GENETICS BASICS

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%

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)

Think-Pair-Share

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

Think-Pair-Share

Why do organisms have two
alleles for every trait?