Biology Chapter 4: Pea Plants and Genetics

Study Notes

Genetics Key Terms

Gene: A DNA sequence that encodes a protein, influencing specific traits in an organism.
Allele: Variants of a gene; can be dominant (show up in phenotype) or recessive (masked by dominant alleles).
Dominant Allele: Exhibits its trait in the presence of another allele, ensuring the trait is expressed.
Recessive Allele: A trait that remains hidden when a dominant allele is present; only expressed when homozygous.
Heterozygous: Possessing two different alleles for a single trait, leading to variation in expression.
Homozygous: Having two identical alleles (either dominant or recessive) for a given gene.
Homozygous Recessive: When an organism has two recessive alleles for a trait, resulting in the expression of the recessive phenotype.
Homozygous Dominant: An organism with two dominant alleles for a trait, guaranteeing the dominant phenotype.

Genetic Tools and Concepts

Punnett Square: A graphical method used to predict all possible allele combinations from a genetic cross, assisting in determining potential genotypes and phenotypes of offspring.
Probability: A numerical expression of the likelihood that a specific genetic outcome will occur in a given cross.

Fundamental Genetic Principles

Trait: A heritable characteristic passed from parent to offspring, fundamentally determined by genes.
Gregor Mendel: Known as the father of genetics, Mendel's studies on pea plants laid the foundation for understanding inheritance patterns.
Law of Segregation: Mendel's principle that alleles for each trait segregate independently during gamete formation, thus separate into different gametes.
Chromosome Theory of Inheritance: Proposes that genes are located on chromosomes, which are the structures responsible for inherited traits.

Genetic Composition

Genotype: The complete genetic constitution of an organism, consisting of the specific alleles present.
Phenotype: The observable characteristics of an organism resulting from the expression of its genotype, influenced by environmental factors as well.

Description

This quiz focuses on key concepts from Chapter 4, specifically exploring pea plants, Mendelian genetics, and Punnett squares. Review important terms like gene, allele, dominant allele, and recessive allele to strengthen your understanding of inheritance.