Bio 105 1st Edition Lecture 10Current LecturePrevious lecture outline:I. Gregor Mendel and his experiment with pea plantsII. The different types of AllelesIII. Mendel’s lawsIV. Dominance RelationshipsCurrent lecture outline:I. Know the different disorders and the characteristicsII. 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 cellson 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 testosteroneLecture 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 helix1. DNA consists of two nucleotide strands2. Strands run in opposite directions- based on free carbon location3. Strands are held together by hydrogen bonds between bases4. Adenine binds with Thymine and Cytosine with Guanine- Amount of adenine always equals amount of thymine, and amount of guanine always equals amount of cytosine5. Molecule is a double helix Structure of Nucleotides in DNA- Each nucleotide consists of o Deozyribose (5-carbon sugar)o Phosphate groupo 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