Bio Final Exam Chapter 13
Terms
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- Explain how dominant and recessive alleles are represented on paper. State how many alleles an organism has for each trait.
- 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)
- Define probability
- 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.
- Define homozygous
- A genotype with 2 identical alleles.
- Define heterozygous
- A genotype with 2 different alleles.
- Define genotype
- Alleles represented with letters.
- Define phenotype.
- Appearance or observable characteristics.
- Define codominance.
- Codominance is when both alleles in a heterozygous organism are expressed. EX: Red flower + White flower = Pink flower (RR x rr = Rr)
- Define pedigree.
- A chart of an organism's ancestors.
- Explain which parent determines the sex of the child and why. Tell which chromosome determines maleness in humans.
- 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.
- Define multiple alleles and give an example of a trait caused by multiple alleles.
- 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.
- Name the 4 blood types.
- Type A (IAIA or IAi), Type B (IBIB or IBi), type AB (IAIB), or type O (ii.
- Explain what an X-linked (sex-linked) trait is.
- A trait whose gene is carried only on the X-chromosome.
- Name and describe 2 X-linked traits in humans.
- Red-green color blindness and hemophilia (blood disease)
- Explain the process and results of nondisjunction.
- 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.
- Give examples of abnormalities caused by disjunction.
- Turner syndrome (XO genotype), Klinefelter (XXY genotype), Down Syndrome (Trisomy 21)
- Describe the effect of crossing over on linked genes.
- Crossing over mixes up linked genes.
- Describe the genotype-environment interaction and give examples.
- 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.
- Define and identify examples of traits that are multifactorial.
- Traits that are affected by several genes and environmental factors. Examples are height, skin color, intelligence, weight, and hair color.