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Lecture

Biological beginnings.docx

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Department
Biology
Course
BIOL 2020
Professor
billpohajdak
Semester
Winter

Description
Chapter 3: Biological beginning LOOK ON OWL FOR SLIDE ON CHARLES DARWIN AND TREE OF LIFE Natural selection: Evolutionary process that favours individuals of a species that are best adapted to survive and reproduce Charles Darwin: 1809-1882 Arthropod, molluscs, chorda Picia: Weak physical characteristics Strategies used for survival Importance was not developing new skin or a new shell but rather developing strategies that help with survival LOOK ON OWL FOR EVOLUTION OF VERTEBRATE BRAIN AND GRAPH ON BRAIN SIZES OF HUMANS AND PRIMATES Evolutionary psychology Emphasizes adaptation, reproduction, and "survival of the fittest" in shaping behaviour Evolutionary developmental psychology Evaluating evolutionary psychology Evolution does not dictate behaviour Biology allows broad range of possibilities Human development One cell --> A fetus consisting of 6 trillion cells (at birth) (SLIDE ON OWL) Cytoplasm: Outer area - generates product for growth and functioning Nucleus: core Chromosomes: composed of genes (code) Blueprint of individual's development A threadlike structure made up of 1000's of genes There are 46 chromosomes in the cell nucleus Organized into 23 pairs Each pair (one from the father and one from the mother) Genes: Basic unit of heredity Made up of DNA (deoxyribonucleic acid) Genes act as pairs Located on the same site on a chromosome pair DNA is translated to RNA and finally a protein is made (SLIDE ON OWL) Mutations: abnormality at any stage of translation produces abnormal protein Once it occurs, mutations are apart of a person's genetic code Mutations Point mutation: Caused by a single base pair Outcomes No adverse effect via protein Missense: error in protein Phenylketonuria (PKU): error in producing enzyme to breakdown phenylalanine Nonsense: No protein formed Protein neurofibromin (a tumor suppressor) is not formed LOOK ON OWL FOR NEUROFIBROMATOSIS TYPE 1 (NF-1) Defect on chromosome 17 Study tip Make a table of the disorders (in class and textbook) -- 4 columns Name of disorder Chromosome affected Type of error (if known) Characteristics of disorder January 30th (Lecture 8) (LOOK ON OWL) Of the 23 chromosomes, 22 (called autosomes) are similar in males and females Sex is determined by the 23rd pair, the sex chromosome Male child has an X and a Y chromosome (XY) Female child has 2 X chromosomes (XX) Abnormality inn 22 pairs of chromosomes (called autosomes) Autosomal disorder Abnormality on the 23rd pair, the sex chromosome Sex-linked (X-linked) disorder Genetic process Fertilization: Sperm penetrates ovum Sperm releases genetic material (23 chromosomes) Nucleus of the ovum releases its own genetic material (23 chromosomes) A new cell (zygote) is created from the genetic material and this is the beginning of a human being Cell division: Mitosis (all cells - except sperm and egg) meiosis (germ cells - egg and sperm) MITOSIS AND MEIOSIS SLIDES ON OWL Chromosomal abnormalities Nondisjunction: Unequal chromosomes or chromatids During cell division of a daughter cell: Daughter cell 1: 47 chromosomes (trisomy) Daughter cell 2: 45 chromosomes (monosomy) OR Daughter cell 1: 0 chromosomes Daughter cell 2: 92 chromosomes (tetraploidy) Spontaneous abortion when cells have less than 46 chromosomes Nondisjunction is more common during meiosis (sperm or ova does not have exactly 23 chromosomes) Down syndrome (Trisomy 21): 21st chromosome site has 3 instead of 2 Child receives 3 rather than 2 (21st) chromosomes 90% cases during nondisjunction during meiosis of egg (24 chromosomes) - mother is usually older - 90% due to mother 5% cases meiosis of sperm (24 chromosomes) - 5% due to father 5% cases of Down syndrome occurs from mitosis of the embryo (mosaicism - not just for down syndrome) Males with down syndrome are sterile but if they are mosaic they could father a child Down syndrome like features (mosaicism) Features correlated to when chromosome abnormality occurred during cell division Normal (46 chromosome) cells mixed with abnormal cells (47 chromosomes) --> mixture of cells Neurofibromatosis type 1 chromosome 17 affected nonsense (no protein) Characteristics: tumor at nerve endings Nondisjunction of autosomes Trisomy 21 Trisomy 13, 18 (severe cognitive impairments) Trisomy 16 (no reported live birth) Down syndrome Chromosome 21 affected Extra chromosome Characteristics: Short neck, small head, 1 crease (lines) on palms, short stature Trisomy 18: Edwards syndrom Chromosome 18 Extra chromosome on 18th site Characteristics: Distinct finger grasping pattern (middle finger elongated), rocker- bottom feet (curvature on the feet), intellectual impairment Trisomy 13: patau syndrome Chromosome 13 affected Extra chromosome Characteristics: Microcephaly (small head), cleft lip/palate, short neck, polydactyly (extra digits) Trisomy 16 Chromosome 16 affected Extra chromosome No live birth Triploidy syndrome Triploidy: Extra chromosome in each pair Most die within 2 months of life Incidence: 1/2,500 births 69, XXY (60%) 69, XXX (37%) 69, XYY (Less than 3%) Diploidy/triploidy mosaicism Milder phenotype We are all diploidy Characteristics: "Cracked egg-shell" skull (thin skull), beaked nose, small chin, low-set /malformed ears, woolly hair, syndactyly of fingers (3-4 fingers), syndactyly of toes (3-4) Nondisjunction of sex chromosomes (23rd pair) XY - male XX - female Klinefelter syndrome (47, XXY) 23rd chromosome affected Extra X chromosome (XXY) - can come from mother or father Characteristics: Tall, slender, enlarged breasts (male), long arms and legs, small genitalia, inability to