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Unit Three: Sickle Cell Disease

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1 Unit Three: Sickle Cell Disease

2 3.1 Essential Questions & Key Terms
Anemia Blood Plasma Erythrocytes (Red Blood Cells) Hematocrit Leukocytes (White Blood Cells) Sickle Cell Disease Thrombocytes (Platelets) What is sickle cell disease? Why does the sickling of red blood cells cause health problems? What is sickle cell anemia? How is anemia diagnosed? How does sickle cell disease affect daily life?

3 Sickle Cell Disease Disease passed down through families
Caused by an abnormal type of hemoglobin called hemoglobin S Affects red blood cells Red blood cells (normally shaped like a disc) form an abnormal sickle/crescent shape

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5 Hemoglobin Protein Primary component of red blood cells
Composed of four sub-units Each carries one oxygen molecule People with sickle cell have abnormal hemoglobin

6 Sickle Cell Disease Sickled Red Blood Cells Deliver less oxygen
Get stuck more easily in small blood vessels Fragile- break into pieces that can interrupt healthy blood flow Decrease the amount of oxygen flowing to body tissues even more …feedback loop?

7 The Effects of SCD Millions of people throughout the world- major public health concern 3% of people with SCD die annually- sudden death More prone to blood clots Heart attacks Strokes Pulmonary embolisms Increased susceptibility to bacterial and viral infections.

8 Anemia Blood is deficient in red blood cells, in hemoglobin, or in total volume SCD often causes anemia Referred to as Sickle Cell Anemia

9 Activity 3.1.1: Blood Detectives
Anna Garcia’s autopsy report shows she had SCD You will learn the components and function of blood in order to better understand SCD and it’s impact on the body You will examine Anna’s blood with a microscope You will design an experiment to see how cell shape impacts movement You will complete a hematocrit blood test to determine whether Anna’s SCD was causing other related health problems

10 Career Journal Phlebotomist ANY format Same INFO Brochure Want-Ad
Sketch Computer Graphic Same INFO Education and/or Training Responsibilities and Daily Activities Salary Range Documentation of Sources Self-Reflection

11 Blood Plasma The pale yellow fluid portion of whole blood

12 Erythrocytes (Red Blood Cells)
Hemoglobin-containing cells that carry oxygen to tissues and take carbon dioxide back to your lungs to be exhaled Responsible for the red color of vertebrate blood

13 Leukocytes (White Blood Cells)
Colorless blood cells that lack hemoglobin and contain a nucleus: lymphocytes, monocytes, neutrophils, eosinophils, and basophils Destroy bacteria Produce antibodies against bacteria and viruses Fight malignant diseases

14 Thrombocytes (Platelets)
A minute colorless anucleate (no nucleus) disk-like body of mammalian blood Main function is to interact with clotting proteins to stop or prevent bleeding

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16 Hematocrit The percent of the volume of whole blood that is composed of red blood cells Determined by separation of red blood cells from the plasma usually by centrifugation

17 Hematocrit Results Anna’s hematocrit is approximately 30% red blood cell volume. Anything less than 35% for a female is considered a low hematocrit

18 Activity 3.1.1: Blood Detectives
Component: Function: Plasma Fluid that is composed of about 92% water, 7% vital proteins such as albumin, gamma globulin, anti-hemophilic factor, and other clotting factors, and 1% mineral salts, sugars, fats, hormones and vitamins. It is also the vehicle by which blood cells are carried around the body. Red Blood Cells (Erythrocytes) Cells that carry oxygen from the lungs to your body’s tissue and take carbon dioxide back to your lungs to be exhaled. White Blood Cells (Leukocytes) Cells that travel throughout the body and destroy bacteria, some produce antibodies against bacteria and viruses, and others help fight malignant diseases. Platelets (Thrombocytes) Small, colorless cell fragments in the blood whose main function is to interact with clotting proteins to stop or prevent bleeding.

