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From DNA to Protein Chapter 5. Ricin and your Ribosomes.

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Presentation on theme: "From DNA to Protein Chapter 5. Ricin and your Ribosomes."— Presentation transcript:

1 From DNA to Protein Chapter 5

2 Ricin and your Ribosomes

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4 DNA and RNA DNA has one function: It permanently stores a cell’s genetic information, which is passed to offspring. RNAs have various functions. Some serve as disposable copies of DNA’s genetic message; others are catalytic.

5 DNA template mRNA protein stop Gly Glu Amino acid Transcription Translation

6 RNA in Protein Synthesis 2 Different Kinds of RNA: Messenger RNA (mRNA) Messenger RNA (mRNA) Contains information transcribed from DNA Transfer RNA (tRNA) Transfer RNA (tRNA) Delivers amino acids to ribosomes

7 Gene Expression Gene expression Gene expression A multistep process in which genetic information is converted into a structural or functional part of a cell or body

8 Transcription: DNA to RNA Transcription: DNA to RNA RNA polymerase assembles RNA by linking RNA nucleotides into a chain RNA polymerase assembles RNA by linking RNA nucleotides into a chain

9 DNA template mRNA Transcription Transcription: DNA to RNA

10 Base-Pairing in DNA Synthesis and Transcription

11 Fig. 14-5a, p. 218

12 Fig. 14-7, p. 220 gene exonintronexonintronexon DNA transcription into RNA cap poly-A tail mRNA 5’ 3’ snipped out mRNA Pre- Post-Transcriptional Modifications

13 mRNA – The Messenger Codon-A sequence of 3 mRNA nucleotides that codes for a specific amino acid Codon-A sequence of 3 mRNA nucleotides that codes for a specific amino acid The order of codons in mRNA determines the order of amino acids in a polypeptide chain The order of codons in mRNA determines the order of amino acids in a polypeptide chain

14 Genetic Information From DNA to mRNA to amino acid sequence codon

15 Translation 2 subunits Ribosomes made of rRNA & proteins

16 Codons of the Genetic Code

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18 Common Mutations Base-pair-substitution Base-pair-substitution Deletion or insertion Deletion or insertion

19 Fig. 14-13, p. 224 THREONINEPROLINEGLUTAMATE LYSINE THREONINEPROLINEVALINEGLUTAMATELYSINE THREONINEPROLINEGLYCINEARGININE c. Frame shift b. Base pair substitution a.Normal Hemoglobin chain

20 What Causes Mutations? 1. Spontaneous mutations Uncorrected errors in DNA replication Uncorrected errors in DNA replication 2. Harmful environmental agents a. UV radiation b. chemicals

21 Inherited Mutations Mutations in somatic cells of sexually reproducing species are not inherited Mutations in somatic cells of sexually reproducing species are not inherited Mutations in a gamete may be inherited, with evolutionary consequences Mutations in a gamete may be inherited, with evolutionary consequences

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