Download Chapter 10 Section 3 Notes Answer Key

Chapter 10 Section 3 Notes
I. DNA
A. DNA- a chemical that contains information an
organism needs to grow and
function
1. Watson and Crick made and accurate model of
DNA in 1953
2. The structure of DNA is similar to a twisted ladder.
a. The sides of the ladder are made up of sugarphosphate molecules.
b. The rungs of the ladder are made of nitrogen
bases.
3. Before a cell divides, its DNA duplicates itself by
unwinding and separating its sides, then each side
becaomes a pattern on which a new side forms
B. Genes- sections of DNA on a chromosome
1. contains instructions for making specific proteins
2. RNA carries the codes for making proteins to the
nucleus for the ribosomes in the cytoplasm
a. Messenger RNA carries the code that directs
the order in which the amino acid bond.
b. Ribosomal RNA makes up ribosomes where
proteins are built
c. Transfer RNA brings amino acids to the
ribosomes to build the protein
3. Cells use only the genes that direct the making of
proteins needed by the cell
C. Mutations- any permanent change in the DNA
sequence of a cell’s gene or chromosome
1. Can be caused by outside factors like X-rays,
sunlight, and some chemicals
2. A can in a gene or chromosome can change the
traits of an organism