From DNA to Protein Main Idea: DNA codes for RNA, which guides protein synthesis. Proteins are key cell structures and regulators of cell function. -Ex. Providing muscle tissue, breakdown & digesting food (enzymes).

RNA vs. DNA RNA is a nucleic acid, like DNA Three differences: –1. Single strand not double –2. Sugar in RNA is ribose instead of deoxyribose. –3. Four bases: A, G, C, U (Uracil replaces Thiamine).

RNA RNA are the workers for Protein Synthesis. 3 types: mRNA, rRNA, & tRNA

mRNA messenger RNA brings information from DNA to the cell’s factory floor, the cytoplasm.

rRNA ribosomal RNA Ribosomes made of mRNA clamp onto the mRNA & use its information to assemble the amino acids in the correct order.

tRNA transfer RNA tRNA is the supplier. It transports the amino acids to the ribosomes to be assembled into a protein.

Transcription 1 st step of protein synthesis In the nucleus enzymes make an RNA strand in a process called transcription. Transcription is like DNA replication except it results in a single strand rather than a double strand. See pg. 296 in text.

Transcription

Process begins as RNA polymerase initiates synthesis and unzips DNA. As DNA unzips, free RNA nucleotides pair with complimentary DNA nucleotides on one strand. When the process of base pairing is completed, mRNA strand breaks away as the DNA strand rejoin. The mRNA leaves the nucleus and enters the cytoplasm.

Animation Transcription