| A | B |
|---|
| Gamete | Sex cell |
| Sperm | Male sex cell |
| Ova | Female sex cell |
| Gonads | Sex organ |
| Fertilisation | Process of sperm unitng with ova to form a zygote |
| Chromosome | Strand of DNA that carries genetic genes of an individual |
| Autosomes | Non-sex chromosomes |
| Gene | Area on a chromosome that determines a feature |
| Allele | Alternative form of a gene |
| Genotype | Genetic makeup of an individual |
| Phenotype | Physical appearance of an individual |
| Homologous chromosome | Similar pairs of chromosomes containg genes which control simlar characteristics |
| Homozygous | 2 genes are the same for a particular feature |
| Heterozygous | 2 genes different for a particular feature |
| Locus | Position on the chromosome that is occupied by a certain allele |
| Trait | Feature of an organism |
| Number of autosomes and sex chromosomes | 2 sex, 44 autosomes |
| Huntington's Chorea | Dominant, autosomal. Symptoms include involuntary flaling of arms and eventual dementia. Apperas after age of 40 and life expectancy is about 60 |
| Phenylketonuria | Recessive, autosomal. Symptoms include mental retardation and epileptic seizures. Due to the gene concerned controlling the production of phenylalanine hydroxylase. This enzyme converts phenylalanine to tyrosine. If enzyme not present than a build up occurs and becomes toxic. Identified at birth by screening. Special diets restriciting intake can correct symptons |
| Duchenne Muscular Dystrophy | Recessive, sex linked. Is wasting away of leg muscles. Becomes apparent 3-5 yrs with weakness in muscle meaning cannot climb well, stumbling, having trouble standing up. Muscle replaced by fatty substance and bedridden/wheelchair at 12yrs. Respiratory failure, little chance of living beyond 25 |
| Polygeny | Situation where a phenotype is determined by more than one gene |
| Population | Group of interbreeding organisms of the same species living together |
| Gene pool | Total variety of genes present in a reproducing population |
| Species | Group of similar individuals whcih can interbreed to produce fertile offspring |
| Evolution | Change in the gene pool over time |
| Variation | Differences between members of the same species. Due to mutation, migration, |
| Mutation | Spontaneous, permanent change in the structure of a cell |
| Random genetic drift | Small poulations have random, non directional variation in the allele frequence |
| Haemophilia | Blood doesn't clot |
| DNA | Dioxyribose Nucleic Acid |
| Heriditary | Passing of charactersitics from parent to offspring |
| Centromere | Point of attachment of chromatids |
| Monogenic | Characteristics determined by a single pair of genes |
| Competition | More offspring than resources means a fight for these things to survive |
| Selection | Individuals with variations better suited to their environments have a better chance of surviving |
| Causes of mutation | Radiation, High temperatures, chemicals or spontaneous |
| Adaptation | Characteristic of an organism that increases the chance of surviving and reproducing in an environment |
| Speciation | Fomration of two species, each with their own gene pool, from an original,single population. Variation, Isolation and Natural selection contribute to this |
| Isolation | Pops become seperated by a geographical or social barrier into two sperate populations where no interbreeding occurs |
| Homologous organ | Organs from different species with a similar structure |
| Vestigal organs | Undersized/no function of organs within an organism |
| Fossils | Preserved trace of a once living organism. Can trace these back to a common ancestor/evolutionary changes |
| Comparitive Protein analysis | Similarities between sequences of amino acids - Guanine, Cytosine and Tyrosine |
| Comparitive Antomy analysis | Compare structural similarities of a species to work out evolutionary relationships and prove common ancestor |
| Comparitive embryology | Compare development to see structural similarities at embryo level to suggest a common ancestor |
| Evolution due to... | Natural selection, Mutation, Isolation, Random genetic drift and migration |
| Principle of segregation | Each gamete receives only one factor or gene for each trait (when joined get one from each) |
| Monohybrid cross | Only one pair of contrasting characteristics being considered |
| Dihybrid cross | 2 pairs of contrasting characteristics being considered |
| Melanocytes | Synthesise melanin (pigment) for tyrosine - skin colour |
| Types of single gene disorders | Inheritance of a single defective gene or mutation. Types are dominant, recessive or sex linked |
| Multiple alleles VS polygenic inheritance | Multiple alleles - inheritance of a characteristic which has more than two alleles. Polygenic - Characteristic dependant on many gene pairs |
| gene linkage | genes in a partic chromosome are linked together to from a set |
| Epistasis | Situation where a gee at one locus has a controlling effect of genes at other loci eg Albino |
| Red/green colour blindness | Sex linked recessive, inability to discriminate between green and red, no cure |
| Environmental factors which cause variation | Temperature, pollution levels, UV Radiation, working conditions, foods eaten |
| Definition fo DNA | Compound consisting of rebose, phosphate and nucleic acid bases. In a double helix shape. |
| Pure breeding | Produce the same characteristic in each succeeding generation when bred amon themselves |
| Sickle cell anaemia | Death in homozygous (recessive), heterozygous have some sickling of cells which can be dangerous in low O2. Advantageous in areas of malaria because of shape. |
| Genetics | Study of the mechanisms by which characteristics are passed on from parent to offspring |
| Hemizygous | No alleic counterpart |
| Law of independant assortment | Held true only if gene located in seperate pairs of chromosomes (cause law states thatcharactersitics controlled by genes on diff chromosomes) |
| Genetic counselling | Contemplating having a child needing advice about risks of a child defect |
| Darwin's theory of natural selction based on | Variation (all vary), birth rate (numbers outweigh resources), nature's balance (numbers at constant level) |
| Geograohical barriers | Oceans, mountains, lakes, desert and ice |
| Sociocultural barriers | Economic status, educational background, religion, language and social posisiton. |
| Founder effect | Small group move away but not genetically representive of orig population |
| cytology | Study of cells |
| progeny | Offspring |
| punnet quare | Work out genetic problems |
| co dominance | Neither allele masks the other |
| consanguineous marriage | Marriage between teo close relatives eg cousins |
