Fast and Curious: Patterns of Inheritance

What is the term used to describe an allele that masks the effect of another allele?

• Recessive

• Dominant

• Genotype

• Phenotype

Answer explanation

The term 'dominant' refers to an allele that can mask the effect of another allele, known as a recessive allele. In a heterozygous genotype, the dominant allele's trait is expressed, while the recessive allele's effect is hidden.

The genetic makeup of an organism?

• Phenotype

• Genotype

• Allele

• Carrier

Answer explanation

The genetic makeup of an organism is referred to as its genotype. It encompasses all the alleles an organism carries, distinguishing it from phenotype, which is the observable traits.

What is a Punnett square used for?

• To determine the physical appearance of an organism

• To predict the probability of certain traits in offspring

• To identify the number of chromosomes in a cell

• To measure the size of an organism

Answer explanation

A Punnett square is a tool used in genetics to predict the probability of certain traits in offspring by showing the possible combinations of alleles from the parents.

When an organism carries two identical alleles for a trait (BB or bb)

• Heterozygous

• Homozygous

• Carrier

• Dihybrid

Answer explanation

When an organism has two identical alleles for a trait, such as BB or bb, it is referred to as homozygous. This contrasts with heterozygous, where the alleles are different.

When an organism that carries two different alleles for a trait?

• Homozygous

• Heterozygous

• Purebred

• Recessive

Answer explanation

An organism with two different alleles for a trait is called heterozygous. In contrast, homozygous refers to having two identical alleles. Purebred indicates a lineage with consistent traits, while recessive describes an allele that is masked by a dominant one.

Which of the following describes a monohybrid cross?

• A cross involving two traits

• A cross involving one trait

• A cross involving three traits

• A cross involving four traits

Answer explanation

A monohybrid cross involves a single trait, examining the inheritance of one characteristic. This distinguishes it from dihybrid or polyhybrid crosses, which involve two or more traits.

What is a dihybrid cross?

• A genetic cross involving one trait

• A genetic cross involving two traits

• A genetic cross involving three traits

• A genetic cross involving four traits

Answer explanation

A dihybrid cross examines the inheritance of two traits simultaneously, making the correct choice 'A genetic cross involving two traits'. This contrasts with monohybrid crosses, which involve only one trait.

The physical appearance of an organism?

• Genotype

• Phenotype

• Allele

• Carrier

Answer explanation

The physical appearance of an organism is referred to as its phenotype. This term encompasses all observable traits, distinguishing it from genotype, which refers to the genetic makeup.

What is a carrier in genetic terms?

• An organism with two dominant alleles

• An organism with two recessive alleles

• An organism that has one recessive allele for a trait but does not express it

• An organism that expresses a recessive trait

Answer explanation

A carrier is an organism that has one recessive allele for a trait but does not express it. This means they can pass the recessive allele to offspring without showing the trait themselves.

What does it mean if an organism is purebred?

• It has two different alleles for a trait

• It has two identical alleles for a trait

• It has one dominant and one recessive allele

• It is a carrier for a trait

Answer explanation

A purebred organism has two identical alleles for a trait, meaning both alleles are the same, whether they are dominant or recessive. This is why the correct answer is that it has two identical alleles for a trait.