Presentation on theme: "1 Review How does a cell interpret the genetic code Explain What are codons and anticodons 2 Review What happens during translation Compare and Contrast."— Presentation transcript:
1 1 Review How does a cell interpret the genetic code Explain What are codons and anticodons 2 Review What happens during translation Compare and Contrast How is protein synthesis different from DNA replication 3 Review Why is the genetic code considered universal Infer In what way does controlling the proteins in an organism control it’s characteristics 4 Choose one component of translation. Write a question about that component and use it to form a hypothesis that could be tested in an experiment
2 Ch 13 RNA and Protein Synthesis 13.2 Ribosomes and Protein Synthesis
3 Proteins are made from long chains of amino acids or polypeptides 20 different amino acidsOrder of amino acids make proteins different.
4 Codon Each three-letter “word” in mRNA Consists of three consecutive bases that specify a single amino acid.
5 How to Read CodonsFour different bases in RNA, so 64 possible three- base codons (4×4×4 = 64)To read a codon, start at the middle of the circle and move outward.
8 Translation Decoding of an mRNA message into a protein From RNA to proteinDifferent languages.
9 Translation StepsmRNA is transcribed in the nucleus and then enters the cytoplasm for translation.
10 Ribosome attaches to an mRNA molecule Ribosome reads each codon of mRNADirects tRNA to bring the specified amino acidRibosome then attaches each amino acid to the growing chain.
11 tRNA has three unpaired bases or anticodon which is complementary to one mRNA codon Codon AUGAnticodon UAC.
12 Next codon is UUCtRNA molecule with an AAG anticodon brings the amino acid to ribosome.
13 Ribosome helps form a peptide bond between 1st and 2nd amino acid Bond between tRNA molecule and amino acid is brokentRNA shifts to 3rd site.
14 Ribosome moves over one codon New tRNA enters ribosomeProcess repeats itself.
15 Translation continues until a stop codon Ribosome release polypeptide and mRNA.
16 Molecular Basis of Heredity Most genes contain instructions for assembling proteins.
17 Proteins Can Be enzymes Produce pigment or odor Regulate growth Trigger developmentOperate cell parts.
18 Gene Expression What DNA actually ends up doing How the genes gets expressed or shown.
19 Genetic code is nearly universal in all living organisms.
20 A certain gene has the following base sequence GACAAGTCCACAATC Write this sequence downFrom left to right, write the sequence of mRNA molecule transcribed from this geneUsing the figure on pg. 311, read the mRNA from left to right and write down the amino acid sequenceRepeat step 3 reading the codons from right to left.
21 Analyze and ConcludeApply Concepts Why did steps 3 and 4 produce different polypeptidesInfer Do cells usually decode nucleotides in one direction only or in either direction