Meiosis vs Mitosis Quiz

Introduction to Genetics

• Mendel's experiments with pea plants laid the foundation for the study of heredity.
• He used true-breeding plants (plants that would produce offspring identical to themselves).
• Mendel cross-pollinated plants with different characteristics to produce seeds with two different parents.
• This process is called cross-pollination.
• He studied different pea plant traits like seed shape and color, pod shape and color, flower position of the plant, and plant height.
• Each trait had two contrasting characters (e.g., round or wrinkled seeds, yellow or green seeds).
• The original pair of true-breeding plants is called the P (parental) generation and the offspring are called the F1 (first filial) generation.
• Each trait Mendel studied was controlled by one gene. Genes come in different versions called alleles.
• Mendel used this to form the four principles of inheritance.

Mendelian Genetics principles

• The first concept is that alternative versions of genes account for variations in inherited characters. These alternative versions are called alleles.
• For each character, an organism inherits two alleles, one from each parent. The two alleles at a locus on a chromosome may be identical (homozygous) or different (heterozygous).
• If the two alleles at a locus differ, then one (dominant allele) determines the organism's appearance, and the other (recessive allele) has no noticeable effect on appearance.
• The Law of Segregation states that the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes.

Non-Mendelian Inheritance

• Some alleles are neither dominant nor recessive, and some traits are controlled by multiple alleles or multiple genes.
• Incomplete dominance occurs when one allele is not completely dominant over another. In this case, the offspring heterozygous phenotype is between the two homozygous dominant parents.
• Codominance occurs when both alleles are expressed completely.
• Multiple alleles occur when a gene has more than two alleles.

Polygenic Inheritance

• Traits controlled by two or more genes are called polygenic traits.
• The genes for a polygenic trait may be scattered along the same chromosome or located on different chromosomes.
• Due to independent assortment and crossing-over during meiosis, many different combinations appear in offspring.

Meiosis

• Gametes are formed by the process of meiosis, which divides a diploid cell (having two sets of chromosomes) into four haploid cells (having one set of chromosomes).
• Meiosis involves two divisions: meiosis I and meiosis II.
• During meiosis I, homologous chromosomes pair and exchange genetic material (crossing over).

Mitosis

• Mitosis creates genetically identical cells, maintaining the same number of chromosomes and alleles as the original cell. It's used for growth and repair.

Other Concepts

• Fertilization: The process where sperm and egg cells join to create a new cell called a zygote.
• Punnett Square: A diagram used to predict the outcome of a genetic cross.
• Genotype: The set of alleles an individual has for a trait.
• Phenotype: The physical appearance of a trait.
• Heterozygous: Having two different alleles for a trait.
• Homozygous: Having two identical alleles for a trait.

Human Blood Types

• Blood type is an example of multiple allele inheritance, with three alleles (IA, IB, i) determining the four possible phenotypes (A, B, AB, and O).

Test your knowledge on the key differences between meiosis and mitosis, particularly focusing on chromosome number and genetic variation. Explore how the cells produced during meiosis differ between males and females, and learn about the role of polar bodies in female meiosis.