RNA Another Nucleic Acid RNA Structure RNA is

RNA Another Nucleic Acid

RNA Structure • RNA is the second type of nucleic acid found in a cell. • There are 3 different types of RNA • Structure of RNA: • Long chain of nucleotides • 5 -carbon sugar called ribose • Phosphate • Nitrogen bases- Adenine, Guanine, Cytosine and Uracil (instead of Thymine) • Just a single strand

Function of RNA • The function of RNA is to carry the code from DNA in the nucleus to the ribosomes in the cytoplasm (where the code will be used to make proteins).

✓ Quick Check • Compare the details of DNA to RNA Feature DNA RNA # of strands 2 1 Type of sugar Deoxyribose Ribose Nitrogen bases A, T, G, C A, U, G, C Location in cell Nucleus → Ribosome in cytoplasm Number of forms 1 3 Job description Carries genetic information Take info from DNA to the ribosomes to make proteins

Types of RNA • Messenger RNA (m. RNA)- this is the piece of RNA that takes the code (“message”) from the DNA to the ribosome. • Transfer RNA (t. RNA)- this RNA brings (“transfers”) amino acids from the cytoplasm to the ribosome/ m. RNA. • Ribosomal RNA (r. RNA)- this is the structural part of a ribosome (a ribosome is only protein and RNA)

Types of RNA

Transcription • Transcription is the process in which a part (gene) of the DNA is copied into m. RNA. • Players • Piece of DNA • Nucleotides • Enzyme- RNA polymerase

Transcription • What happens: • RNA polymerase finds a sequence called the promoter, binds to the DNA and unzips the strands • RNA polymerase “reads” one strand of the DNA and adds the appropriate complementary RNA nucleotides • The product= a single strand of m. RNA

✓ Quick Check • 1. The three types of RNA are m. RN _______t. RNA , A r. RNAand _______ • 2. The process of making RNA from DNA is called transcripti ________. on • 3. m. RNA has to be made from DNA because the DNA cannot leavenucleu the _____ and the s proteins coded for by the DNA areribosome made by the cytoplas ______ which are found sin the m _______. • 4. If the sequence of DNAUCAUCCAG is AGTAGGTCA, what is the m. RNA made from it? U

The Genetic Code • Proteins are continuously made by linking together amino acids. • There are 32 different amino acids. • The sequence of nitrogen bases in DNA and m. RNA determine the order of amino acids in protein. • Codon= the sequence of 3 nucleotides that codes for a specific amino acid. • Anti-codon= the complementary sequence to the codon; it is found on the t. RNA

Codon Chart

✓ Quick Check • Use your amino acid chart to identify the amino acid that goes with each codon. Methionine (start) • 1. AUG __________ Stop • 2. UGA __________ Lysine • 3. AAA __________ • 4. GAG __________ Glutamate • 5. UCA __________ Serine • 6. UCC __________ Serine

Translation • The sequence of nucleotides in m. RNA provides the instructions to the ribosomes for putting together a protein. • Translation- the decoding of an m. RNA message into an amino acid chain (protein). • Parts involved: • m. RNA • Ribosome • t. RNA • Amino acids

Translation • How it’s done: • m. RNA attaches to a ribosome in the cytoplasm • The codon on the m. RNA is “read” by the ribosome. • The ribosome brings in the correct anti-codon with an amino acid attached. • The anti-codon of the t. RNA matches up with the codon on the m. RNA.

Translation • The second codon is “read” and the ribosome brings in the next t. RNA. • A peptide bond forms between the amino acids on the 2 t. RNA’s in the ribosome. • The first t. RNA loses its amino acid and it leaves the ribosome. • The ribosome slides along continuing the process until a STOP codon is reached.

✓Quick Check • Complete the remaining Quick Check in your notes. We will go over the answers in 15 minutes. • http: //www. online-stopwatch. com/countdowntimer/