LO: SWBAT explain the difference between chromosome mutations and gene mutations and give an example of each. DN: Quiz HW: Review Book- Biochemistry (due Monday) Test Wednesday

Chromosome Mutation: Causes a change in chromosome number. Nondisjunction- occurs when homologous chromosomes or sister chromatids fail to separate during meiosis.

karyotype

Trisomy Vs Monosomy: 3 Copies of a 1 copy of a Chromosome Monosomy X 3 Copies of a Chromosome 1 copy of a homologous pair Down Syndrome Turner Syndrome

What causes nondisjunction to occur? No one really knows for sure, but the older the age of the mother the greater the likelihood of having a child with Down Syndrome. Trisomy 21

Chromosome Damage: Part of a chromosome is repeated. missing. Reversing a fragment of them chromosome. A fragment of one chromosome attaches to a nonhomlogous chromosome.

Down Syndrome extra Trisomy 21- _______ copy of chromosome 21 Problems with brain and eye development Problems with physical development Chance of having a baby with down syndrome increases after the age of ____ extra 35

a change in the nucleotide sequence of DNA. Gene Mutations: a change in the nucleotide sequence of DNA.

cystic fibrosis mutation in gene in chromosome 7 Buildup of thick _______ in respiratory and digestive tract Defect in gene that causes abnormally large amounts of mucus to build up __________- must have both copies of the gene mucus recessive

Tay Sachs Disease Mutation of gene on chromosome 15 Absence of __________ hexosaminidase A(hex-A) Causes a ________ to accumulate in cells- especially nerve cells Usually death by age 5 _________- must have both copies of the gene enzyme fat recessive

sickle cell anemia mutation of gene on chromosome 11 change in amino acid sequence of ____________ RBC’s are _________ shaped __________- must have both copies of the gene unable to transport ________ throughout body hemoglobin crescent recessive oxygen

PKU Mutation on gene of chromosome 12 Missing _________ to break down the amino acid phenylalanine ______________ accumulates in blood and tissue Neurological problems, mental retardation Treated with a well maintained diet- cannot consume products with phenylalanine in it- high ________ foods __________- must have both copies of the gene enzyme phenylalanine protein recessive

Huntington’s disease Dominant __________- if you have the gene, you have the disease Neurological disorders Chromosome 4 Symptoms show up ______ child bearing years after Huntington 2 Huntington video

What do these gene mutations have in common? They all affect the shape of proteins!! If we change the shape of proteins (enzymes) they will not function properly and this will affect our phenotype.