Genetics Review

​Genetics - Punnett Squares Review

What is Genetics?

Genetics is the study of heredity, which is the passing of traits from one generation to another.

Are a sequence in DNA that code for a protein, thus for a specific traits

​

Genes

Alleles are different possibilities for a given trait!

• Every trait has two alleles. One from mother and one from father.

• Ex: blue/black eyes, brown/blonde hair, tall/short

​Alleles?

Traits are specific characteristics that varies from one individual to another.

• Blue eyes

• Brown hair

• Tall

Traits?

What is the difference between Traits and alleles?

Multiple Choice

In pea plants, the tall allele is dominant to the short allele. What key would demonstrate this?

• Tall = T

  Short = S

• Tall = t

  Short = T

• Tall = T

  Short = t

• Tall = TT

  Short = tt

An organism with a recessive allele combination will only exhibit that trait when the dominant allele isn't present.

• Represented by a lowercase letter "r"

Recessive

Is stronger so it masks the other trait if present.

• Represented by a capital letter "R"

Dominant

Dominant vs recessive

Multiple Choice

Identify the homozygous dominant genotype:

• FF

• Ff

• ff

Multiple Choice

What are genes?

• Something you wear

• The powerhouse of cells.

• Segments of DNA that carry traits for offspring.

• None of the answers are right

​Genotypes vs Phenotypes

Genotype: The genetic makeup of an organism. The gene (or allele) combination an organism has.

• Examples: Tt, SS, Bb, aa

Phenotype: The physical characteristics of an organism

• Examples: Tall or short, Straight hair or wavy hair...

Multiple Choice

Which of the following is an example of phenotype?

• bb

• blue eyes

Homozygous vs Heterozygous

Homozygous - Term used to refer to an organism that has two IDENTICAL alleles for a particular trait. Considered as purebred! EXAMPLE: TT or tt

Heterozygous - Term used to refer to an organism that has two DIFFERENT alleles for a particular trait. Considered as hybrids.

EXAMPLE: Tt

Multiple Choice

Which of the following genotypes are purebred?

• Pf

• Bb

• BB

• pF

Multiple Choice

Which of these is homozygous recessive?

• Rr

• RR

• Ba

• bb

Multiple Choice

An organism's physical appearance or visible traits. (what it looks like)

• phenotype

• genotype

Multiple Choice

What allele combination should go in the missing box?

• aa

• AA

• Aa

• None

Multiple Choice

What is the phenotype of the offspring? (A-Brown hair; a-blond hair) 

• 50 % Brown Hair and 50% Blond Hair 

• 75 % Brown Hair and 25% Blond Hair 

• 25 % Brown Hair and 75% Blond Hair 

• 0% Brown Hair and 100% Blond Hair 

Multiple Choice

Which of the following genotypes is heterozygous?

• GG

• hh

• T

• Aa

Match

Match the following.

• genes are the same

• genes are different

• T - tall

• t - short

• the study of heredity

homozygous

heterozygous

dominant allele

recessive allele

genetics

• homozygous

• heterozygous

• dominant allele

• recessive allele

• genetics

Match

Match the following

• homozygous dominant genes

• heterozygous dominant genes

• homozygous recessive genes

• genetic material of an orgnism (DNA)

• physical characteristics of an organism

AA

Hh

bb

genotype

phenotype

• AA

• Hh

• bb

• genotype

• phenotype