Genetics

  • Genetics is the study of how traits are passed from one generation to the next.

     

    Reproduction is a process that produces a new generation of offspring.

     

    Gregor Mendel is the “father of genetics”, because he discovered most of principles of heredity while studying pea plants.

     

    A trait is an observable characteristic that is passed from one generation to the next.

     

    Heredity  is passing traits from parent generations to offspring generations.

     

    A chromosome is a thread-like structure in the nucleus of a cell that controls heredity.

     

    A gene (Allele) is part of a chromosome that carries the genetic information to control one trait.

     

    Deoxyribonucleic Acid or DNA is the chemical in chromosomes that contains the genetic code for heredity.  It is shaped like a double helix (a twisted ladder shape).

     

    The nucleus is a cell organelle that stores chromosomes.

     

    A dominant gene is the stronger form of a gene.  It will show up in an offspring that gets that gene.  It is represented by a capital letter.

     

    A recessive gene is the weaker form of a gene.  It will get masked in a hybrid offspring with that gene.  It is represented by a lower case letter.

     

    A purebred is an offspring that has two genes for a trait that match.  They are both dominant or both recessive.

     

    A hybrid is an offspring that has two genes for a trait that don’t match. One will be the dominant gene & the other will be recessive.

     

    A gamete is a sex cell (sperm or egg cell).

     

    Fertilization occurs when a sperm cell unites with an egg cell.

     

    Sexual reproduction requires two sets of DNA, one set from each of two parents, combining to produce an offspring.

     

    Asexual reproduction only requires one set DNA from one parent to produce an offspring.

     

    Cell division is the process by which cells reproduce.

     

    Mitosis is cell division where one cell splits into two cells.

     

    Meiosis is cell division where one cell splits into four gametes.

     

    Variation is the genetic differences between individuals of the same species that are caused during sexual reproduction, by mutation or as a result of natural selection.

     

    X/Y chromosomes control the trait related to the gender of an offspring.

     

    A mutation is variation caused by miscoded DNA.

     

    Extinction occurs when the last of species dies because it didn’t adapt to change in the environment.

     

    Competition is trying hard to fulfill needs from limited resources over rival organisms in an effort to ensure survival.

     

    Natural selection is the process where nature eliminates organisms that don’t adapt to a changing environment or can’t compete for limited resources.

     

    A pedigree chart is a graphic family history that shows how a trait has been passed from one generation to later ones.

     

    A Punnett square uses parent’s genes to help predict the chances of a trait being exhibited in an offspring.

     

    A Genotype is a description of the gene pair that an offspring inherits for a trait. One of the pair comes from the mother & one from the father.

     

    A Phenotype is a description of what a trait looks like for an offspring.