DNA RNA and Chapter 4 3 DNA Video

DNA RNA and Chapter 4 -3 DNA Video 15 min

DNA l Deoxyribonucleic acid is a molecule that looks like a spiral staircase.

1. The sides (handrails) are made of sugar (S) and phosphate (P) molecules. S- -S P- -P S- -S P- -P

2. The sides are connected with nitrogen bases. 3. There are four types of nitrogen bases in DNA -Adenine (A) -Thymine (T) -Cytosine (C) -Guanine (G) 4. Adenine always pairs with Thymine and Cytosine always pairs with Guanine. -AT-CG-

5. When they are connected they look something like this. S- T A P- C G -P S- T A -S P- T A -P S- G C -S P- G C -P S- T P- C G -P T A -S -S -S

6. DNA REPLICATION a) The DNA strand unzips and new bases fill in the gaps. b) This process allows the DNA to make an exact copy of itself. c) This process takes place during the “S” phase of interphase. d) Click on the hyperlinks below to see how this process works.

RNA 1. Ribonucleic Acid (RNA) is like DNA but is only a single stranded molecule. 2. The base Uracil replaces Thymine. Adenine (A) then pairs with Uracil. 3. The four RNA bases are: - Cytosine (C) (G) Guanine - Adenine (A) (U) Uracil -

PROTEIN SYNTHESIS 1. RNA is used to transfer the genetic code that is used in making protiens. 2. There are two kinds of RNA. 3. a) Messenger RNA (m. RNA) 4. b) Transfer RNA (t. RNA) 5. 3. m. RNA carries the genetic code from the DNA to the t. RNA. 6. 4. t. RNA receives the genetic code from the m. RNA and assembles the proteins with help from the ribosome. 7. 5. Click on the hyperlink below to see how this is done. http: //www. lewport. wnyric. org/JWANAMAKER/anim ations/Protein%20 Synthesis%20 -%20 long. html

Remember Me?

GENETIC CODE CHART Use this genetic code chart to find out which amino acids are called for by the m. RNA codons.

MUTATIONS 1. Sometimes mistakes are made during the transfer of genetic code from: a) DNA to DNA b) DNA to m. RNA c) m. RNA to t. RNA 2. We will talk about mutations in a later chapter. * In the meantime if you would like to practice DNA replication or protein synthesis, check out this web site from Glaxo. Smith. Kline (GSK) http: //genetics. gsk. com/kids/dna 01. htm Blue/Green Frog Mutation http: //www. youtube. com/watch? v=x. BH 3 9 g-4 el. Y