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PSYB32H3 (1,174)
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Genotype.docx

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Department
Psychology
Course
PSYB32H3
Professor
Konstantine Zakzanis
Semester
Fall

Description
Genotype: the particular set of genes that a person inherits from her parents  X 2 people has exactly the same genotype  Genotype interact with the environment produced phenotype Phenotype: the observable and measurable expression of an individual’s physical and behavioral characteristics Chromosomes and Genes:  Chromosome carry genetic information that helps direct development  23 pairs: half from mom, half from dad (because chromosome is Homologous – similar in shape and function – to one of the chromosomes)  Reproductive cells contain 23 single chromosomes  Meiosis: when male’s/female’s set of chromosomes is halved to produce a germ cell (sperm, egg)mix  Crossing over: in equivalent sections of homologous chromosomes randomly switch places so that genetic information is shuffled even more  Mitosis (occur in all autosome – chromosomes that contain matching pairs – and sex chromosomes): a cell duplicates chromosomes and then divides into daughter cells that have the exact same number of chromosomes as their parent cell Genes. DNA, Proteins:  DNA: store genetic information and transmits it during reproduction o Make up of building block (nucleotide) o Each nucleotide consist a nitrogen base, a simple sugar, a phosphate group, one of the 4 different nitrogen-containing bases (adenine, thymine, cytosine, guanine o Genes: proteins of the chromosome’s DNA molecule – code for the production of certain kinds of proteins Genetic Influences on Development:  Genes never work in isolation, but always in combination with environmental influences The Transmission of Traits: A Basic Model:  The principle of segregation: each inherited trait comes from one’s parent as a separate unit  The principle of independent assortment: the inheritance of various trait occurs independently of one another  2 basic concepts of genetic chromosomes: o At any given gene’s position on 2 homologous 對應的 chromosomes, there can be more than one form of that gene (the gene’s alleles – one from mother, one from father) o If the alleles from the 2 parents are the same, the organism is homozygous 純合子 for that genes and the trait that goes with it  If A is tall, a is short (AA-tall, aa-short) o If the alleles are different, then the organism is heterozygous 雜合 子 for that characteristic  Co-dominance:  The combination of 2 dissimilar alleles will produce an outcome intermediate 中間的 btw the traits, for which each single allele codes  Both alleles will express their trait simultaneously = 2 traits will combine but not blend 混合 (Blood type: A+B=AB)  In a heterozygous combination the characteristic associated with only one of the alleles is expressed: the dominant one over the recessive allele Genes on the sew chromosomes: Exceptions to the Rule:  Sex chromosomes: one of the 23 pairs – determine the individual’s gender, and they differ in males and females  Female: XX  Male: XY  X chromosome is 5 times longer that a Y chromosomescarry more genes  X-linked genes: genes that are carries on the X chromosome and that may have no analogous 相似 genes on the Y chromosome in males  Y chromosome has no counteracting dominant genes  In female, X-linked recessive genesless frequent2 X chromosomehave a chance of inheriting a dominant and counteracting allele on the other  Hemophilia: a disorder in which the blood fails to clot nd o Hemophilia (recessive) + 2 allele inherited from other parentX code for hemophilia o If she is homozygous for recessive alleleblood clotting is impaired o If male receives the hemophilia allele on his X chromosomegreater danger of developing hemophilia o If they receives another hemophilia allele on Y chromosomes, hemophilia Modifier genes: indirectly through their effects on the expression of still other genes Genetic Disorder:  Diabetes mellitus: body’s inability to metabolize carbohydrates and maintain proper glucose levels o Heredity – multi-gene, exaggerated by environmental factors  Phenylketonuria (PKU): inability to convert phenylalanine to tyrosine; untreated, leads to mental retardation o Heredity - recessive allele  Suckle cell anemia: blood disease characterized by malfunction of red blood cells that are low in oxygen o Heredity – 2 recessive alleles in combination  Down syndrome (trisomy): physically and mentally retarded development; sometimes cardiovascular and respiratory abnormalities o Heredity – extra full/ partial chromosome 21 o Slow to learn to speak o Have difficulty articulating words and produce complex sentences in adolescence  Turner (XO) syndrome: underdeveloped secondary sex characteristics; infertility; short stature; social immaturity; webbed neck; cardiovascular and renal abnormalities (female) o Chromosomal abnormality: only 1 X chromosome o Remain short, with stubby fingers, webbed necks, unusually shaped mouths and ears o Have normal intelligence but do not develop secondary characteristics o Remain sterile  Triple X syndrome: some physical abnormalities, including menstrual irregularities and premature menopause; some limitations on cognitive abilities (female) o Chromosomal abnormality: extra X o Normal physical and secondary characteristics o Cognitive ability deficit: short-term memory, verbal skills  Klinefelter’s (XXY) syndrome: some female physical characteristics, sterility; mild to severe cognitive difficulties (male) o Chromosomal abnormality: extra X o Sterile, have female characteristic, have verbal language deficit, reading problems, memory, reasoning problems, inhibitory skills  XYY syndrome: unusual height; some cognitive impairment attention deficit o Chromosomal abnormality: extra Y o Cognitive impairment o Generally taller than normal man o Show no more aggression than normal man  Fragile X syndrome: physical abnormalities; mental retardation that deepens with time; psychological and soc
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