Name: _________________________________________ Sec: ____________ Date: ____________
Chapter 3 – Heredity Study Guide
Section 1 – Mendel and his Peas
___________– the passing of genetic traits from parent to offspring
__________________ – scientist born in Austria, studied pea plants at a monastery
________________ – plants that have both male and female reproductive structures. The pollen from
one flower can fertilize the ovule of the same flower or the ovule of another flower on the same plant.
______________________ – all the offspring have the same traits as the parents.
_____________________– pollen from one plant fertilize the ovule of a flower on a different plant.
This happens in different ways:
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Pollen can be carried by __________
Pollen can be carried by the _______________
Human intervention
___________________ – a feature that has different forms in a population: ex. Hair color, eye color
________________ – the different forms of characteristic; example: black hair, blonde hair, blue eyes,
brown eyes
Mendel’s first experiments:
________________________ – a trait that appears in the first generation when parents with
different traits are bred
_________________________- – a trait that reappears in the second generation after
disappearing in the first generation when parents with different traits are bred
Mendel determined that each plant had two sets of __________________- for each characteristic.
Mendel’s research opened the door to modern ___________________.
Section 2 – Traits and Inheritance
_______________ – the one set of instructions for an inherited trait. The offspring has two forms of the
same gene for every characteristic; one from each parent.
_______________ – different forms of the genes. Dominant alleles are represented with upper case
letters, example brown hair BB. Recessive traits are represented with lower case letters, example
blonde hair bb.
______________ – the physical appearance of an organism. Example: purple flower, white flower,
yellow flower
___________________ – the genetic makeup of an organism or combination of genes for one or more
traits. Example: Purple flower PP or Pp
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_____________________ (same) – a gene with two dominant or two recessive traits. Examples:
PP or pp
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___________________ (different) – a gene with one dominant and one recessive allele.
Example: Pp or Bb
_____________
___________ – used to organize all the possible combinations of offspring from
particular parents.
Exceptions to Mendel’s principles:
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Incomplete dominance/ codominance – ______________________________________.
Example: snapdragon flower
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One gene, many traits – _________________________________. Example: the white tiger’s fur
color and eyes are influenced by the same gene.
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Many genes, one trait – _________________________________________. Examples: different
combinations of alleles result in different eye color shades.
Section 3 – Meiosis
_______________ __________________– chromosomes that have the same sequence of genes and
have the same structure.
______ _______________________ – one of the pair of chromosomes that determine the gender of an
individual. Females have two X chromosomes; XX, and males have one X and one Y chromosome; XY.
____________ _____________ _______________ – certain disorders that are associated with the
gender of an individual. The gene is recessive, therefore, males are more likely to have sex-linked
disorders because they only have one X chromosome, whereas females have two. Examples: color
blindness and hemophilia
________________ – a diagram made by a genetic counselor that shows the occurrence of a genetic
trait in many family generations.
_______________ ________________ – organisms with desirable characteristics are mated to form
offspring. Examples: chickens bred to produce larger eggs, roses bred to produce larger flowers.