DNA – RNA – Protein Synthesis Objectives: F1-Identify the components of DNA, describe how information for specifying traits is carried in DNA, & recognize that components that make up the genetic code are common to all organisms F2 - Explain the purpose & process of transcription & translation using models of DNA & RNA, describe the role of DNA & RNA during protein synthesis, & recognize that gene expression is a regulated process

III. DNA Structure and Function A. Description - deoxyribonucleic acid is a polymer made up of repeating monomers of nucleotides

B. Structure 1. Double stranded 2. Helix

- subunits of DNA; 3 parts 3. Nucleotides - subunits of DNA; 3 parts

* PHOSPHATE group * nitrogen bases (1of4) * SUGAR - deoxyribose Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Why DNA is often compared to a ladder? DNA is similar to a ladder: the rails of a ladder represent the sugar-phosphate backbone of DNA, and the rungs of a ladder represent the nitrogen base. How is a ladder different from DNA? DNA is twisted while a ladder is flat and that a “rung” in the DNA molecule is made of two bases, while the ladder’s rung is a single unit. The P of one nucleotide is bonded to the sugar of another nucleotide. purines pyrimidines

4. Complementary Base Pairing A purine is always paired with a pyrimidine. A-T C-G

Location Remains in the nucleus

D. Function - DNA determines an organism’s traits by controlling the manufacturing of proteins. The sequencing of nucleotides forms unique genetic information.

E. Involved with theses processes: 1. Replication - Copying process by which a cell duplicates its DNA 2. Transcription

III. RNA Structure and Function A. Description – ribonucleic acid; similar to DNA (messenger RNA & transfer RNA)

B. Structure 1. Single stranded 2. mRNA – straight line tRNA – t shaped

3. Made up of subunits called Nucleotides * phosphate group * sugar - ribose * nitrogen base (1of4) - A - G - Uracil (U) - C 4. Base Pairing A-T G-C U-A C-G

Location mRNA – travels from the nucleus to ribosomes tRNA – through sites on the ribosome

D. Function mRNA – carries the genetic information out of the nucleus for protein synthesis tRNA – decode the information by transferring the amino acid to the ribosome

E. Involved with theses processes: 1. Transcription – mRNA is made from DNA in the nucleus 2. Translation – proteins are made from mRNA with the help of tRNA at ribosomes

Etymology Transcription: trans- (L. across) + -scription (SCRIBERE, to write) Translation: : (L. TRANSLATUS carried across)

Peptide bond between the amino acids (polypeptide) Peptide bond between the amino acids

DNA Base Pairing TCG AAC TGG AGC TTG ACC You try: CCA GAT TGA GGT CTA ACT

DNA to RNA Base Pairing DNA - TCG AAC TGG RNA - AGC UUG ACC You try: DNA - CCA GAT TGA RNA - GGU CUA ACU