Genetics Unit Test Review

TRAITS

Families have things in common because traits are passed

from our parents, to us

Eye Color
Hair Color
Skin Color

Body Shape

GENETICS

The study of how traits are inherited through the inheritance

of genes. What genes do we get from who?

The material that controls what we look like (our traits)

Genes are found inside chromosomes

We receive one of each gene from our parents

Eye color gene: one from mom, one from dad
Hair color gene: one from mom, one from dad

WHAT IS A GENE?

GENES

Half from your mom

Half from your dad

INHERITED TRAITS

Characteristic

controlled by a gene

made up of DNA

Curly Hair

Attached Earlobes

Freckles

Allergies

Our genes decide if
our hair will be curly

or straight. This

information comes
from our parents.

ACQUIRED TRAITS

Characteristic

learned or obtained

from the

environment

Languages

Attitude

Dyed Hair

Handedness

Punnett
Square

WHAT IS IT?

The Punnett square is a diagram that is used to predict
an outcome of a particular cross or breeding
experiment.

It is named after Reginald C. Punnett, who devised the
approach. The diagram is used by biologists to determine
the probability of an offspring having a
particular genotype.

WHAT DOES IT LOOK LIKE?

WHAT IS IT?

The Punnett square is a diagram that is used to predict
an outcome of a particular cross or breeding
experiment.

It is named after Reginald C. Punnett, who devised the
approach. The diagram is used by biologists to determine
the probability of an offspring having a
particular genotype.

REMEMBER GENES?

Genes tell us what we will look like, they are inside chromosomes

Curly Hair?

Blue Eyes?

Long Legs?

Brown Hair?

ALLELE

Alleles are different combinations of a gene

Allele Pairs

BB

Homozygous

bb

Homozygous

Bb

Heterozygous

DOMINANT VS RECESSIVE

Recessive: Overpowered if
there is a dominant gene
present

Dominant: Overpowers all
other genes

a

a

A

Aa

Aa

A

Aa

Aa

HOMOZYGOUS

The SAME genes, BOTH dominant or BOTH recessive

B

B

B
BB

BB

B
BB

BB

b

b

b
bb

bb

b
bb

bb

HETEROZYGOUS

BOTH dominant AND recessive genes

a

a

A
Aa

Aa

A
Aa

Aa