Human Red Blood Cells 1.Contain the protein, hemoglobin (Hb) 2.O 2 binds to Hb = oxygenated blood 3.Red Blood Cells are doughnut shaped cells

Sickle Cell Anemia 1.RBC’s are “sickled shape” 2.Hemoglobin protein has been altered -shape has changed 3.Cells stick to each other; Oxygen binding capacity has been altered. 4.Circulatory problems arise Why?

Gene Mutation 1.A change in the DNA 2.A change in the sequence of nitrogenous bases: A, T, C or G 3.Carcinogens can cause the change

Normal Hemoglobin: Valine-Histidine-Leucine-Threonine-Proline-Glutamic Acid-Glutamic Acid Abnormal Hemoglobin: Valine-Histidine-LeucineThreonine-Proline-Valine-Glutamic Acid Sickle Cell Anemia had change in the polypeptide chain: Glutamic acid is changed to Valine Why??????? How can this be??????????????

Change Affects Codon Normal Hb DNA = CTT mRNA = GAA = Glutamic acid -Proline-Glutamic Acid-Glutamic Acid- Sickle Hb DNA = CAT mRNA = GUA = Valine -Proline-Valine-Glutamic Acid- This results from mutated DNA! Base-pair substitution = replacement of one nitrogenous base This is also referred to as a point mutation.

Frameshift Mutations 1.Changes the reading of the DNA 2.Results in the formations of new mRNA codons 3.Types are: insertion or deletion

Identify the category and type of mutation affecting this strand of DNA 1. AUGCCGUACCUUAUGGCUG 2. AUGC_GUACCUUAUGGCUG Write the new mRNA codons that would result. Remember: These are all gene mutations. A

Chromosomal Mutations Alterations in chromosome number and/or structure

Figure 8.23A, B Deletion Duplication Inversion Homologous chromosomes Reciprocal translocation Nonhomologous chromosomes More Chromosomal Mutations

Egg cell Sperm cell Chromosome Number – set number in a somatic cell, for example, chromosome number is 4 What will be the number in a gamete cell? This is chromosomal mutation zygote

Examples of chromosome numbers Species# of chromosomesSpecies# of chromosomes Fruit fly8Human46 Rye14Ape48 Guinea Pig16Sheep54 Dove16Horse64 edible snailsnail24Chicken78 Earthworm32Carp104 Pig40Butterflies~380 Wheat42Fern~1200

LE Key Maternal set of chromosomes Paternal set of chromosomes Possibility 1 Possibility 2 Combination 2 Combination 1 Combination 3 Combination 4 Daughter cells Metaphase II Two equally probable arrangements of chromosomes at metaphase I

LE 13-7 Homologous pair of chromosomes in diploid parent cell Interphase Homologous pair of replicated chromosomes Chromosomes replicate Meiosis I Diploid cell with replicated chromosomes Sister chromatids Meiosis II Homologous chromosomes separate Sister chromatids separate Haploid cells with replicated chromosomes Haploid cells with unreplicated chromosomes

To study human chromosomes microscopically, researchers stain and display them as a karyotype –A karyotype usually shows 22 pairs of autosomes and one pair of sex chromosomes A karyotype is a photographic inventory of an individual’s chromosomes

Preparation of a karyotype Figure 8.19 Blood culture 1 Centrifuge Packed red And white blood cells Fluid 2 Hypotonic solution 3 Fixative White Blood cells Stain 45 Centromere Sister chromatids Pair of homologous chromosomes

This karyotype shows three number 21 chromosomes An extra copy of chromosome 21 causes Down syndrome Let’s look at this Karyotype Figure 8.20A, B

The chance of having a Down syndrome child goes up with maternal age Figure 8.20C

Karyotype Lab 1.You will simulate the karyotyping task. 2.You will create a karyotype and determine the gender and developmental status of the baby. 3.You must carefully cut out all chromosomes and correctly match them up by: a.Size of chromosome b.Location of centromere c.Banding pattern on chromosome

Beginning the Karyotype

Finished Karyotype

Another Karyotype Male or Female?