Introns
transcription
translation
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Fig. 9.17 Processing eukaryotic mRNA
Protect from degradation and facilitate translation
Different combinations of exons can generate different polypeptides via alternative splicing
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6. The polypeptide chain grows until the protetin is completed.
Amino acid
Completed polypeptide
tRNA
5’ Ribosome moves toward 3’ end
Fig. 9.18 How protein synthesis works in eukaryotes
Cytoplasm
5. tRNAs bring their amino acids in at the A site of the ribosome. Peptide bonds form between amino acids at the P site, and tRNAs exit the ribosome from the E site.
Ribosome
DNA Nuclear membrane 3’ 5’ 5’ 5’ 3’ Primary RNA transcript 5’ Cap mRNA Poly-A tail mRNA 3’ 2. Introns are excised from the RNA transcript, and the remaining exons are spliced together, producing mRNA Small ribosomal subunit Nuclear pore
4. tRNA molecules become attached to specific amino acids with the help of activating enzymes. Amino acids are brought to the ribosome in the order dictated by the mRNA.
3’ RNA polymerase 1. In the cell nucleus, RNA polymerase transcribes RNA from DNA
Cap
3’ Poly-A tail Introns
Exons
Large ribosomal subunit
3. mRNA is transported out of the nucleus. In the cytoplasm, ribosomal subunits bind to the mRNA
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Fig. 9.23
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9.9 Mutation
Mutation and recombination provide the raw material for evolution Evolution can be viewed as the selection of particular combinations of alleles from a pool of alternatives Mutations in germ-line tissues can be inherited Mutations in somatic tissues are not inherited
Copyright ©The McGraw-Hill Companies,
translation
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Fig. 9.17 Processing eukaryotic mRNA
Protect from degradation and facilitate translation
Different combinations of exons can generate different polypeptides via alternative splicing
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display
6. The polypeptide chain grows until the protetin is completed.
Amino acid
Completed polypeptide
tRNA
5’ Ribosome moves toward 3’ end
Fig. 9.18 How protein synthesis works in eukaryotes
Cytoplasm
5. tRNAs bring their amino acids in at the A site of the ribosome. Peptide bonds form between amino acids at the P site, and tRNAs exit the ribosome from the E site.
Ribosome
DNA Nuclear membrane 3’ 5’ 5’ 5’ 3’ Primary RNA transcript 5’ Cap mRNA Poly-A tail mRNA 3’ 2. Introns are excised from the RNA transcript, and the remaining exons are spliced together, producing mRNA Small ribosomal subunit Nuclear pore
4. tRNA molecules become attached to specific amino acids with the help of activating enzymes. Amino acids are brought to the ribosome in the order dictated by the mRNA.
3’ RNA polymerase 1. In the cell nucleus, RNA polymerase transcribes RNA from DNA
Cap
3’ Poly-A tail Introns
Exons
Large ribosomal subunit
3. mRNA is transported out of the nucleus. In the cytoplasm, ribosomal subunits bind to the mRNA
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Fig. 9.23
Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display
9.9 Mutation
Mutation and recombination provide the raw material for evolution Evolution can be viewed as the selection of particular combinations of alleles from a pool of alternatives Mutations in germ-line tissues can be inherited Mutations in somatic tissues are not inherited
Copyright ©The McGraw-Hill Companies,