genetics Flashcards
Allele
the alternate versions of genes, created by a slight change in the base sequence
Cell
the smallest unit of life, either living alone or as part of a larger organism
chromosomes
coiled up DNA and proteins found in the nucleus of many cells.
cross pollination
pollen moving from one flower to another to increase variation.
DNA
the instruction carrying molecule, made of bases, sugar and phosphate.
dominant allele
the allele which only requires one copy to be present in the genotype, in order to be expressed in the organisms
fertilisation
the joining of a male and female sex cells
Gamete
the main name for any sex cells; male or female, plant or animal
Clones
individuals whose GENETIC CODE is identical to that of another individual ( engineered or natural- e.g identical twins
Gene
The code for one particular trait ( feature ) of an organism, such as hair colour, height, size of feet. It is made up of a pair of alleles
Genetic Code
a general name for the “blue prints” carried by organisms in their chromosomes. ( this can also be known as genetic material.)
Genetic Engineering
People using chemicals, radiation techniques and other methods to change the genetic code of organisms
Genetic variation
the difference between members of the same species. Only identical twins and clones don’t have genetic variation .
Genotype
the two letter code showing the 2 alleles present for the gene the code for the alleles being discussed; e.g Bb= one brown-eyed allele (B) plus one blue-eyed allele
Heterozygous
when the two alleles are different; E.g Bb
Homologous chromosomes
The matching pair of chromosomes in the cell: 1 is from the mother and 1 is from the father
Homozygous
Having 2 pf the same alleles for the gene: BB or bb for the eye colour gene
meiosis
Cell division for sexual reproduction: creates the gametes ( haploid n)
mitosis
cell division for growth and repair: creates body cells (diploid 2n)
Offspring
The general name for the offspring of an organism.
phenotype
the physical expression of a gene : eye colour, height, hair line .
Recessive allele
the allele which only requires two copies to be present in the genotype, in order to be expressed in the organism phenotype
