Science Exam

Alleles - Alternative forms of a gene occupying the same position on a homologous chromosome Autosome - chromosomes other than sex chromosomes Basic DNA structure - Chromosomes - Protein bodies in the nucleus usually constant in number for a given species and bearing the genes. chromatid - arms of X shaped chromsome Diploid - Having 2 sets of chromosomes which is written like 2n Dominant - A gene that is the only one to appear in the off spring Gamete - A haploid reproductive cell Genes - a unit of heredity transferred from a parent to a child genotype - the genetic constitution of an organism haploid - having only a single set of chromosomes written as n heredity - the passing of features from one living thing to its off spring heterozygous - having 2 different alleles of a particular gene homologous - "Paired" Chromosomes ie the same genes in the same position homozygous - having identical alleles for the characteristic in question hybrid - heterozygous for the character in question ie the result of crossing two pure breeding parents with a different characteristic meiosis - the reduction divisions during which the chromosomes number is halved in forming the gametes mitosis - the process by which the nucleus is divided into 2 daughter nuclei each with an identical chromosome mutation - any change in the hereditary material phenotype - the outward expression of the genotype recessive - an allele if it is expressed only in the homozygous condition test cross - a cross between an individual displaying a recessive trait and a dominant trait sex chromosomes - X and Y chromosomes in humans control the gender zygote - the diploid cell produced at fertilization Atomic number - number of protons mass number - protons + neutrons isotopic notation - properties of metals - Malleable, Ductile and Good Conductors of Heat and Electricity properties of ionic compounds - high melting and boiling points, brittle, does not conduct electricity in solid state but does conduct electricity in liquid form, the solubility varies reactivity - the tendency of a substance to undergo a chemical reaction electronegativity - Atoms ability to attract electrons what is metallic bonding - the electrostatic attraction between cations and delocalised electrons monatomic ions - ions formed from a single atom polyatomic ions - ions that are made of more than one atom Ionic bonding model - 3D lattice is held together by a strong electrostatic attraction Why cant ions conduct electricity in a solid state? - because in a crystal structure the ions are in a fixed position but when melted or dissolved the ions are freely moving properties of acids - tastes sour, corrosive and pH under 7 properties of bases - tastes bitter, slippery corrosive, pH over 7 Chemical potential energy - the energy stored in the chemical bonds of a substance exothermic reactions - reactions that release energy, reactant has more energy than product endothermic reactions - reactions that absorb energy, product has more energy than reactant 3 circuit components - Path, source, a load conventional current vs electron flow - Conventional current flows from the positive terminal to the negative and electron goes the other way. Voltage - an electromotive force or potential difference expressed in volts. resistance - measure of the opposition to current flow in an electrical circuit. Ohm's Law - V=IR Ohm's Law - v= voltage, I= current, R= resistance