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18 Cards in this Set
- Front
- Back
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Explain how dominant and recessive alleles are represented on paper. State how many alleles an organism has for each trait.
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Dominant alleles are expressed as: 2 upper case or one upper and one lower. Recessive alleles are expressed with 2 lower case. An organism has 2 alleles for each trait (one from each parent)
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Define probability
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The chance that an event will occur and the number of times an event is expected to occur divided by the total number of oppurtunities for the event to occur.
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Define homozygous
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A genotype with 2 identical alleles.
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Define heterozygous
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A genotype with 2 different alleles.
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Define genotype
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Alleles represented with letters.
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Define phenotype.
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Appearance or observable characteristics.
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Define codominance.
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Codominance is when both alleles in a heterozygous organism are expressed. EX: Red flower + White flower = Pink flower (RR x rr = Rr)
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Define pedigree.
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A chart of an organism's ancestors.
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Explain which parent determines the sex of the child and why. Tell which chromosome determines maleness in humans.
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The father: the mother has 2 X chromosomes so she gives the child an X, and the father has an X and Y so the sex of the child depends on which chromosome he gives to the child. Y.
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Define multiple alleles and give an example of a trait caused by multiple alleles.
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There can be over 3 alleles for a single trait, even though no individual has more than 2. In blood, a person can have IA and IB alleles and"i" that show that the "o" trait is recessive.
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Name the 4 blood types.
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Type A (IAIA or IAi), Type B (IBIB or IBi), type AB (IAIB), or type O (ii.
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Explain what an X-linked (sex-linked) trait is.
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A trait whose gene is carried only on the X-chromosome.
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Name and describe 2 X-linked traits in humans.
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Red-green color blindness and hemophilia (blood disease)
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Explain the process and results of nondisjunction.
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THe failure of homologous chromosomes or sister chromatids to separate in meiosis. Gametes are produced by abnormal meiosis, and offspring have an unusual # of chromosomes.
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Give examples of abnormalities caused by disjunction.
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Turner syndrome (XO genotype), Klinefelter (XXY genotype), Down Syndrome (Trisomy 21)
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Describe the effect of crossing over on linked genes.
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Crossing over mixes up linked genes.
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Describe the genotype-environment interaction and give examples.
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The variations caused by hereditity and surroundings together. For example, Siamese cats. Also, nutrition and exercise interact with your genes for height and muscle size.
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Define and identify examples of traits that are multifactorial.
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Traits that are affected by several genes and environmental factors. Examples are height, skin color, intelligence, weight, and hair color.
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