Bell Work 1/11/2010 What is the name of the enzyme involved in DNA Replication?

Protein Synthesis

Review

DNA O O=P-O OPhosphate Group Group N Nitrogenous base (A, T, G, C) (A, T, G, C) CH2 O C1C1 C4C4 C3C3 C2C2 5 Sugar Sugar(deoxyribose)

DNA - double helix P P P O O O P P P O O O G C TATA

RNA Function: obtain information from DNA & synthesizes proteins

3 differences from DNA 1.Single strand instead of double strand 2.Ribose instead of deoxyribose as its sugar 3.Uracil instead of thymine 1.U instead of T

A – T C – G Example: ATGACT  TACCGA RNA DNA A – U C – G Example: ATGACT  UACGGA

RNA O O=P-O OPhosphate Group Group N Nitrogenous base (A, U, G, C ) (A, U, G, C ) CH2 O C1C1 C4C4 C3C3 C2C2 5 Sugar Sugar (ribose) (ribose)

3 types of RNA 1.Messenger RNA (mRNA)- copies information from DNA for protein synthesis

3 types of RNA 2. Transfer RNA (tRNA)- collects amino acids for protein synthesis

3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes

RNA Polymerase- enzyme for transcription RNA polymerase pairs RNA nucleotides to DNA strands. Uracil replaces thymine (U instead of T)

Transcription - mRNA is made from DNA & goes to the ribosome Translation - Proteins are made from the message on the mRNA

Transcription In order for cells to make proteins, the DNA code must be transcribed (copied) to mRNA. Why? –DNA cannot leave the nucleus. Proteins are made in the cytoplasm. mRNA serves as a “messenger” and carries the protein building instructions to the ribosomes in the cytoplasm. The mRNA carries the code from the nucleus to the ribosomes.

Questions Why does transcription need to occur? Why does DNA need to be converted into RNA?

Step one of Transcription RNA Polymerase unwinds and unzips the DNA double helix.

Step two of Transcription RNA polymerase adds on free- floating nucleotides

Step Three of Transcription RNA detaches from the template DNA

TRANSCRIPTION EXAMPLE DNA Sequence into mRNA TAC CGG ATC CTA GGA TCA AUG GCC UAG GAU CCU AGU

Transcription Animation animations.blogspot.com/2009/11/gene- transcription-animation.htmlhttp://biology- animations.blogspot.com/2009/11/gene- transcription-animation.html

TRANSCRIPTION EXAMPLE Write the DNA molecule below as RNA DNA Sequence into mRNA 1. ACG 2. GGG TAG CCA 3. CGG ATC CTA 4. GGA TCA ACG GCC 5. TAG GAU GAT CAT 4. CCA AGT TAG ATG TTA A= U C= G