The process when a cell with a nucleus divides to form two nuclei
Mitosis
Why do cells divide?
- To MAINTAIN a high ratio of surface area to volume
- To REPLACE dead or damaged cells
- To DIFFERENCIATE e.g. embryo development
- To INCREASE the size of the organism
What are the end results of mitosis?
- Two new daughter cells (identical, both ½ size of OG cell, clones)
- Two diploid (2N) cells
☆ How we know DNA is the genetic material ☆
1944 - Avery, McCarty, Macleod (proved DNA carried info for inheritance)
1952 - Hershey & Chase (used viruses to provide evidence that genes were made of DNA)
1966 - Gobind Khorhana (helped to show how DNA codes for characteristics –> does with the order of the bases)
☆ History of discovery of DNA ☆
1869 - Miescher discovered nuclein (first to identify DNA as distinct molecule)
1909 - Levene discovered DNA bases A, C, G, T
1944 - Avery, MacLeod, McCarty discovered DNA carried info for inheritance
1952 - Rosalind Franklin, Maurice Wilkins took pictures of structure of DNA
1953 - Watson & Crick with pictures made double helix structure
1966 - Gobind Khorhana able to produce proteins, amino acid sequences that revealed DNA genetic code
☆ Describe the structure of DNA ☆
Shape: double helix
Backbone: Alternating phosphate & deoxyribose sugar
Rungs: nitrogen bases joined by hydrogen bonds
Base Pairing rule: A -> T
C -> G
5’ –> 3’ or 3’ –> 5’
DNA serves as a ______
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