Genetics Quiz # 1

• Heredity: The passing of traits from parent to offspring
• Genetics: The study of heredity and variation
• Gene: Segment of DNA molecule that codes for a particular trait
• DNA (deoxyribonucleic acid): Carries genetic information in a cell
• Locus: Location of a gene on a chromosome
• Sexual reproduction: Individuals are produced by the fusion of two sex cells (genetically different from either parent)
• Polyploid: Contain three or more sets of chromosomes. Many plants are polyploids
• Asexual reproduction: New individual is produced from a single parent cell by cell division (genetically identical to parent)
• Fragmentation: When an organism breaks down into several fragments, each fragment develops into an individual and is a clone of the original organism
• Mitosis: The stage where the nucleus is divided. Two copies of the DNA separate to opposite ends of the cell. Each new nucleus has the same number of chromosomes and DNA as the original parent cell
• Interphase: The longest phase where cells grow, perform normal functions, and prepare to divide by replicating DNA and organelles
• Chromatin: The chromosomes form a tangled mass of DNA and protein
• Sister chromatid: Identical copies formed by DNA replication of a chromosome, joined by a common centromere
• Cytokinesis: The final stage of cell division where 2 separate cells are formed with a complete copy of the parent's DNA and organelles
• Cloning: The process of producing offspring that are genetically identical to another, using a single cell or tissue
• Biotechnology: Technology that utilizes biological systems, living organisms, or parts of this to develop or create different products
• Genetically modified: Organism whose genetic material has been altered using genetic engineering techniques
• Organism: All living things
• Gamete: Sex cells. Male sex cell (sperm) and female sex cell (egg)
• Fertilization: Sperm implanting in an egg
• Zygote: Fertilized egg cell from the union of egg & sperm
• Meiosis: Cell division that produces reproductive cells in sexually reproducing organisms
• Homologous chromosome: Carry information for the same hereditary traits as its partner
• Tetrad: A pair of homologous chromosomes, each with two sister chromatids
• Synapsis: The physical pairing up of homologous chromosomes during prophase Ⅰ of meiosis
• Crossing over: The exchange of chromosome segments between homologous pairs during synapsis
• Gametogenesis: The formation of sex cells in meiosis
• Spermatogenesis: The formation of sperm cells in the testes
• Oogenesis: Formation of egg cells (ova) in the ovaries
• Karyotype: Chromosomes of an individual sorted and arranged according to size and type
• Sex chromosome: Located at the 23rd pair of homologous chromosomes
• Autosomes: All other chromosomes that are not sex chromosomes
• Nondisjunction: Failure of homologous chromosomes or sister chromatids to separate properly during cell division
• Trisomy: 3 homologous chromosomes in place of a pair
• Monosomy: Only one chromosome from a pair is present in cells rather than the two copies usually found in diploid cells
• Down syndrome: Born with an extra chromosome 21
• Prenatal testing: Ultrasound, Amniocentesis – uses a needle to inject into the womb and extract amniotic fluid to test fetal DNA
• Mistakes in Meiosis:

  • Monosomy: Single chromosome in place of a homologous pair
  • Polysomy: A condition in which an organism has at least one more chromosome than normal
• Down Syndrome: Condition in which a baby is born with an extra chromosome number 21
• Aneuploidy: The condition of having an abnormal number of chromosomes in a haploid set