Inheritance Variation and Evolution

• Somatic cell cloning


  A type of cloning that forms an embryo from an adult body cell
• Allele


  A version of a gene
• Amino acids


  Small molecules from which proteins are assembled
• Archaea


  Primitive bacteria existing in extreme environments
• Asexual reproduction


  A form of reproduction involving a single parent. Creates genetically identical offspring
• Binomial system


  The universal system of naming organisms using their genus and species
• Charles Darwin


  The scientist who developed the theory of evolution by natural selection
• Chromosome


  A long, coiled molecule of DNA that carries genetic information in the form of genes
• Classification


  The organisation of organisms into groups based on their characteristics and structure
• Coding DNA


  A sequence of DNA that codes for the production of a protein
• Complementary


  Describes how the chemical bases in DNA pair up with each other. A pairs with T and C pairs with G
• Cuttings


  The simplest method of cloning plants. A branch is cut from a parent plant and replanted in compost after removing the lower leaves
• Cystic fibrosis


  A cellular membrane disorder resulting from the presence of a recessive allele
• DNA


  A double-stranded polymer wound to form a double helix. Carries the genetic code
• Dominant


  Describes an allele that is always expressed. Represented by a capital letter
• Embryo screening


  A procedure used to determine the presence of faulty genes in an embryo produced by IVF. A few embryonic cells are removed and screened for defective alleles
• Embryo transplants


  The simplest method of animal cloning. Cells are removed from a developing embryo, split apart and grown in culture, before being transplanted into host mothers
• Evolution


  The gradual change in the inherited traits within a population over time. Occurs due to natural selection
• Evolutionary tree


  A diagram which illustrates the evolutionary relationships between organisms
• Extinction


  The death of all members of a species
• Family tree


  A chart used to show the inheritance of a condition in a family
• Fertilisation


  The fusion of the nucleus of male and female gametes. Restores the full chromosome number
• Fossil


  The remains of dead organisms found in rocks which are millions of years old
• Gametes


  Sex cells (sperm and egg cells) with half the usual number of chromosomes (haploid)
• Gene


  A section of DNA that codes for a specific sequence of amino acids which undergo polymerisation to form a protein
• Genetic engineering


  The modification of the genome of an organism by the insertion of a desired gene from another organism, enabling the formation of organisms with beneficial characteristics
• Genome


  The complete genetic material of an organism
• Genotype


  An organism's genetic composition. Describes all alleles
• GM crops


  Crops that have had their genomes modified by the insertion of a desired gene from another organism
• Heterozygous


  When someone has two different alleles of a gene e.g. Ff
• Homozygous


  When someone has two identical alleles of a gene e.g. ff
• Inbreeding


  The formation of offspring from the breeding of closely related individuals
• Linnaean system


  The classification of organisms into kingdom, phylum, class, order, family, genus and species, as developed by Carl Linnaeus
• Meiosis


  A form of cell division that produces gametes, non-identical cells with half the usual number of chromosomes
• Mitosis


  A form of cell division that produces two genetically identical daughter cells (with a full set of chromosomes) from one parent cell
• MRSA


  A type of bacteria that is resistant to the antibiotic, methicillin
• Mutation


  A random change in DNA which may result in genetic variants
• Natural selection


  The process by which the frequency of advantageous traits passed on in genes gradually increases in a population over time
• Non-coding DNA


  DNA which does not code for a protein but instead controls gene expression
• Nucleotide


  The monomers of DNA consisting of a common sugar, a phosphate group and one of four chemical bases (A, T, C, G) attached to the sugar