6 - Inheritance, Variation and Evolution

• Vector: A carrier used to transfer a gene from one organism to another
• Adult 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
• 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
• Family tree: A chart used to show the inheritance of a condition in a family
• Genotype: An organism’s genetic composition
• Heterozygous: When someone has two different alleles of a gene e.g
• Meiosis: A form of cell division that produces gametes, non-identical cells with half the usual number of chromosomes
• GM crops: Crops that have had their genomes modified by the insertion of a desired gene from another organism
• Extinction: The death of all members of a species
• 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
• Gametes: Sex cells (sperm and egg 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
• Fossil: The remains of dead organisms found in rocks which are millions of years old
• Linnaean system: The classification of organisms into kingdom, phylum, class, order, family, genus and species, as developed by Carl Linnaeus
• Fertilisation: The fusion of the nucleus of male and female gametes
• MRSA: A type of bacteria that is resistant to the antibiotic, methicillin
• Restores the full chromosome number
• Mutation: A random change in DNA which may result in genetic variants
• Evolutionary tree: A diagram which illustrates the evolutionary relationships between organisms