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A base found in DNA which bonds with Thymine. These make a base pair that form "rung" in the DNA structure.
A base found in DNA which bonds with Guanine. These make a base pair that form "rung" in the DNA structure.
A base found in DNA which bonds with Cytosine. These make a base pair that form "rung" in the DNA structure.
A base found in DNA which bonds with Adenine. These make a base pair that form "rung" in the DNA structure.
A length of DNA, which holds the genes; thread like structures that are visible before a cell divides. They are found in the nucleus of the cell. Humans have 23 homologous pairs.
The type of cell division which produces sex cells/gametes (sperm and eggs; pollen and ova). In animals it happens in the ovaries and testes. Each gamete contains half the genetic information of normal cells (i.e. 23 chromosomes in humans).
The combination of two alleles that an organism has for a particular gene. This is the code for the alleles.
Two copies of a chromosome that have the same shape and structure and carry the same genes.
Form of reproduction involving the fusion of two gametes from two parents. Produces variation in offspring.
The sex cells. A cell that contains half the genetic information that has to join with another gamete to form a zygote before further development can occur.
A fertilised egg. A single cell containing chromosomes from both the male gamete and the female gamete.
The exchange of genetic material between homologous chromosomes which occurs during meiosis and contributes to genetic variation.
Name for the process where chromosomes line up in random order at the cell equator during meiosis which results in a random combination of alleles in a particular gamete.
Photograph of individual chromosomes of a cell arranged in pairs and showing their size number and shape.
The ratio/relationship of one part to another e.g. 2 out of every 3 offspring are blue eyed.
The relationship of one number to another. E.g. 2 blue eyed offspring: 1 non-blue eyed offspring.
Occurs when the environment "selects" the best phenotypes. Often referred to as "survival of the fittest", as a result the species changes
A process that is used to breed for specific required traits e.g. cattle with more muscle, flowers with better smell.
Group of plants or animals differing only slightly from others and capable of interbreeding.
A population is all the organisms that both belong to the same species and live in the same geographical area.
The conditions in the environment that can change an organisms appearance e.g. diet, food supply, climate changes, diseases, predators.
Reproduction involving only one parent that creates genetically identical offspring
Type of variation in which there is a complete range of measurements from one extreme to the other e.g. human height.
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