CH 10, 11 & 12 Final Exam Review

Homologous Chromosomes Pairs of chromosomes having DNA segments, or genes, for the same traits Gene is a segment of DNA

Genotype tall allele - T, is dominant to the short allele – t Possible Genotypes: TT - Tall Tt – Tall – Heterozygous (HYBRID) tt – Short

Possible Gametes Parent YyRr Remember FOIL YR Yr yR yr

Anaphase 1 - Meiosis Tetrad is being pulled apart by Spindle Fibers. Spindle fibers move the chromosomes. The number of chromosomes decrease from diploid (2n) to haploid (n).

Asexual Reproduction one parent no union of gametes offspring genetically identical to the parent Example – Binary Fission

Crossing Over

Meiosis – Metaphase 1 or 2? Metaphase 2 Because we do not see a tetrad anymore.

Fertilization The offspring that would result from this egg and sperm would be a FEMALE (XX)

Recessive vs. Dominant Parents are Dominant Bb x Bb (HE) Children could be: BB: Brown (Dominant) Bb: Brown (Dominant) bb: Blue All you need is one dominant allele to show the dominant trait.

Codominance Blood Type Roan Cow – Patches of Red and White Fur Type A - IA IA or IAi Type B - IB IB or IBi Type AB - IA IB Type O - ii Roan Cow – Patches of Red and White Fur YOU SEE BOTH PHENOTYPES not a mixture.

Nondisjunction When tetrads of sister chromatids fail to separate Can cause disorders with extra or not enough chromosomes. Down Syndrome – Trisomy 21 Extra chromosome 21

Polygenic Inheritance Multiple genes control a single trait Height This is why you can have to normal parents with A normal height child A really tall child A really short child Skin Color

Recessive Sex – linked traits Usually seen in males Because they only have one X chromosome Xb Xb - Colorblind Female XB Xb – Normal Female XB XB - Normal Female Xb Y – Colorblind Male XB Y – Normal Male

Incomplete Dominance Mixture of the traits (similar to Blended) Red x White = Pink

Incomplete Dominance If we cross 2 pink flowers we get: 25% Red 25% White

Classify Carriers (II -1 & II -4) Relationships

Classify Last set of parents in generation II – must be carriers Mom in generation also had to be a carrier

Disorders to know! Achondroplasia Albinism Cystic fibrosis stunts growth to a maximum of 1.2 m Albinism an absence of pigments in the skin, hair, and eyes Cystic fibrosis prevents cells from absorbing chloride ions, thus producing extra mucus Down syndrome Extra Chromosome 21 (Trisomy) Huntington’s disease this disorder can result in uncontrolled movements

Karyotype Trisomy 21 Down Syndrome Male X & Y

People Griffith Watson & Crick Determined that the bacteria had changed forms (because DNA was transferred = genetic material) Watson & Crick Came up with the structure of DNA (double helix)

Structure Nucleotide Phosphate Sugar Nitrogen Base

DNA Replicaiton A – T C – G Purine pairs with a Pyrimidine Notice no Uracil

Transcription A – U C – G Thymine is not present in RNA Example ATC TGA CCG = DNA UAG ACU GGC = RNA

Translation 3 base pairs AUC – Isoleucine GGG - Glycine