By the beginning of the 1900’s, it was known that the chromosomes carry the genetic or hereditary information.
Heredity is controlled mostly by genes and to some degree by the environment.
For example, all plants can make chlorophyll (which makes them green). There is a gene that gives them this ability. If a seed is grown in the dark, the leaves will come up white, not green (environment played a role.)
It is believed that the base-pair sequence (order) of the gene controls cellular activity by specifying a protein.
The nitrogenous bases are like letters in an alphabet. The DNA molecule is a sequence of bases that spell out words in the DNA code. The code is eventually converted into an amino acid sequence to make the appropriate proteins needed by the organism.
Identical copies of an organism without fertilization.
Egg cell remove monoploid nucleus add diploid nucleus from a mammary cell or any other cell of an adult organism egg cell with new nucleus is transplanted into uterus of another organism new individual produced is identical to original.
Example: Dolly (sheep) cloned in 1997 by Dr. Ian Wilmut
__________________________________________________________________________________________________________________________________ Molecule A was made using Recombinant DNA. A human gene for insulin was Combined with the DNA of a Bacterial cell.