Genetics

Scientific study of heredity

Fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell.

True-Breeding

Term used to describe organisms that produce offspring identical to them if allowed to self-pollinate.

Trait

Specific characteristic that varies from one individual to another.

Hybrid

Offspring of crosses between parents with different traits

Gene

Sequence of DNA that codes for a protein and thus determines a trait.

Allele

One of a number of Different forms of a gene.

Segregation

Separation of allele during gamete formation

Gamete

Specialized cell involved in sexual reproduction.

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Key Concept Questions

1

How do geneticists use the principle of Probability?

A:

The principle of dominance states that some alleles are dominant and others are recessive.

2

How do geneticists use Punnett squares?

A:

When each F1 plant flowers and produces gametes, the two alleles segregate from each other so that each gamete carries only a single copy of each gene. Therefore, each F1 plant produces two types of gametes-those with allele for tallness and those with the allele for shortness.

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Vocabulary  words

Meanings / Explanation

1

Probability

Likelihood that a particular event will occur.

2

Punnett Square

Diagram showing the gene combinations that might result from a genetic cross.

3

Homozygous

Term used to refer to organism that has two identical alleles for particular trait.

4

Heterozygous

Term used to refer to an organism that has two different alleles for the same trait.

5

Phenotype

Physical characteristics of an organism.

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Genotype

Genetic makeup of an organism

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Key Concepts Questions

1

How do geneticists use the principle of probability?

The Principle of probability can be used to predict the outcomes of genetic crosses.

2

How do geneticists use Punnett Squares?

Punnett squares can be used to predict and compare the genetic variations that will result from a cross.

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Vocabulary words

Explanation / Meanings

1

Independent assortment

Independent segregation of genes during the formation of gametes.

2

Incomplete dominance

Situation in which one allele is not completely dominant over another.

3

Codominance

Situation in which both alleles of gene contribute to the phenotype of the organism.

4

Multiple alleles

Three or more alleles of the same gene.

5

Polygenic traits

Trait controlled by two or more genes.

Key Concept Questions

1

What is the principle of Independent assortment?

The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes. Independent assortment helps account for many genetic variations observed in plants, animals, and other organisms.

2

What inheritance patterns exist aside from simple dominance?

Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

Vocabulary words

Explanation / meanings

Homologous

Term used to refer to chromosomes that each has a corresponding chromosome from the opposite-sex parent.

Diploid

Term used to refer to a cell that contains both sets of homologous chromosomes

Haploid

Terms used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes.

Meiosis

A process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

Tetrad

Structure containing 4 chromatids that forms during meiosis

Crossing-over

Process in which homologous chromosomes exchan