Understanding Mendelian Genetics

These flashcards cover key concepts of Mendelian genetics, including dominant and recessive traits, Punnett squares, and various inheritance patterns.

What are the two types of traits Mendel discovered in his experiments?

Dominant and Recessive.

What type of plants did Gregor Mendel use for his experiments?

Pea plants.

What is the male genotype for the young rat scenario discussed?

Aa.

What is the phenotype of a rat with the genotype aa?

Black.

In a Punnett Square, how do you indicate a dominant allele?

With a capital letter.

What is the genotype for homozygous dominant?

BB.

What does the term 'allele' refer to?

Different forms of a gene.

What is the physical expression of a genotype called?

Phenotype.

What genetic outcome do the letters Bb represent?

Heterozygous dominant.

What do two alleles of the same type signify in genetics?

Homozygous.

If T = tall and t = short, what phenotype does TT represent?

Tall.

What percentage of offspring would be expected to have dimples if one parent is Dd and the other is dd?

50%.

What is incomplete dominance?

When dominant and recessive traits blend in the heterozygous state.

What phenotype do blue Andalusian chicks exhibit?

A blend of black and white traits.

What does the term 'codominance' mean in genetics?

When both traits are expressed in the heterozygous condition.

What is the offspring of a tiger and lion called?

Liger.

What is a hybrid in genetics?

An offspring resulting from the mating of two different species.

Why are hybrids often sterile?

They have mismatched chromosome structures.

In Mendelian genetics, what does homozygous recessive look like?

bb.

What does the genotype Aa represent?

A heterozygous trait.

If a plant is short, what genotype could it be?

tt (homozygous recessive).

What is represented by the notation 'P' in a Punnett Square?

A dominant allele.

In Mendel's experiments, what does a dominant trait do to a recessive trait when both are present?

The dominant trait covers up the recessive trait.

How long did Mendel conduct his pea plant experiments?

Eight years.

What is the purpose of a Punnett Square?

To predict the genotype and phenotype ratios of offspring.

If a child has blue eyes (bb), what must be true about the parents' alleles?

Both parents must carry at least one recessive allele (b).

What is the term for traits that appear more frequently in a population?

Dominant traits.

What is the offspring outcome ratio for SS, Ss, and ss in guinea pigs with two short-haired parents?

¼ SS, ½ Ss, ¼ ss.

What does it mean if alleles are described as heterozygous?

They consist of two different alleles (e.g., Bb).

What is the genotype for a female rat with a black phenotype?

aa.

In the phenotype 'Tall', what would the genotype potentially be?

TT or Tt.

What traits did Mendel use that exemplify dominance and recessiveness in plants?

Tall vs. Short, Purple vs. White flowers, Yellow vs. Green peas.

What is the expected phenotype ratio of offspring in a cross between two heterozygous parents (Bb x Bb)?

3 dominant: 1 recessive.

How many boxes are in a basic Punnett Square for two traits?

Four.

What genetic principle explains why a child can have a trait that's not seen in either parent?

The action of recessive alleles.

During Mendel's time, what was the prevailing theory of inheritance before his findings?

Blending theory of inheritance.

What is meant by 'purebred' in genetics?

Organisms that are homozygous for a specific trait.

After performing a Punnett Square, how do you derive possible genotypes?

By combining the alleles of each parent.

What inheritance pattern can result in a completely new phenotype unlike either parent?

Incomplete dominance.

Can hybrid organisms reproduce successfully in natural environments?

Often no, due to sterility.

What does 'genotype' refer to?

The genetic makeup of an organism.

In the example of pea plants, what does a 'tt' genotype represent?

Short plant phenotype.

What kind of genetic trait appears in the offspring when both parents possess it?

The dominant trait.

Which type of inheritance often leads to a third phenotype appearing?

Incomplete dominance.

What crucial concept does Mendelian genetics help explain?

How traits are inherited from parents to offspring.

What characteristic of a dominant trait can generally be seen in a Punnett Square?

It appears more frequently in the resulting offspring.

Why was Gregor Mendel's work important for biology?

He laid the foundation for understanding inheritance.

In Mendelian genetics, what does the term 'allele' specifically refer to?

Each of the different forms of a gene.

What kind of traits result in a blended phenotype in offspring when a dominant and and recessive trait are present?

Incomplete dominance traits.

What is the probability of obtaining a homozygous recessive offspring when both parents are heterozygous?

25%.