes • These are short noncoding DNA repeats • Each time DNA replicates (a cell duplicates • itself) part of the telomere does not replicate and is lost. DNA can replicate many times. However, eventually important and essential coding DNA may be lost Cell Aging • Telomerase is a DNA replication enzyme which can lengthen the Telomeres. Somatic cells do not have this but germ cells do. • Shortening of telomeres contribute to cell aging and cell death • Cancer cells have the DNA Telomerase which allows many uncontrolled replications. Chromosomal mutations Occur in either mitosis or meiosis 4 types: Deletion Inversion Translocation Nondisjunction Gene Mutations • Detectible and heritable change in the genetic material - not caused by genetic recombination! • Occurs at the gene level. • Caused by Mutagens - physical or chemical agent Gene Mutations • Base-Pair Substitution Mutation AT is replaced with a GC Three types: Missense-the change results in a different codon Nonsense-the change results in an ending codon UAC, UAA, UGA Neutral - change does not result in a different amino acid Gene Mutations • Frameshift mutation – The addition or deletion of a base pair of a gene