Download Punnett square

Bellwork:
Create a 18 word paragraph
explaining how MEIOSIS relates
to HEREDITY.
Turn it in.
Content Objective: I will
understand and predict genetic
outcomes using a Punnett Square
Language Objective: I willwrite
notes. I will answer questions by
writing Punnett Squares with a
partner.
Who is Gregor Mendel?
A trait is a specific characteristic that varies
from one individual to another. Example…
Biological inheritance is
determined by factors that
are passed from one
generation to the next.
The chemical factors that
determine traits are called
genes.
The different forms of a
gene are called alleles.
The principle of
dominance states that
some alleles are
dominant while others
are recessive.
The dominant allele will
always be expressed.
A capital letter is used to
represent a dominant
allele.
The recessive allele will only
be expressed (phenotype)
when the dominant allele
for the trait is not present.
A lower case letter is used
to represent a recessive
allele.
A phenotype is an
organism’s physical
characteristics.
A genotype is an
organism’s genetic
makeup.
Two organisms can
have the same
phenotype but
different genotypes.
Example…
Organisms that have two of the
same alleles for a trait are
homozygous.
Organisms that have two
different alleles for a trait are
heterozygous.
Homozygous organisms are
true-breeding for a trait.
Heterozygous organisms are
hybrid for a trait.
The way in which alleles separate during meiosis is
completely random. This is also known as the principle of
independent assortment.
The results of genetic
crosses can be
explained by
probability.
Probability is the
likelihood that a
particular event will
occur.
The gene combinations
that might result from a
genetic cross can be
determined by drawing a
diagram known as a
Punnett square.
The letters in the Punnett
square represent alleles.
Punnett squares are used
to predict and compare
the genetic variations
that will result from a
cross.
Punnett Square practice…
1. What would be the possible outcomes for the offspring of a
cross between pink flower (PP) and a white flower (pp)?
2. Long fingers are dominant (F) to short fingers (f).
Complete the Punnett square for a homozygous
recessive mom and a heterozygous dominant dad.
3. In a plant, long stems are dominant (L) to short stems (l). If a
homozygous dominant flower and a homozygous recessive plant are
crossed, what would be the phenotypic ratio of their offspring?
4. Straight hair (C) is dominant to curly hair (c). What would
be the probability that a child would have curly hair if both
parents are heterozygous dominant?
5. Having a hitchhiker's thumb is a dominant trait. If a
woman with a straight thumb has a child with a man
who is heterozygous for the trait, what are the chances
their child will have a hitchhiker's thumb?
6. What would the phenotypic and genotypic ratios be
for two purple (Pp) flowers that were bred together?
7. If being right handed is a dominant trait, then how many
right handed children would two left handed parents have?
Summary: In 35 words summarize your
understanding of genetics. Be sure to
use the words allele, dominant,
phenotype