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

Finished Karyotype

Another Karyotype

Male or Female?