Biology Chapter 12: Gregor Mendel Flashcards

Mendel's Experiments and Key Concepts

• Gregor Mendel utilized pea plants as his model system for studying heredity.
• Genetics is defined as the study of heredity and variation in inherited characteristics.
• True breeding plants are homozygous, having identical alleles for a trait.

Observed Traits and Terms

• Mendel's key traits included flower color (purple/white), plant height (tall/short), and pod shapes (smooth/constricted).
• When true breeding parents were crossed, the first generation (F1) offspring were heterozygous.

Flower Anatomy and Pollination

• The male parts of a flower are called the anther and filament.
• Female flower parts include stigma, style, pollen tube, ovary, and ovule.
• Pollination involves the transfer of pollen from the anther to the stigma.
• Cross pollination occurs when pollen from one flower is transferred to another flower.

Principles of Inheritance

• Mendel's First Principle states that inheritance involves genes passed from parents to offspring.
• Alleles are different forms of a gene, with dominant alleles expressed fully, and recessive alleles only expressed when paired with another recessive allele.
• Mendel's Second Principle highlights that some alleles are dominant while others are recessive.
• His Third Principle explains that each adult has two gene copies, one from each parent, which segregate during gamete formation.
• A gamete is defined as a sex cell.

Genetic Terminology

• Homozygous refers to having two identical alleles for a trait.
• Heterozygous indicates having two different alleles for a trait.
• Genotype is the genetic makeup of an organism, while phenotype describes its physical appearance or visible traits.
• Probability refers to the likelihood of a particular event occurring.

Predictive Tools in Genetics

• A Punnett Square is a diagram used to predict the outcome of a breeding experiment.
• In a typical cross, probabilities for offspring traits such as brown eyes (75%) and blue eyes (25%) can be calculated.

Additional Principles and Advanced Concepts

• Mendel's Fourth Principle establishes that alleles for different genes usually segregate independently.
• Non-Mendelian traits do not follow traditional inheritance patterns, indicating complex genetics.
• Incomplete dominance occurs when one allele is not completely dominant over another.
• Codominance involves the clear expression of both alleles' phenotypes.
• Multiple alleles refer to genes existing in more than two forms.
• Polygenic traits result from the interaction of several genes impacting a single trait.
• Environmental conditions can influence gene expression alongside genetic factors.

Explore the foundational principles of genetics through this quiz focused on Gregor Mendel's experiments. Test your knowledge on key concepts such as heredity, true breeding plants, and the significance of Mendel's model system. Perfect for biology students and anyone interested in the science of inheritance.