19 3.1.2 Sickle Cell Diaries Almost every patient with SCD experiences painful episodes called crises The crises can be severe enough to require a hospital stay Anna’s doctor asked her to keep a diary documenting all of her crises In this activity you are going to investigate what life is like living with SCD…

20 3.1.2 Sickle Cell Diaries All docs are online Graphic Organizer=Table
Pick any patient 4 year old male being treated with antibiotics and folic acid supplements 7 year old female being treated with chronic transfusion therapy 15 year old male who will have a bone marrow transplant

21 3.1.2 Sickle Cell Diaries Table
Diary Entry Crisis Symptoms Benefits of Treatment Risks of Treatment Professionals Involved Lifestyle Concerns Anna 10 Anna 17 Anna 22 Anna 31 4 year old male 7 year old female 15 year old male

22 This Week! Today: Newsletters due Tomorrow Wednesday-Thursday Friday
Survival of the Sickest Presentations Notebook and portfolio checks Quiz up to slide 33 Wednesday-Thursday Community Benefit Project Friday Project Summary Due! All gifts in for Pitino Shelter Wrap Party!

23 3.1 The Disease: Review What is sickle cell disease?
Why does the sickling of red blood cells cause health problems? What is sickle cell anemia? How is anemia diagnosed? How does sickle cell disease affect daily life? Key Terms Anemia Blood Plasma Erythrocytes (Red Blood Cells) Hematocrit Leukocytes (White Blood Cells) Sickle Cell Disease Thrombocytes (Platelets)

24 Read Survival of the Sickest
This is a book about mysteries and miracles. About medicine and myth. About cold iron, red blood, and neverending ice. It’s a book about survival and creation. It’s a book that wonders why, and a book that asks why not. It’s a book in love with order and a book that craves a little chaos. Most of all, it’s a book about life—yours, ours, and that of every little living thing under the sun. About how we all got here, where we’re all going, and what we can do about it. Welcome to our magical medical mystery tour.

25 Genetic Basis for Sickle Cell Disease
Sickle Cell Link (Video) A bit on evolution….

26 What were Darwin’s Main ideas anyway???
What were Darwin’s Main ideas anyway??? Species change over time Living species have arisen from earlier life forms (descending from a common ancestor) Close ties between organisms and their environments* Can be traced back to the ancient Greeks

27 Evolution is the greatest unifying theme in biology, and The Origin of Species fueled an explosion in biological research and knowledge that continues today. Evolutionary theory continues to expand beyond Darwin’s basic ideas. Nonetheless, few contributions in all of science have explained so much, withstood as much repeated testing over the years, and stimulated as much other research as those of Darwin.

28 Natural Selection Produce more offspring than the environment can support Individuals of a population vary in their characteristics Many characteristics can be inherited Beneficial characteristics are preferentially passed down

29 Darwin found convincing evidence for his ideas in the results of artificial selection With humans playing the role of the environment Hundreds to thousands of years of breeding (artificial selection) Ancestral dog (wolf)

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34 Throughout Human Evolution
The best genes survive from one generation to next Why do we still have some deleterious genetic mutations? Various mutations have provided a benefit Extra Iron Sickle Cell We continue to see these mutations in modern day humanity even when the benefit no longer exists (leftover)

35 3.2 Essential Questions & Key Terms
Amino Acid Anticodon Codon Hydrophilic Hydrophobic Messenger RNA (mRNA) Mutation Nucleotide Protein Protein Synthesis Ribonucleic Acid (RNA) Ribosome Transcription Transfer RNA (tRNA) Translation What is the DNA code? What is the connection between genes and proteins? How are proteins produced in a cell? How does the sequence of nucleotides in DNA determine the sequence of amino acids in a protein? What is a mutation? What determines the shape of a protein? Is the shape of a protein affected by its surrounding environment? How does a change in the DNA code affect the shape of a protein? Can changing just one nucleotide in a gene change the shape of a protein?

