Chapter 4: Heredity Test Review Sheet
7th Science
Vocabulary to know:
Heredity-the passage of genetic instructions form one generation to the next
Traits- the physical characteristics that are studied in genetics
Allele- the different forms of a gene
Phenotype- an organism’s physical appearance or visible traits (ex. tall stems)
Genotype- an organism’s genetic makeup (ex. Tt)
Dominant allele- an allele whose trait always shows up (ex. P)
Recessive allele- an allele whose trait can be hidden (ex. p)
Homozygous- an organism that has 2 identical alleles for a trait (ex. PP or pp)
Heterozygous- an organism that has 2 different alleles for a trait (ex. Pp)
Hybrid- an organism that has 2 different alleles for a trait (heterozygous)
Purebred- an organism that has the same form of a trait (homozygous)
Probability and Heredity
Be able to create and interpret a Punnett square for a given scenario. (Look
back at notes in ISN or Spongebob Squarepants sheets.)
Patterns of Inheritance
Codominance- occurs when both alleles for a gene are expressed equally. For
example, a chicken with black feathers FBFB and a chicken with white feathers
FWFW will have offspring that have both black and white feathers (FBFW).
Polygenetic inheritance-occurs when more than one gene affects a trait
Chromosomes and Inheritance
Chormosome theory of inheritance- genes pass from parents to their offspring on
chromosomes.
Meiosis is the process by which the number of chromosomes is reduced by half
as sex cells form. In meiosis the chromosome pairs separate and are distributed
into new sex cells.
Sexual vs Asexual Reproduction
Sexual reproduction:
Involves 2 parents
Involves joining of the sperm and egg
Different offspring of the same parents can have different characteristics
Asexual reproduction:
One parent produces a new organism identical to itself