Presentation on theme: "Or…how our bodies make proteins!"— Presentation transcript:
1 Or…how our bodies make proteins! PROTEIN SYNTHESISOr…how our bodies make proteins!
2 What do these Chinese symbols say? Transcribe to English alphabet:Translate to English words:
3 The function of DNAThe DNA molecule contains all your hereditary information in the form of genesA gene is a coded section of DNA; it tells our cells how to build specific proteinsGenes code for EVERYTHING our body needs and does (saliva, bones, eye shape)Because DNA is so large, it is stuck inside the nucleusIt needs a messenger to move the information from nucleus to protein production locations (ribosomes!)
4 DNA needs RNA!RNA is a nucleic acid messenger between DNA and ribosomes3 differences between DNA and RNA:RNA has ribose sugarRNA is single strandedRNA contains a nitrogen base called uracil (U) instead of thymine.
5 DNA RNA Double stranded molecule Contains thymine Contains deoxyribose sugar- Found only in nucleusSingle stranded moleculeContains uracilContains ribose sugar- Found in nucleus and cytoplasmMade of nucleotides- Contain adenine, guanine, and cytosine
6 Does this diagram represent DNA or RNA? …how can you tell?
8 3 types of RNA Messenger RNA (mRNA): Ribosomal RNA (rRNA): copies DNA in the nucleus and carries the info to the ribosomes (in cytoplasm)Ribosomal RNA (rRNA):makes up a large part of the ribosome; reads and decodes mRNATransfer RNA (tRNA):carries amino acids to the ribosome where they are joined to form proteins
9 Protein synthesisProtein synthesis is the assembly of amino acids (by RNA) into proteinsInvolves two steps:1. Transcription – copying DNA code into mRNA2. Translation – reading the mRNA code and assembling amino acids into a polypeptide chain (protein)
10 Chinese characters transcribed to English alphabet: TranscriptionPerformed in nucleus by mRNAmRNA “reads” single DNA strand and forms the complementary copyChinese characters transcribed to English alphabet:
11 How transcription works DNA strand splits, exposing the active strandComplementary mRNA nucleotides line up opposite the active strand, forming mRNAmRNA leaves the nucleusTranscription demo
12 Transcribed Chinese words translated to English words: TranslationTranslation occurs in ribosomes (in cytoplasm)All three types of RNA work together during translation to produce proteinsTranscribed Chinese words translated to English words:
13 Decoding mRNA (translation) The sequence of bases in an mRNA molecule serves as instructions for the order in which amino acids are joined to produce a polypeptideRibosomes decode the instructions by using codons, sets of 3 bases that each code for 1 amino acidEach codon is matched to an anticodon, or complementary sequence on the tRNA to determine the order of the amino acidsTranslation demo
14 Using a codon chartA codon chart is used to determine the sequence of the amino acids in the polypeptideThe sets of 3 mRNA bases (codons) are used to find the amino acid
15 Decoding PracticeFor the following DNA examples, first give the appropriate mRNA sequence, then identify the amino acid sequence (remember: U replaces T in mRNA)Example 1:DNA: TAC GCA TGG AATmRNA: AUG CGU ACC UUAAmino Acids: Met Arg Thr LeuExample 2:DNA: CGT GGA GAT ATTmRNA: GCA CCU CUA UAAAmino Acids: Ala Pro Leu stopTranslation Review