36 Proteins What we know… DNA codes for proteins
Proteins produce all our genetic traits Responsible for just about everything our bodies do Amazingly… All the proteins we need are manufactured based on the DNA code: A,T, C and G The arrangement of nucleotides dictates everything we are genetically and runs our whole bodies because they dictate what proteins our bodies produce

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38 3.2.1 Protein Synthesis The information on DNA is copied onto an mRNA strand As, Cs, Gs and Us (in place of Ts) mRNA leaves the nucleus and moves into the cytoplasm A ribosome attaches to the mRNA tRNA molecules bring amino acids (there are 20) into the ribosome The tRNA anti-codons match the mRNA codons (3 nucleotides at a time) The ribosome assembles the amino acids into the specific protein originally coded for by the gene on the DNA

39 Transcription & Translation
Watch video

40 More on transcription…

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43 From DNA to mRNA to Amino Acid: A= A= C= G= A= T= A= C= C=
U G C A

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45 Structure of Proteins Polymers of amino acids Joined by peptide bonds

46 Activity 3.2.1 Protein Synthesis
You will explore how the body uses DNA to produce proteins

47 More on translation…

48 More on transcription…

49 Activity 3.2.2: The Genetic Code
Decode messages Transcription and translation Effect of mutations on protein production Genetic mutation that causes SCD Chose 1 to illustrate with any supplies you chose Decode the others in your lab book

50 Activity 3.2.3: Does Changing One Nucleotide Make a Big Difference?

51 Nova Documentary The sickle form of the hemoglobin gene: A is changed to a T 6th amino acid in the b-globin protein from GAG to GUG 6th amino acid in the protein to become valine instead of glutamic acid That single amino acid replacement Alters the shape and the chemistry of the hemoglobin molecule Causing it to polymerize Distort the red blood cell into the sickle shape

52 Genetic mutation to hemoglobin, causing sickle cell disease

53 Activity 3.2.3: Does Changing One Nucleotide Make a Big Difference?
Glutamic Acid: Hydrophilic or hydrophobic? ____Hydrophilic______ Positive, negative or neutral? ___Negative_______ Valine: Hydrophilic or hydrophobic? _____Hydrophobic_______ Positive, negative or neutral? ____Neutral____________

54 Protein shape dictates function! What dictates shape?
Amino acids present Charge- positive vs. negative amino acids Hydrophobic vs. hydrophilic The order of amino acids Surrounding Environment Oil Water

55 3.2 It’s in the Genes: Review
Key Terms Amino Acid Anticodon Codon Hydrophilic Hydrophobic Messenger RNA (mRNA) Mutation Nucleotide Protein Protein Synthesis Ribonucleic Acid (RNA) Ribosome Transcription Transfer RNA (tRNA) Translation What is the DNA code? What is the connection between genes and proteins? How are proteins produced in a cell? How does the sequence of nucleotides in DNA determine the sequence of amino acids in a protein? What is a mutation? What determines the shape of a protein? Is the shape of a protein affected by its surrounding environment? How does a change in the DNA code affect the shape of a protein? Can changing just one nucleotide in a gene change the shape of a protein?

56 3.3 Chromosomes How is DNA passed to new cells during cell division?
Key Terms Allele Autosome Chromosome Dominant trait Gene Genetic Material Genotype Heredity Homologous Chromosomes Karyotype Meiosis Mitosis Mutation Pedigree Phenotype Recessive Trait How is DNA passed to new cells during cell division? What is a chromosome? How are traits passed through the generations? Should a person have rights to their organs and tissues? (Optional)

57 How do you get Sickle Cell Disease?
Caused by an abnormal gene Inherited Disease E.g., Tay Sachs, hemophilia, cystic fibrosis, and Huntington’s disease Vs. Infectious (like…) How are mutations in DNA passed down from one generation to the next?

