Bio 105 1st Edition Lecture 10 Current Lecture Previous lecture outline I II III IV Gregor Mendel and his experiment with pea plants The different types of Alleles Mendel s laws Dominance Relationships Current lecture outline I II Know the different disorders and the characteristics Know the difference between DNA and RNA and its characteristics Achondroplasia autosomal dominant disorder Homozygous leads to stillbirth Heterozygous display a type of dwarfism Incompletely Dominant Disorders Familial hypercholesterolemia affects the number of LDL cholesterol receptors on cells on cells Homozygous for defective genes has no receptors cannot process cholesterol have high blood cholesterol levels develop cardiovascular disease in teenage years Heterozygous individual have half the normal number of receptors and elevated blood levels X Linked Recessive Inheritance Males show disorder more than females Son cannot inherit disorder from his father because father must give Y to son Father passes disorder to daughter Mother passes disorder to son Chromosomal Disorders disorders can come from changes in chromosomal structure such as Deletions and mutations in part of a chromosome Deletion breaks in a chromosome which result in loss of genes William Syndrome chromosome 7 loses an end piece usually the individual has a turned up nose wide mouth with small chin poor academic skills but well developed verbal and musical skills Cri du chat Syndrome chromosome 5 loses an end piece usually the individual has a small head mental retardation cat like cry Aneuploidy loss or gain of a full chromosome Polyploidy complete extra set of chromosomes Down syndrome extra chromosome 21 Trisomy of chromosome 21 Mental impairment and a variety of additional defects Can be detected before birth Risk of Down Syndrome increases dramatically when mothers are over age 35 greater chance of non disjunction in older eggs completing meiosis Turner Syndrome Inheritance of only one X XO 98 spontaneously aborted Survivors are short infertile females Klinefelter Syndrome XXY condition Results mainly from nondisjunction in mother 67 Phenotype is tall males sterile or nearly so feminized traits sparse facial hair somewhat enlarged breasts XYY Conditon Jacob s syndrome Taller than average males Most otherwise phenotypically normal Some mentally impaired Once thought to be predisposed to criminal behavior many were institutionalized but studies now discredit this Extra testosterone Lecture 17 DNA Synthesis Protein Synthesis RNA Johann Miescher Discovered DNA he called it nuclein Griffith Discovered Transformation The harmless R cells had been transformed by material from the dead pathogenic S cells Structure of DNA in 1953 Watson and Crick showed that DNA is a double helix 1 DNA consists of two nucleotide strands 2 Strands run in opposite directions based on free carbon location 3 Strands are held together by hydrogen bonds between bases 4 Adenine binds with Thymine and Cytosine with Guanine Amount of adenine always equals amount of thymine and amount of guanine always equals amount of cytosine 5 Molecule is a double helix Structure of Nucleotides in DNA Each nucleotide consists of o Deozyribose 5 carbon sugar o Phosphate group o A nitrogen containing base there are four bases Adenine Guanine Thymine Cytosine Adenine pairs up with Thymine AT Guanine pairs up with Cytosine GC RNA Also a nucleic acid but single stranded Also has a slightly different sugar Uracil Uracil instead of Thymine so Guanine binds with Cytosine Adenine binds to Uracil not Thymine DNA Structure helps explain how it duplicates DNA is two nucleotide strands held together by hydrogen bonds Hydrogen bonds between two strands are easily broken Each single strand than serves as template for new strand DNA Replication semi conservative every ne DNA molecule is half old half new