A length of DNA coding for a protein/feature/characteristic or trait.
A version of a gene. Eg. T - tongue roller; t - non tounge roller
Double stranded long molecule made up of nucleotides;found in the nucleus of cells;codes for an individual's make up
what is the base pairing rule?
DNA is made up of nucleotides. the babses always pair in the same combination.
Adenine - Thymine (A-T)
Guanine - Cytosine (G-C
A change to the DNA; can be caused by mutagens; is only passed on if it occurs in the gametes;a mutation is the 'ultimate' source of variation as it is the only source of new alleles
What is DNA replication?
A process which occurs prior to cell division to ensure that the full amount of DNA is present to produce new cells. After DNA replication, a single chromosome consists of two identical chromatids
what is a gamete?
A sex cell e.g Egg or sperm in animals. Needed for sexual reproduction; contains the haploid number of chromosomes so that when it fuses with another gamete, the diploid number is restored.
What is pure breeding?
Homozygous dominant or homozygous recessive - both alleles are the same for the gene. If two pure breeding organisms mate, they will only produce offspring of the same phenotype as the parents.
A characteristic or feature determined by an organisms genotype
Nucleotides are the building blocks of DNA. Each nucleotide is made up of a sugar, a phosphate, and a base. There are four bases; A-T and G-C
What is test cross used for?
used to determine whether an individual who shows the dominant phenotype is homozygous or heterozygous by crossing the individual with a homozygous recessive individual and then looking at the offspring.
differences between organisms within a population or species due to differences in the genetic code (order of the bases on DNA)
Define sexual Reproduction
reproductions requiring two parents - resulting offspring will carry a combination of the parents genes. Sexual reproduction will produce variety in a population or species
reproduction requiring just one parent. Offspring will be genetically identical to the parent and to each other - clones.