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Cells and Heredity
Study Guide for Life Science
Chapter 3 – Sections 1 & 2 Quiz
Section One
Heredity – the passing of traits from parents to offspring
Trait – each different form of a characteristic
Genetics – the scientific study of heredity
Self-pollination – pollen from a flower lands on the pistil (female sex cell) of the same
flower
Cross-pollinated – when two plants are crossed
Purebred Organism – when the offspring of many generations have the same trait as the
parent – example: TT, tt
Gregor Mendel - performed two experiments on the garden pea plant
 “Father of Genetics”
Mendel’s First Experiment – crossed a purebred tall plant with a purebred short plant
first generation was all tall
Mendel’s Second Experiment –allowed the first generation tall plants to self pollinate –
second generation produced 3 tall plants and 1 short plant
Gene – the factors that control a trait
Alleles – the different forms of a gene
Dominant allele – a trait that will appear in the offspring if one of the parents contributes
it
 represented by a capital letter
Recessive allele – a trait that must be contributed by both parents in order to appear in
the offspring –
 an organism can carry the recessive trait and not show it
 is hidden whenever the dominant allele is present
 represented with a lowercase letter
Hybrid Organism – has two different alleles for a trait – example: T
Section Two
Probability – the mathematical chance that an event will occur
 written as a fraction or a percent
Punnett Square – a chart that shows all the possible combinations of alleles that can
result from a genetic cross
 can be used to determine the probability of a particular outcome
Phenotype – an organism’s physical appearance or visible traits
 ex.: brown eyes or blue eyes
Genotype – the genetic makeup or allele combination
 example: BB, Bb, bb
Homozygous – an organism that has two identical alleles for a trait
 example: TT or tt
Heterozygous – an organism that has two different alleles for a trait
 example: Tt
There will be Punnett Square problems (word problems) on the quiz. Use the examples
on the review worksheet for practice.
Quizlet review for this quiz is available at:
http://quizlet.com/67858324/mrs-weber-cms-7-cells-heredity-flash-cards/
or search "Mrs. Weber CMS 7 Cells & Heredity”
The link is also on the science 7 page on my webpage.