heredity

• Mendel's laws of inheritance state that traits are inherited in predictable patterns, such as dominant and recessive alleles.
• Heredity is the transfer of characters from parents to offspring
• Inheritance is the process through which characters pass from one generation to another
• Traits are characteristic features of an organism, present in a physical form that is visible or in a physiological aspect
• Genes are the units of heredity which transfer characteristics from parents to their offspring during reproduction
• Due to differences in genetic makeup, human population show a great deal of variations
• Attached and free earlobes are two variations found in the human population
• Genes are the functional units of DNA that define our characteristics
• Allele: One of the different forms of a particular gene, occupying the same position on a chromosome
• Mendel chose to work with pea plants to study genetics because they have easily identifiable traits
• Pea plants are either tall or short, which is an easy trait to observe
• Pea plants grow quickly, allowing for many experiments in a short period of time
• Pea plants can either self-pollinate or be cross-pollinated
• Self-pollination involves one flower, where the flower's own pollen lands on the female sex organs
• Chromosomes are thread-like structures in the nucleus of the cell that carry genes
• Gene is a functional unit of heredity present on chromosomes of the cell nucleus
• Allele is a different form of a given gene, e.g., T-allele for tallness and t-allele for dwarfness
• Phenotype refers to the observable physical appearance of an organism, like tall plant or dwarf plant
• Genotype refers to the genetic code responsible for any given phenotype, like (TT) for tallness and (tt) for dwarfness
• Homozygous refers to the condition when the same type of allele is present for a given phenotype, e.g., (TT) is homozygous tall
• Heterozygous refers to different types of alleles, e.g., (Tt) is heterozygous
• F1 Generation is produced as a result of cross-fertilization
• F2 Generation is produced as a result of selfing or self-fertilization of F1 generation
• Haploid cells contain only one set of chromosomes (n)
• Diploid cells contain two sets of chromosomes (2n)
• All cells of the human body are diploid except sperm and ovum
• Mendel used contrasting visible characters of garden peas for his experiments
• He crossed tall and short plants and calculated the percentages of tall or short progeny
• Monohybrid Cross has a phenotypic ratio of 3:1 and a genotype ratio of 1:2:1
• Dihybrid Cross considers two characters simultaneously
• Phenotypic Ratio (F1 Generation) is 9:3:3:1
• Law of Dominance states that some alleles are dominant and cover up recessive alleles
• Each character is controlled by a pair of genes, and if the pairs are heterozygous, one will always dominate the other
• Law of Segregation is the second law of inheritance where an organism has two alleles for each gene but can only pass on one
• Law of Independent Assortment states that the assortment of each pair of traits is independent of the other
• During gamete formation, one pair of trait segregates from another pair of traits independently
• Cellular DNA is the information source for making proteins in the cell
• Genes provide information for specific proteins, determining traits like plant height
• Sex Determination is the process by which the sex of an individual is decided based on its genetic material composition
• Sex determination in Humans involves 22 pairs of autosomes and 1 pair of sex chromosomes (XY for male and XX for female)