58 Activity 3.3.1: How is DNA Passed Through the Generations?
Chromosomes contain the codes for how to make specific proteins Determine the organism’s traits Chromosome Compaction Specific instructions for a protein are on sections of the chromosome called genes

59 Chromosomes DNA is stored in a compact form called chromosomes
46 chromosomes in somatic (body) cells 23 chromosomes in sex cells Egg cell from the mother fuses with the sperm cell from the father (zygote) = 46 chromosomes, 23 pairs One from mother and one from father in each pair

60 Early Zygote Nuclei from egg and sperm fusing

61 Chromosomes and Sickle Cell
Chromosome 11 carries the instructions (genes) to make the hemoglobin protein There are different versions of these genes: Normal – healthy Mutated or changed – Sickle cell or other hemoglobin disorder

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63 Mitosis (video) The chromosomes coil up
A mitotic spindle moves them to the middle of the cell The sister chromatids then separate Move to opposite poles of the cell Two nuclei form (1 at each pole) Cytokinesis, in which the cell divides in two

64 Centrosomes (with centriole pairs)
INTERPHASE PROPHASE PROMETAPHASE LM 250 Chromatin Centrosomes (with centriole pairs) Nucleolus Nuclear envelope Plasma membrane Early mitotic spindle Centrosome Centromere Chromosome, consisting of two sister chromatids Spindle microtubules Kinetochore Fragments of nuclear envelope

65 TELOPHASE&CYTOKINESIS
METAPHASE ANAPHASE TELOPHASE&CYTOKINESIS Spindle Metaphase plate Daughter chromosomes Nuclear envelope forming Cleavage furrow Nucleolus forming

66 Under the scope…

67 Meiosis (video) Meiosis, like mitosis, is preceded by chromosome duplication But in meiosis: The cell divides twice to form four daughter cells Four DIFFERENT CELLS with HALF the genetic information Half the number of chromosomes

68 The first division, meiosis I
Starts coping (sisters chromatids) and with synapsis- the pairing of homologous chromosomes In crossing over Homologous chromosomes exchange corresponding segments Meiosis I separates each homologous pair produce two daughter cells, each with one set of chromosomes Meiosis II is essentially the same as mitosis The sister chromatids of each chromosome separate The result is a total of four haploid cells

69 MEIOSIS I: Homologous chromosomes separate
INTERPHASE PROPHASE I METAPHASE I ANAPHASE I Centrosomes (with centriole pairs) Sites of crossing over Spindle Microtubules attached to kinetochore Metaphase plate Sister chromatids remain attached Nuclear envelope Chromatin Sister chromatids Tetrad Centromere (with kinetochore) Homologous chromosomes separate

70 Prophase l of Meiosis Sites of crossing over Spindle Homologous Chromosomes Tetrad: via synapsis Sister chromatids

71 Chiasma Tetrad Centromere

72 Meiosis Continued… MEIOSIS II: Sister chromatids separate
PROPHASE II METAPHASE II ANAPHASE II TELOPHASE I AND CYTOKINESIS TELOPHASE II AND CYTOKINESIS Cleavage furrow Haploid daughter cells forming Sister chromatids separate MEIOSIS II: Sister chromatids separate

73 Two equally probable arrangements of chromosomes at metaphase I
Gametes Metaphase II Two equally probable arrangements of chromosomes at metaphase I Possibility 1 Possibility 2

74 Mitosis Meiosis Parent cell (before chromosome replication) Meiosis i
Chromosomes align at the metaphase plate Tetrads align at the metaphase plate Sister chromatids separate during anaphase Homologous chromosomes separate during anaphase I; sister chromatids remain together No further chromosomal replication; sister chromatids separate during anaphase II Prophase Metaphase Anaphase Telophase Duplicated chromosome (two sister chromatids) Daughter cells of mitosis 2n Daughter cells of meiosis I n 2n = 4 Tetrad formed by synapsis of homologous chromosomes Meiosis i Meiosis ii Prophase I Metaphase I Anaphase I Telophase I Haploid n = 2 Daughter cells of meiosis II

75 What happens to chromosomes throughout? It’s all in the name…
Start as chromatin Duplicate Thicken and clump into chromosomes Consist of two sister chromatids- replicates In meiosis… Chromosomes (sister chromatid duplicates) find their other half (maternal and paternal) They make homologous pairs, forming an tetrad One chromosome carrying info from the mother, the other carrying info from the father

