Module 9: bio 101

Module 9: bio 101 19th century austrian monk - mendal did research done with pea plants - mendal developed 1st theory about trait inheritance - mendal exhibit observable characteristics - peas well suited for breeding experiment characteristics controlled by single genes - peas well suited for breeding experiment can obtain large numbers of offspring - peas well suited for breeding experiment can control pollination of pea plants - peas well suited for breeding experiment mendal observed: - -a pea -a stamen (male part) -F2 generation -a hybrid mendel observed true breeding plants that: - self-pollinated purple flowered plants that only produce purple flowered plants mendel never saw: - a chromosomal mendal called these hereditary factors but today we call them: - alleles alternative form of a gene - allele segregates into different gametes - each of 2 alleles for a given trait separation of alleles or homologous chromosomes during meiosis - segregation genetically based traits are inherited independently of each other - law of independent assortment does not apply to genes located close together on the same chromosome - law of independent assortment GG - homozygous dominant Gg - heterozygous gg - homozygous recessive GG, Gg, gg are all: - diploid individuals GG and gg are both: - homozygous How can two pea plants with different genotypes for pod color have the same phenotype? - GG or Gg Both husband and wife are carriers (heterozygous) for cystic fibrosis which means they are carriers of a: - recessive genetic disorder what are the symptoms of cystic fibrosis? - -production of abnormally thick mucus in the lungs -decreased ability to absorb nutrients from the small intestine 1/2 gametes will receive a dominant allele and 1/2 will receive recessive allele - law of segregation each square in a punnett square represents: - a fertilization event a resulting 1st cell in a punnett square is a: - zygote a husband and wife are both heterozygous (Gg) for a disorder, what are the chances that their CHILDREN will have the disorder? - 25% a husband and wife are both heterozygous (Gg) for a disorder, what are the chances that their 1ST CHILD will have the disorder? - 25% how does cystic fibrosis get passed on? - the harmful carrying allele can reside in a heterozygous parent usually lethal before reproductive age - cystic fibrosis a dominant disorder, homozygous dom (GG) and heterozygous (Gg) people develop this disorder - Huntington's disease jane's father has huntington's disease but her paternal grandfather and mother do not, what are jane's chances of developing huntington's disease? - 50% chance the genotype of an albino child has to be: - homozygous recessive Albinism is a recessive condition and can only be caused when an individual inherits 2 recessive alleles. John is an albino, John's parents are not albino's, what must be true of his parents? - -genotypes Gg -both heterozygous for albinism -both carriers of albinism father with free earlobes and mother with attached ear lobes and child has attached ear lobes, what are the chances that the next child has attached earlobes? - 50% there is a 1/4 chance for a gamete, possible due to: - independent assortment any combination of the gametes (sperm and egg) is possible because - fertilization is possible says that any sperm is produced by the husband has a equal chance of fertilizing any egg produced by the wife - random fertilizers crossing an individual with an unknown genotype with a homozygous recessive individual - test cross intermediate phenotype exists when: - heterozygote offspring of two homozygotes show an intermediate phenotype occurs in some flowering plants - incomplete dominance one phenotypic trait is controlled by many genes - polygenic trait refers to genetic control of continuously varying traits - polygenic traits polygenic human traits - -skin color -height -nose shape: many alleles involved ABO blood system contains: - 3 alleles that produce 4 phenotypes example of co-dominance in the ABO blood system? - type AB, both the A and B alleles are expressed an example of multiple allelism in the ABO blood system: - A, B, C what are the four phenotypes produced from the ABO blood system? - Type A, Type B, Type AB, Type O bloods individual can only pass this many alleles in the ABO blood system - 2 alleles single gene has an impact on more than 1 characteristic - pleiotropy example of pleiotropy - PKU inability to convert phenylalanine to tyrosine - PKU Which parent's chromosome determines the sex of the baby? - the male sex chromosome sex-linked traits expressed in different frequencies in males and females - sex determination genes located on x chromosome - x-linked gene traits females generally carry one functional version of each x-linked gene - a female carrier of a recessive allele will not exhibit disorder symptoms which chromosome has more x-linked diseases - the x chromosome since it's larger linked genes are on the: - same chromosome genes are linked when - located near each other on the ame chromosome genes that are linked do not sort: - independently when crossing over occurs - linked genes stay together