click below
click below
Normal Size Small Size show me how
Y11 Genetics
Vocabulary for Year 11 Genetics
Question | Answer |
---|---|
Genetic Variation | The genetic differences between organisms within a population |
Meiosis | A type of cell division used to produce sex cells (gametes) with half the number of chromosomes, produces 4 cells that are different to each other, and to the parent cell. |
Gamete | Sex cells- male (sperm) female (egg) that contain half the number of chromosomes. |
Zygote | A fertilised egg that contains the full number of chromosomes |
Sexual Reproduction | Reproduction involving two parents. The offspring inherit half the chromosomes from each parent and therefore a mix of alleles creating genetically unique offspring. |
Mutation | A random permanent change in the base sequence of the DNA, which is inheritable if it occurs in the sex calls. |
Crossing Over | During meiosis homologous pairs of chromosomes come together and swap sections of DNA giving each gamete a random combination of alleles. |
Independent Assortment | During meiosis homologous pairs of chromosomes line up randomly, meaning a random combination of alleles end up in each gamete |
Allele | Different versions of a gene can be dominant or recessive e.g. purple flowers (P) and white flowers (p) |
Dominant | The allele that will be "expressed" in the phenotype if it is present |
Recessive | The allele which is only expressed if there are two e.g. bb |
Trait | A genetically determined characteristic |
Genotype | The combination of alleles for each trait e.g. Pp, PP or pp |
Phenotype | The physical characteristics caused by the genotype |
Homozygous | Having two of the same allele, either PP (dominant) or pp (recessive) |
Heterozygous | Having a dominant and recessive allele e.g. Pp |
Pedigree Chart | A family tree showing inheritance patterns for specific traits. |
DNA | A strand of genetic information made up of phosphate and sugar backbone with bases paired A-T and C-G |
Chromosome | A strand of DNA containing many genes |
Homologous Pair of Chromosomes | A pair of identical chromosomes e.g. humans have 46 chromosomes made up of 23 homologous pairs |
Gene | A section of DNA that codes for a particular protein and therefore trait |
Bases | A (Adenine), G (Guanine), C (Cytosine), T (Thymine) pair together A-T and C-G. Triplets of bases e.g. TGA code for specific amino acids which combine to form proteins |
Amino Acid | Compounds which combine to make Proteins |
Protein | Compounds made up of amino acids combined |
Random Fertilisation | randomly selected male sex cell combines with randomly selected female sex cell to form a zygote |
Natural Selection | Organisms with characteristics best suited to their environment are better able to survive and produce offspring with the beneficial characteristic. |
Punnett square | Grid showing the combinations of genotypes that my occur when two organisms are crossed. |
Gene Marker | A gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species. |
DNA Sequencing | The process of determining the exact sequences of bases in an organisms DNA |