Biology 1B
Chapters 11 and 14
1. Define heredity and identify the units of
heredity.
2. Discuss the design, results and
conclusions of Mendel’s monohybrid
cross experiment.
3. Explain the principle of dominance and
the principle of segregation
 From the same root word as “inherit”
 Heredity describes the passing of traits from
parents to offspring
 Give examples of traits shared with family
members:
 How are traits
passed from
parents to
offspring?
 Many children resemble an aunt, uncle or grandparent
more than they do their parents.
 Some traits seem to “skip generations”
 Often traits are expressed in children that are not
observed in any other family member
 ANY ACCEPTABLE HYPOTHESIS SHOULD BE ABLE
TO ACCOUNT FOR THESE OBSERVATIONS
 Traits are inherited from
only one parent
 This seems true in many
cases, because many
children have a strong
resemblance to either
their mother or their
father
 Traits are inherited from
both parents
 This seems true in many
cases also, because
many children resemble
both parents, and often
have one trait similar to
their father and another
trait similar to their
mother
 Mendel was an Austrian
monk in the mid 1800’s
 Monks make
contemplation and study
a lifestyle.
 Life at the monastery is
largely self-sufficient. It
is common for Monks to
grow their own food.
 Mendel grew peas for
food at the monastery,
and observed that the
pea plants had a variety
of distinct traits, such as
flower color, that
appeared to be inherited
traits.
 Mono = one
 Hybrid = cross breed
 Mendel picked one trait at a time (“mono”) for his
experiments, and cross bred (“hybrid”) pea plants for
each trait to see what would happen
 To track the effect of inheritance from one parent
compared to the other, the parents must be different
with regard to the trait being studied (“hybrid”)
 The first generation in the experiment is labeled “P1”
 P for Parents, 1 for 1st generation
• This is a “hybrid” cross, because the parents are
different for the trait being studied.
• What trait is being examined in this experiment?
 F1, F for filial (greek for
brothers) and 1 for 1st
generation
 In a cross between one
purple flower parent and
one white flower parent,
all the offspring had
purple flowers.
 What hypothesis does
this support?
4. Use punnett squares to predict the
probability of genetic crosses
5. Discuss the design, results and
conclusions of Mendel’s dihybrid cross
experiment.
6. Explain the principle Independent
Assortment
7. Explain the following forms of inheritance:

Incomplete dominance
 Codominance
 Multiple alleles
 Polygenic inheritance
8. Use pedigrees to analyze inheritance of
alleles within families
9. Explain ABO blood type and Rh factor, and
explain the inheritance of both traits
10. Define the terms haploid and diploid. Relate the terms
to the life cycle of plants and animals.
11. Describe the process of meiosis.
12. Explain what is happening in each stage of meiosis
13. Use the chromosome theory to contrast between
“linked” genes and those inherited by independent
assortment
14. Compare and contrast mitosis and meiosis