Human Red Blood Cells
1. Contain the protein, hemoglobin (Hb)
2. O2 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 HbDNA = CTTmRNA = GAA = Glutamic
acid-Proline-Glutamic Acid-Glutamic
Acid-
Sickle HbDNA = CATmRNA = GUA = Valine
-Proline-Valine-Glutamic Acid- This results from mutated DNA!
Base-pair substitution = replacement of one nitrogenous baseThis 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
1.
2.
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
Homologouschromosomes
Reciprocaltranslocatio
n
Nonhomologouschromosomes
Mor
e C
hrom
osom
al M
utat
ions
Eggcell
Spermcell
Chromosome Number – set number in a somatic cell, forexample, chromosome number is 4
What will be the number in a gamete cell?
This is chromosomal mutation
zygote
Examples of chromosome numbers
Species # of chromosomes
Species# of chromosomes
Fruit fly 8 Human 46
Rye 14 Ape 48
Guinea Pig 16 Sheep 54
Dove 16 Horse 64
edible snail 24 Chicken 78
Earthworm 32 Carp 104
Pig 40 Butterflies ~380
Wheat 42 Fern ~1200
LE 13-10
Key
Maternal set ofchromosomes
Paternal set ofchromosomes
Possibility 1 Possibility 2
Combination 2Combination 1 Combination 3 Combination 4
Daughtercells
Metaphase II
Two equally probablearrangements ofchromosomes at
metaphase I
LE 13-7
Homologous pairof chromosomesin diploid parent cell
Interphase
Homologous pair of replicated chromosomes
Chromosomesreplicate
Meiosis I
Diploid cell withreplicatedchromosomes
Sisterchromatids
Meiosis II
Homologouschromosomesseparate
Sister chromatidsseparate
Haploid cells withreplicated 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 redAnd white blood cells
Fluid
2
Hypotonic solution
3
Fixative
WhiteBloodcells
Stain
4 5
Centromere
Sisterchromatids
Pair of homologouschromosomes
• 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 chromosomeb. Location of centromerec. Banding pattern on chromosome
Beginning the Karyotype
Another Karyotype
Male or Female?