Science 9: Unit 1 - Biodiversity

Topic 2.2 - Transmitter of Genetic Code

Genetics: The study of how characteristics are passed from one generation to the next

DNA (Deoxyribonucleic acid): A molecular blueprint for a living thing. Found in the nucleus. Shaped like a helix. It is made up of four molecules:

- Adenine

- Thymine

- Guanine

- Cytosine

These molecules arrange themselves in different orders like an alphabet, called the Genetic Code.

Chromosomes: Packets of information that determine the traits of an organism. Humans have 46 pairs(23 individual)

Genes: A segment of DNA that are responsible for inheritable characteristics.

Alleles: Variations of possible DNA sequences in genes (Brown: Dominant, Blue: Recessive)

Mitosis: 1 division, ends with two new cells that are identical with all chromosomes. This happens in growth and repair cells.

Steps to Mitosis:

Prophase - DNA doubles

Metaphase - Lines up in middle

Anaphase - Pulls DNA apart and splits

Telephase - Two new cells

Advantages - Fast, No partner needed, Less energy needed

Disadvantages - Identical, less variation

Meiosis: 2 divisions, ends with four cells with random amounts of half DNA. Only happens in sex cells

Steps to Meiosis:

Prophase I - DNA doubles and mixes

Metaphase I - Lines up in middle

Anaphase I - Pulls DNA apart and splits

Telephase I - Two new cells

Prophase II - DNA doubles and mixes

Metaphase II - Lines up in middle

Anaphase II - Pulls DNA apart and splits

Telephase II - Two new cells

Advantages - More variation

Disadvantages - More energy and time needed, Requi

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Use this to study for tests.