RNA and Transcription

DNA Review

• What is DNA and what role does it serve in our bodies?

• What is the shape of DNA?• What macromolecule makes up DNA?

DNA

• We’ve mentioned before that DNA contains our genes and genetic material, but we have yet to discuss how DNA uses those genes.

• Today we are going to begin our discussion into protein synthesis.

Today’s Objectives

• 1. Review DNA and genetic code.• 2. Discuss RNA.• 3. Discuss the process of transcription

Genetic Code

• The main function of genes in the body is controlling the production of proteins in your cells.

• Proteins help to determine how traits are expressed in an organism.

• This can include hair color, body size, height, ear size, etc….

Genetic Code

• What part of the DNA do you think relates to the genetic code?

• Look at the figure to the right as a hint.

Genetic Code

• The genetic code can be found in the four nitrogen bases.

• Adenine (A), Thymine (T), guanine (G), and Cytosine (C).

• Genes are sections of DNA molecules that contain information to code on specific protein.

• The order in of the nitrogen bases along a gene forms genetic code that specifies what type of protein will be produced.

RNA

• RNA is another macromolecule found in the body.

• What role do you think RNA serves in the body?

• Take a few minutes to discuss this at your table.

• In a few minutes we’ll discuss RNA as a class.

RNA

• RNA stands for ribonucleic acid.• Serves as a “messenger” in the cell.• RNA carries the genetic code from the nucleus into the

cytoplasm.• RNA is similar to DNA but is different from DNA in three ways:– RNA is single stranded instead of double stranded like DNA– RNA also contains a different sugar from the sugar found in

DNA– RNA contains the nitrogen base called Uracil (U) instead of

thymine.

Types of RNA

• There are several types of RNA found in the body: mRNA and tRNA.

• mRNA stands for messenger RNA copies the coded message from the DNA in the nucleus and carries the message to the cytoplasm.

• mRNA is created in the nucleus from your cells DNA.

• How could RNA be created from DNA?

Transcription

• Transcription is the first step of protein synthesis.

• During transcription, the DNA strand unzips and mRNA will copy it’s strand from the DNA.

Transcription

• Now you guys will serve a role as RNA polymerase.

• You will be given a worksheet on transcription and on this worksheet you will need to code RNA from strands of DNA and answer a few other questions related to transcription.