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77 Mutations are the original source of genetic variation
Raw material for natural selection Synapsis and crossing over during prophase Independent assortment (orientation) of homologous chromosome pairs along the metaphase plate (during metaphase) Random Fertilization of eggs by sperm

78 3.3 Chromosomes Review Key Terms Allele Autosome Chromosome Dominant trait Gene Genetic Material Genotype Heredity Homologous Chromosomes Karyotype Meiosis Mitosis Mutation Pedigree Phenotype Recessive Trait How is DNA passed to new cells during cell division? What is a chromosome? How are traits passed through the generations? Should a person have rights to their organs and tissues? (Optional)

79 3.4 Inheritance Key Terms Allele Chromosome Dominant Trait Gene
Genotype Heredity Pedigree Phenotype Punnett Square Recessive Trait Why does sickle cell disease run in families, yet is not present in every generation? How can doctors and genetic counselors calculate the probability of a child inheriting a disease? How does the presence of malaria in a region affect the frequencies of normal versus sickle cell alleles?

80 How do we know all this stuff?
Experimental genetics began in an abbey garden Father of modern genetics Gregor Mendel’s quantitative experiments Parents pass on to their offspring discrete heritable factors, which maintain individuality 7 years after Darwin’s Origins in 1859 Pea plants

81 The Humble Pea Easy to grow, came in many varieties, easy to ensure self or cross fertilization Crossed plants that differed in certain characteristics Traced traits from generation to generation P(parental generation) F1 generation F2 generation

82 Different alleles of 7 genes
Flower color Flower position Seed color Seed shape Pod color Pod shape Stem length Purple White Axial Terminal Round Wrinkled Inflated Constricted Tall Dwarf Green Yellow

83  P generation (true-breeding parents) F1 generation F2 generation
Purple flowers White flowers All plants have purple flowers Fertilization among F1 plants(F1  F1) of plants have purple flowers 3 4 of plants have white flowers 1

84 Mendel found for each characteristic…
An organism inherits two alleles, one from each parent If the two alleles of an inherited pair differ Then one determines the organism’s appearance and is called the dominant allele The other allele as no noticeable effect on the organism’s appearance and is called the recessive allele

85 Genetic makeup (alleles)
P plants Gametes Genetic makeup (alleles) F1 plants (hybrids) F2 plants PP pp All P All p All Pp Sperm 1 2 P p Pp Eggs Genotypic ratio 1 PP : 2 Pp: 1 pp Phenotypic ratio 3 purple : 1 white

86 Homologous chromosomes bear the two alleles for each characteristic
Alternative forms of a gene reside at the same locus on homologous chromosomes Homozygous recessive Homozygous dominant Heterozygous Genotype: PP aa Bb Heterozygous P a b B Gene loci Recessive allele Dominant allele Homozygous for the dominant allele Homozygous for the recessive allele

87 Back to…How do you get SCD?
It is an inherited blood disorder Both parents have to have it to pass on the abnormal gene If you inherit the problem gene from one parent and a normal gene from the other ‘Sickle cell trait' or be a Carrier Doesn't usually cause any symptoms Can be passed on to the next generation.

88 Chromosomes and Sickle Cell
Chromosome 11 carries the instructions (genes) to make the hemoglobin protein. There are different versions of these genes: Normal--healthy Mutated or changed--Sickle cell or other hemoglobin disorder.

89 3.4.1: Family Inheritance Pedigrees show the occurrence of a particular trait from one generation to the next P, F1 and F2 generations Males are represented by squares Females are represented by circles Relationships are represented with lines Make it easier to visualize relationships within families Used to determine the mode of inheritance (dominant versus recessive) of genetic diseases Pedigrees illustrate what is or has been Vs. Punnett Squares & probability (next)

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91 With two carriers= 25% Chance SCD
For every pregnancy when both parents have sickle trait, there is a 1in 4 chance that their offspring will have sickle cell anemia.

