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18 Cards in this Set

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  • Back
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.