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NCEA Level 1 genetic
NCEA Level 1 genetics external
| Term | Definition |
|---|---|
| Haploid | Half a set of chromosomes from only one parent (23 for humans) |
| Diploid | A full set of chromosomes, half from the mother and half from the father (46 total, 23 from each parent) |
| DNA Replication | The copying of genetic information that occurs before a cell divides to ensure that there are enough chromosomes in each daughter cell |
| semi-conservative | A strand of each double helix is a parent and the other is a daughter |
| Meiosis | Cell division that produces sex cells (gametes) |
| Mitosis | A type of cell division that creates daughter cells genetically identical to each other and the parent |
| Trait | A characteristic that determines someone's appearance or personality |
| Gene | A segment of DNA that codes for a particular trait |
| Allele | A particular version of a gene |
| complementary base pairing | The rule that determines which bases can connect; A-T, C-G |
| Homologous pairs | Pairs of chromosomes, one from each parent, that contain the same genes in the same loci. The alleles can be different |
| Natural Selection | The increased survival of a organism with a particular trait due to changes in the environment and selection pressures |
| Heterozygous | A genotype with two different alleles e.g Nn |
| Homozygous | A genotype with two of the same alleles e.g NN |
| Recessive | An allele that can only be expressed in the phenotype if there is no dominant allele to mask it |
| Dominant | An allele that is expressed in the phenotype and masks any recessive allele. |
| Genotype | The two alleles (one from each parent) that determine the phenotype of an organism |
| Phenotype | The way alleles are expressed/The trait expressed |
| Selection Pressures | Pressures such as lack of food that cause natural selection |
| Variation | The difference in traits within a population |
| Mutation | A permanent change in the sequence of DNA due to addition, deletion or substitution. They can be harmful, beneficial or neutral. |
| Nucleuotide | the sequence that makes up DNA; a sugar, phosphate and a base |