GENETICS BASICS

GENETICS: Heredity & INHERITANCE
Essential Question: How can the traits of
offspring be accurately predicted based
on the traits of their parents?

BELLWORK: _________
Explain: _____________________________

Life Science – Genetics: Heredity & Inheritance

Learning Intention
Today I’m reviewing about
how traits are passed from
parents to offspring.

Success Criteria

• Define vocabulary and identify

the location of your DNA.

• I can use Punnett squares to

accurately predict the
probability of inheritance

•

I can accomplish 80% or better
on my PENDA assignments

Bellwork
The gene for curled ears is dominant over the gene for straight ears
(e). If you crossed a cat with curled ears (Ee) and a cat with straight
ears (ee), what percent of the offspring are expected to have curled
ears?

A. 100%
B. 75%
C. 50%
D. 25%

Open Ended

The gene for curled ears is dominant over the gene for straight ears (e). If you crossed a cat with curled ears (Ee) and a cat with straight ears (ee), what percent of the offspring are expected to have curled ears?

A. 100% B.  75% C. 50% D. 25%

Choose the letter of your answer and explain why.

GENETICS: Heredity & INHERITANCE
Essential Question: How can the traits of
offspring be accurately predicted based
on the traits of their parents?

Cell: The basic unit of life. La unidad básica de la vida.

Chromosomes: A collection of DNA wound up like Christmas
lights. Una gran colección de ADN terminó como luces
navideñas.
○Genes: Segments of DNA that give instructions for a specific

trait (eye color). Segmentos de ADN que dan instrucciones
para un rasgo específico (color de ojos).

○DNA: A large molecule that carries codes for all your traits.

Una molécula grande que lleva códigos para todos tus
rasgos.

DRAWING/EXAMPLE:

Combinations of Alleles

○ Dominant: an allele that is

always expressed when
present. “Visible”

○ Recessive: An allele that is

only expressed if the
dominant is NOT present.
(not visible”) Can only be
seen when both alleles are
recessive.

Punnett Square
Vocabulary

○Genotype: The combination

of alleles that an organism
carries for a certain trait.
(Bb) “CODE”

○Phenotype: What we can

observe in organisms. The
RESULT of the genotype.
(Brown eyes) “PHYSICAL
APPEARANCE”

Combinations of Alleles

○ Homozygous : Same pairs of alleles

Homozygous DOMINANT: a genotype where both alleles are
dominant. (BB)

○ Homozygous RECESSIVE: a genotype

where both alleles are recessive (bb)

○ Heterozygous: a genotype where a

person has one dominant and one
recessive allele, only the dominant
allele is expressed. (Bb)

Open Ended

Is it possible for someone to have blue eyes while their parents both have brown eyes? Explain why or why not.

Think-Pair-Share

Is it possible for someone to have
blue eyes while their parents both
have brown eyes? Explain why or
why not.

Open Ended

Why do organisms have two alleles for every trait?

Think-Pair-Share

Why do organisms have two
alleles for every trait?

Multiple Choice

The gene for curled ears is dominant over the gene for straight ears (e). If you crossed a cat with curled ears (Ee) and a cat with straight ears (ee), what percent of the offspring are expected to have curled ears?

• A. 100%

• B.  75%

• C. 50%

• D. 25%