Class Notes 3 RNA and the Central Dogma. I. Function of DNA A.The DNA is a set of instructions for the ribosomes to follow as they make proteins (protein.

Class Notes 3Class Notes 3

RNA and the Central DogmaRNA and the Central Dogma

I. Function of DNAI. Function of DNA

A.A. The DNA is a set of instructions for the The DNA is a set of instructions for the ribosomes to follow as they make ribosomes to follow as they make proteins (protein synthesis)proteins (protein synthesis)

B.B. However the DNA is located in the However the DNA is located in the nucleus and can’t get out.nucleus and can’t get out.

C. The ribosomes are located outside of the C. The ribosomes are located outside of the nucleus in the cytoplasm.nucleus in the cytoplasm.

II. Central DogmaII. Central Dogma

Question: How can the DNA instructions get Question: How can the DNA instructions get to the ribosomes??????to the ribosomes??????

Answer: Transcription!!!!!!!!!!!Answer: Transcription!!!!!!!!!!!

A.A. DNA is transcribed (copied) into a type of DNA is transcribed (copied) into a type of RNA called mRNA.RNA called mRNA.

B.B. The mRNA can leave the nucleus and go The mRNA can leave the nucleus and go to the ribosome to be translated into a to the ribosome to be translated into a sequence of amino acids called a sequence of amino acids called a protein.protein.

C.C. DNADNA→RNA→protein is called the central →RNA→protein is called the central dogma of molecular biologydogma of molecular biology

III. RNAIII. RNA

A.A. RNA is a nucleic acid, like DNA except:RNA is a nucleic acid, like DNA except:

1.1. RNA is single stranded, DNA is _______ RNA is single stranded, DNA is _______ _________._________.

2.2. RNA has the sugar ribose, DNA has the RNA has the sugar ribose, DNA has the sugar ___________.sugar ___________.

3.3. RNA has the nitrogen bases U (uracil), RNA has the nitrogen bases U (uracil), A, C and G, DNA has __ , __ , __ &__.A, C and G, DNA has __ , __ , __ &__.

IV. Types of RNAIV. Types of RNA

A.A. There are 3 types of RNA.There are 3 types of RNA.

1.1. mRNA- messenger, is a copy of DNA mRNA- messenger, is a copy of DNA that can go to the ribosomethat can go to the ribosome

2.2. rRNA – ribosomal, links the amino acidsrRNA – ribosomal, links the amino acids

3.3. tRNA – transfer, brings amino acids to tRNA – transfer, brings amino acids to the ribosomesthe ribosomes

SummarySummary

Why is mRNA needed for protein Why is mRNA needed for protein synthesis?synthesis?

What are the differences between DNA What are the differences between DNA and RNA? and RNA?