produce sperm 80%-90% have 47, XXY About 10% of patients have mosaicism Turner syndrome (45, X) (monosomy X) Only have 1 chromosome on the 23rd chromosome site A female with a single X chromosome in each cell (XO) Error is missing X-chromosome Non-dysjunction 99% are spontaneously aborted 80% cases due to cell division errors in father Characteristics: Very short, webbed neck, nonfunctional ovaries, visual-perceptual impairment, average intelligence Deletion i.e. "cat-cry" syndrome (cri-du-chat) Deletion of the short arms of chromosome 5 NOT nondisjunction -- DELETION Characteristics: Round face, low set ears, widely-spaced eyes, mental retardation, microcephaly (small head), high-pitched cry Angelman syndrome (AS): is an uncommon neurogenic disorder characterized by mental retardation, abnormal gait, speech impairment, seizures, and an inappropriate happy demeanour that includes frequent laughing, smiling, and excitability. The uncoordinated gait and laugher have caused some people to refer to this disorder as the "happy puppet" syndrome The genetic basis of AS is very complex, but the majority of cases are due to a deletion of segment 15q11-q13 on the maternally derived chromosome 15 Chromosome 15 Maternal chromosome has a flaw If error came from father on chromosome 15 then its a totally different syndrome Prader-Willi syndrome (PWS): is an uncommon inherited disorder characterized by mental retardation, decreased muscle tone, short stature, emotional lability and an insatiable appetite which can lead to life- threatening obesity Comes from the father - chromosome 15 Cockayne syndrome: Chromosome 5 error (genetic error) - deletion (missing a set of genes) Characteristics: rapid aging DiGeorge syndrome Chromosome 22 (deletion) Missing a large portion of chromosome 22 Characteristics: As a result they develop recurrent infections and heart problems William's syndrome Recessive disorder Chromosome 7 (genetic disorder) 20 genes are missing on chromosome 7 Characteristics: Have a higher ability for things like music, math (right hemisphere- orientated things), very happy and sociable, great sociability, intellectual impairment Werner's syndrome Chromosome 8 Deletion of genes Characteristics: causes individual to rapidly age Question 3 (A) Mechanisms of inheritance Gregor Mendel (1822-1884) Single gene-pair inheritance Human characteristics that are influenced by only one pair of genes (alleles) MY FAMJAM: Mom has blue eyes, dad has brown eyes, me and brook have brown eyes (blue = recessive) Dominant gene and recessive gene (you can carry the effect and may not be expressed) Example (hair color - brown being dominant and blond being recessive) Mother (Bb) Father (Bb) DO PUNNETT SQUARE TO SEE OFFSPRING 3/4 of offspring will have brown hair and 1/4 of offspring will have blonde hair BB, bb, Bb (x2) Homozygous pair: both genes are dominant or both genes are recessive Heterozygous pair: One dominant and one recessive gene - dominant overrides the recessive (don't really worry about codominance) LOOK AT GENETICS NOTES TO HELP February 4th (Lecture 9) Questions pertaining to assignment 1 Question 1: Biological --> genetics and physical development (when you hit puberty -- early bloomer --- 4 possible things - only one that has a benefit is males that mature early) Sources -- facts from video, Clinton biography, facts from the book Family tree -- Put in appendix section (figure 1 in appendix A) or simply combine it in the text Mendelian disorders Autosomal recessive (1700 Mendelian disorders we know of now): abnormal gene (recessive) from both parents Two recessive genes required for disorder i.e. Tay-Sachs: On chromosome 15. Error is 2 recessive genes Brain damage and early death (before age 5) -- slow death until the suffocate and die Mother Tt Father Tt Child = 25% probability of having a child with Tay-Sachs problem: Lack of enzyme to break town fatty substance in brain and nerve cells The ongoing accumulation of lipids in nerve cells, resulting from the missing or defecting Hex A enzyme, causes progressive damage The destructive process begins in the fetus early in pregnancy A baby appears normal until about 6 months of age By about 2 years old, recurrent seizures etc.. (LOOK IN OWL) Autosomal dominant (4500 Mendelian disorders) No such thing as a carrier, you have it or you don;t Cause by single dominant (abnormal gene) Huntington's disease: On chromosome 4 Deterioration of nervous system - slurred speech Erratic walk, jerky movements, facial grimaces Dementia Marfan syndrome: Chromosome 15 Autosomal dominant disorder Tall stature, where your armspan are greater than you height Achondroplasia: Chromosome 4 Short stature dwarfism sex-linked inheritance The genes are located on the X sex chromosome (225 X-linked disorders are known) Muscular dystrophy (X-linked recessive pattern Fragile X syndrom 23rd X-chromosome Mental retardation Hemophilia Colour bindles 23rd x-Chromosome Blood disorder Hereditary bleeding disorder Low levels or complete absence of a blood protein essential for clotting x-linked disorders are more common among males Females can have the disorder if X-linked dominant disorder Lyonization: Unequal activation of X- chromosome Females with monosome OX (turners syndrome) If they get an X chromosome from the mother and the father (for recessive X-linked trait) Coffin-Lowry syndrome A rare genetic disorder characterized by caniofacial (head and facial) and skeletal abnormalities, mental retardation, short stature, and hypotonia Chromosome 23 Incontinentia Pigmenti: a condition affecting many body systems, particularly the skin. This disorder is characterized by blistering and warlike skin growths in early childhood followed by changes in s
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