Unit 1 - Genetics

• Genetics


  The branch of biology dealing with heredity and the variation of inherited characteristics
• Sexual reproduction

  Individuals are produced by the fusion of two sex cells (genetically different from either parent)
• DNA (deoxyribonucleic acid)


  A molecule that carries genetic information in cells
• Heredity


  The passing of traits from parent to offspring
• Gene


  A segment of a DNA molecule that codes for a particular trait; found at a specific location on a chromosome
• Locus


  The location of a gene on a chromosome
• Polyploid

  Contain three or more sets of chromosomes. Many plants are polyploids
• Interphase


  The longest phase. Cells grow and perform their normal function. Cell prepares to divide by replicating its DNA and organelles so they can be shared between the new cells
• Chromatin


  The tangled strands of DNA and protein within a eukaryotic nucleus
• Fragmentation

  A method of asexual reproduction in which a piece or body fragment of the parent organism develops into a mature individual
• Mitosis


  The process by which a eukaryotic cell divides the genetic material in its nucleus into two identical nuclei
• Organism


  A living thing that has an organized structure, can react to stimuli, reproduce, grow, adapt, and maintain homeostasis
• Biotechnology


  The use and modification of organisms for applications in engineering, industry, and medicine
• Sister chromatid


  The identical copy of a single chromosome that remains attached to the original chromosome at the centromere
• Cytokinesis

  The final stage of cell division. 2 separate cells are formed - cytoplasm divides to form two identical cells
• Asexual reproduction


  New individual is produced from a single parent cell by cell division (genetically identical to parent)
• Gamete

  Sex cells (sperm and egg) are also known as gametes (sex cells). These have half the chromosomes
• Genetically modified


  An organism in which the genetic material has been altered using genetic engineering techniques
• Cloning


  The process of producing offspring that are genetically identical to another, using a single cell or tissue
• Zygote


  A cell formed by the fusion of two sex cells. The zygote is diploid (2n)
• Fertilization


  Sperm implanting in an egg. Results in the formation of a zygote (fertilized egg cell from the union of egg & sperm)
• Synapsis


  The physical pairing up of homologous chromosomes during prophase Ⅰ of meiosis
• Meiosis

  A form of cell division in which a single cell gives rise to four haploid daughter cells
• Ova


  Female sex cells (egg cells)
• Homologous chromosome

  Chromosomes that are not identical, they are similar in size, shape, and gene arrangement. Together these matching chromosomes are called a homologous pair
• Crossing over


  The exchange of chromosome segments between homologous pairs during synapsis
• Oogenesis


  The production of mature egg cells
• Spermatogenesis


  The production of mature sperm cells
• Sex chromosome


  Chromosomes that differ in males and females of the same species; the combination of sex chromosomes determines the sex of the offspring
• Trisomy


  A chromosomal abnormality in which there are three homologous chromosomes in place of a homologous pair
• Gametogenesis

  The production of gametes (sex cells) in animals
• Karyotype


  The chromosomes of an individual that have been arranged and sorted according to size and type
• Nondisjunction

  The failure of homologous chromosomes to move to opposite poles of the cell during meiosis; results in an abnormal number of chromosomes in the daughter cells
• Autosomes

  Non-sex chromosomes
• Down syndrome


  A chromosomal abnormality in which an individual has three copies
• Monosomy


  A chromosomal abnormality in which there is a single chromosome in place of a homologous pair
• iosis results in an abnormal number of chromosomes in the daughter cells
• Trisomy


  A chromosomal abnormality with three homologous chromosomes in place of a homologous pair
• Monosomy


  A chromosomal abnormality with a single chromosome in place of a homologous pair
• Nucleotide

  The repeating unit in DNA comprising a deoxyribose sugar, a phosphate group, and one of the four nitrogenous bases