Structure of RNA Single strand of nucleotides bonded
Structure of RNA Single strand of nucleotides bonded into a chain – Each nucleotide contains • Ribose, sugar • Phosphate • Nitrogen base: adenine, guanine, cytosine or uracil • Adenine pairs with Uracil/ Cytosine pairs with Guanine
RNA Types • Messenger RNA- carries the code for making proteins • Ribosomal RNA- combine with a ribosome • Transfer RNA- brings the amino acid to the ribosome
TRANSCRIPTION • When DNA gives RNA the code with the help of enzymes!!
Section 12 -3 Transcription Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only) RNA polymerase RNA Go to Section: DNA
• The sugar in RNA is _______, the sugar in DNA is ____. a. deoxyribose, ribose b. ribose, deoxyribose c. ribose, phosphate d. ribose, uracil
Once transcription is complete, DNA is not necessary for protein synthesis A. True B. False
RNA is synthesized on a DNA template in a process called ____, which utilizes the enzyme____. A. B. C. D. translation, RNA polymerase transcription, DNA polymerase replication , DNA polymerase
• Given the following DNA strand, which of the following is its complementary m. RNA? GGACTGATT a. CCTGACTAA b. TTAGTCAGG c. GGACTGATT d. CCUGACUAA
• Which of the following takes the genetic code to the cytoplasm: a. DNA c. t. RNA b. m. RNA d. deoxiribose
TRANSLATION • Process of assembling proteins from the information encoded in RNA • m. RNA leaves the nucleus and goes to the ribosome – the codon ( 3 bases in sequence on the m. RNA) • t. RNA, transfer RNA leaves the nucleus and picks up an amino acid – the anticodon is the compliment to the codon on m. RNA
Section 12 -3 Translation Nucleus Messenger RNA is transcribed in the nucleus. Phenylalanine t. RNA The m. RNA then enters the cytoplasm and attaches to a ribosome. Translation begins at AUG, the start codon. Each transfer RNA has an anticodon whose bases are complementary to a codon on the m. RNA strand. The ribosome positions the start codon to attract its anticodon, which is part of the t. RNA that binds methionine. The ribosome also binds the next codon and its anticodon. Ribosome Go to Section: m. RNA Transfer RNA Methionine m. RNA Lysine Start codon
Section 12 -3 Translation (continued) The Polypeptide “Assembly Line” The ribosome joins the two amino acids— methionine and phenylalanine—and breaks the bond between methionine and its t. RNA. The t. RNA floats away, allowing the ribosome to bind to another t. RNA. The ribosome moves along the m. RNA, binding new t. RNA molecules and amino acids. Lysine Growing polypeptide chain Ribosome t. RNA m. RNA Completing the Polypeptide m. RNA Go to Section: Ribosome Translation direction The process continues until the ribosome reaches one of the three stop codons. The result is a growing polypeptide chain.
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• The three nucleotides sequence on MRNA is called a: • a. t. RNA b. gene • c. triplet d. codon
Which site of the t. RNA molecule binds to the m. RNA molecule? • a. anitcodon • b. codon • c. amino acid • d. 5 prime end
• Translation occurs: a. at the ribosome b. in the nucleus c. both d. neither
START & STOP SIGNALS • To start the protein synthesis the codon AUG must be present • To stop the protein synthesis there’s a stop codon UAA, UGA, UUC
• Three nucleotides code for one amino acid • Ex: UUG codes for Leucine • There are only 20 Amino Acids that can combine together to form proteins. #ONLY 20 Amino ACIDS. . WOW#
Practice Use your book page 338
Practice Answers
- Slides: 20