92 3.4.1: Family Inheritance & Pedigrees
How does analyzing pedigrees help doctors, epidemiologists, researchers, and other scientists understand how diseases are inherited? How are pedigrees used to track diseases? Why does sickle cell disease run in families, yet is not present in every generation?

93 Mendel’s Laws Law of Dominance Law of Segregation
In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation.  Offspring that are hybrid for a trait will have only the dominant trait in the phenotype. Dominant vs. recessive traits Law of Segregation During the formation of gametes (eggs or sperm), the two alleles responsible for a trait separate from each other.  Alleles for a trait are then "recombined" at fertilization, producing the genotype for the traits of the offspring. Which of the two alleles ends up in which gamete (monohybrid cross in Punnett square) Law of Independent Assortment The different traits do not influence the inheritance of each other.  They are inherited INDEPENDENTLY. When looking at multiple traits, alleles segregate separately (dihybrid cross in Punnett square)

94 Punnett Squares Reginald Punnett

95 A dihybrid cross! Something a bit more challenging
Uses Mendel's 3rd Law as well

96 3.4.2 What’s the Probability?
How can doctors and genetic counselors calculate the probability of a child inheriting a disease?

97 3.4.2 What’s the Probability? Punnett Squares
Create your own handout for this activity Write four word problems that require Punnett squares Be creative! Set up one question with chromosomes Use a pedigree for at least one Always ask for the genotypic and phenotypic ratio Always ask a “what’s the percent chance that..” question Be sure to have an answer key Work in 1s or 2s, but you’ll need to type and print one handout each TRADE- Due Monday! Let’s complete some examples

98 Example with chromosomes
Complete a Punnett square for these parents. Determine the genotypic and phenotypic ratios. Determine the percent chance a child has of having sickle cell anemia from this reproductive pairing

99 Example with pedigree Anna’s mother passed away three years ago, so she was unavailable for genetic testing. Based upon Anna’s family pedigree that you created in the previous activity, determine her mother’s possible genotypes and phenotypes related to sickle cell anemia. Explain your reasoning and describe the information you used to make your prediction.

100 Example word problem Juan’s family has a history of sickle cell disease. His father died of sickle cell disease complications when Juan was six years old. He remembers his father being in great pain. Juan marries Gina. Gina’s maternal grandmother and paternal grandfather had sickle cell disease, but neither of her parents has the disease. Juan does not want to have children because he is convinced they will have sickle cell disease. Gina is not so sure. They have come to you for advice about having whether or not to have children. Based on your calculations of the probability of their child getting sickle cell disease, what is your advice? Show your calculations and explain your reasoning for your response. It may be helpful for you to draw pedigrees and possible Punnett squares for both Juan’s and Gina’s families.

101 The Immortal Story of Henrietta Lacks
The first cell line, cultured more than 60 years ago The HeLa Cell-Line has been reproducing independently, fueling biological research Bioethics- The study of controversial ethics brought about by advances in biological or medical research

102 The Great Debate Two sides of the argument Prep time Henerietta’s
Dr. Gey’s Prep time Design opening and closing statement Make THREE KEY arguments Plan a defense against your opponent

103 Structure of the Great Debate
H: Opening statement (1 minutes) H: Key Point 3 (one minute) G: Opening statement (1 minutes) H: Key Point 1(one minute) G: rebuttal G: Key Point 3 (one minute) H: rebuttal G: Key Point 1(one minute) H: Closing (one minute) G: Closing (one minute) H: Key Point 2 (one minute) G: Key Point 2 (one minute)

104 3.4 Inheritance Review Key Terms Allele Chromosome Dominant Trait Gene
Why does sickle cell disease run in families, yet is not present in every generation? How can doctors and genetic counselors calculate the probability of a child inheriting a disease? How does the presence of malaria in a region affect the frequencies of normal versus sickle cell alleles? Key Terms Allele Chromosome Dominant Trait Gene Genotype Heredity Pedigree Phenotype Punnett Square Recessive Trait


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