| what is inheritance | the transmission of genetic information from generation to generation |
| what is a chromosome | a thread-like structure of DNA, carrying genetic information in the form of genes |
| what is a gene | a length of DNA that codes for a protein |
| what is an allele | a version of a gene |
| what is a haploid nuclues | a nucleus containing a single set of unpaired chromosomes, e.g. in gametes |
| what is a diploid nucleus | a nucleus containing two sets of chromosomes, e.g. in body cells |
| in a diploid cell.... | chromosomes are arranged in pairs and in a human diploid cell there are 23 pairs |
| what is mitsosis | nuclear division giving rise to genetically identical cells, the exact duplication of chromosomes occurs before mitosis |
| roles of mitosis | the role of mitosis is growth, repair of damaged tissues, replacement of cells and asexual reproduction |
| what is meoisis | reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells, meiosis is involved in the production of gametes |
| what is a genotype | the genetic make-up of an organism in terms of the alleles present |
| what is a phenotype | the observable features of an organism |
| what is homozygous | having two identical alleles of a particular gene |
| what is heterozygous | having two different alleles of a particular gene |
| what is dominant | an allele that is expressed if it is present |
| what is recessive | an allele that is only expressed when there is no dominant allele of the gene present |
| example of a genetic diagram | here |
| what is variation | differences between individuals of the same species |
| what is phenotypic variation | variation caused by environment or lifestyle factors but also can be genetics eg. flamingos are pink due to their diet (naturally white). |
| what is genotypic variation | variation caused by inheritance eg. Some humans are tall because their parents are tall. |
| what is continouis variation | range of phenotypes between two extremes, e.g. height in humans |
| what is discontinuous varation | a limited number of phenotypes with no intermediates, e.g. tongue rolling. This is usually caused by genes alone |
| when does natrual selection occur | when there is variation in population |
| what is adaptation | the process, resulting from natural selection, by which populations become more suited to their environment over many generations |
| an example of genetic variation | the development of strains of antibiotic resistant bacteria. |
| what is selective breeding | humans specifically choose individuals with advantageous traits and cross them to create offspring that is significantly more advantageous, in the eyes of the humans. |
