PowerPoint #1 - Chapter 12 Mendel's Experiments and Heredity

Who is considered the father of genetics?

Johann Gregor Mendel

What type of plants did Mendel cross in his flower color experiment?

True-breeding plants for violet and white flower colors

What was the phenotype of the F1 generation in Mendel's flower color experiment?

All had violet flowers

What was the approximate ratio of violet to white flowers in the F2 generation?

Approximately 3:1 (three quarters violet, one quarter white)

What is the result of crossing true-breeding yellow and green pea plants?

F1 heterozygotes with a yellow phenotype

What analysis can be used to predict genotypes in Mendel's experiments?

Punnett square analysis

What is a test cross used for?

To determine if an organism expressing a dominant trait is a homozygote or heterozygote

What is alkaptonuria?

A recessive genetic disorder affecting the metabolism of phenylalanine and tyrosine

What are the symptoms of alkaptonuria?

Darkened skin, brown urine, joint damage, and other complications

How can a child's genotype indicate the genotypes of their parents?

If neither parent has the disorder but their child does, the parents must be heterozygous

What is incomplete dominance as illustrated by snapdragons?

A heterozygote results in a phenotype that is a blend of the two homozygous phenotypes, such as pink flowers

How many different alleles exist for the rabbit coat color gene?

Four different alleles

What is the significance of the Antennapedia mutant in Drosophila?

It has legs on its head instead of antennae, illustrating a genetic mutation

What role does the Anopheles gambiae mosquito play in disease transmission?

It acts as a vector for the malaria-causing parasite

What is the name of the parasite transmitted by Anopheles gambiae?

Plasmodium falciparum

What determines eye color in Drosophila?

Several genes, including those for white and vermilion eye colors located on the X chromosome.

What is the wild-type eye color in Drosophila?

Red eye color, which is dominant to white eye color.

What is a Punnett square used for?

To determine the ratio of offspring from a genetic cross.

What is the chance that a son of a carrier of a recessive X-linked disorder will be affected?

50 percent.

What is the probability that a daughter of a carrier of a recessive X-linked disorder will be a carrier?

50 percent.

What characterizes Huntington's disease at the cellular level?

Nuclear inclusions characteristic of the disease are present in neurons.

What type of trait is albinism?

A recessive trait.

What method can be used to analyze a trihybrid cross?

The forked-line method.

What is the probability ratio for color in the F2 generation of a trihybrid cross?

3 yellow:1 green.

What is the probability ratio for shape in the F2 generation of a trihybrid cross?

3 round:1 wrinkled.

What is the probability ratio for height in the F2 generation of a trihybrid cross?

3 tall:1 dwarf.

How is the probability of F2 offspring having specific traits calculated in a trihybrid cross?

By multiplying the probability for each individual trait.

What occurs during the process of crossover in meiosis?

Homologous chromosomes align and exchange segments of genetic material.

What is the result of crossover in terms of chromosome types?

Two recombinant and two non-recombinant chromosomes.

What does the recessive c allele in mice do?

It does not produce pigment, resulting in an albino mouse if homozygous recessive.

What is the relationship between the A gene and the C gene in mice regarding coat color?

The C gene is epistatic to the A gene, affecting pigment production.