8: DNA to Protein
- Page ID
- 188611
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)The process by which genetic information in DNA is used to produce proteins is known as gene expression (the series of cellular processes that convert the information encoded in a gene into a functional product, usually a protein). Gene expression occurs through two major steps: transcription (the process of copying a segment of DNA into RNA) and translation (the process in which the information in messenger RNA is used to assemble a protein).
Although all living organisms rely on these same fundamental processes, the details of gene expression differ between prokaryotic cells and eukaryotic cells. These differences influence how genes are organized, how RNA molecules are processed, and how proteins are produced within the cell.
- 8.1: Prokaryotic Transcription
- This page covers prokaryotic transcription, highlighting its role in gene expression through RNA synthesis from DNA. It explains the organization of genes in operons for coordinated expression and details the initiation process with RNA polymerase and sigma factors at promoters. The page also addresses the coupling of transcription with translation and describes termination mechanisms involving hairpin structures or rho factors, leading to RNA release for further gene expression.
- 8.2: Prokaryotic Translation
- This page explains the translation process in prokaryotic cells, highlighting the roles of mRNA, tRNA, and ribosomes. It details three stages: initiation (ribosome assembly on mRNA), elongation (addition of amino acids), and termination (stop codons). Prokaryotes utilize polycistronic mRNA to synthesize multiple proteins from a single transcript and perform coupled transcription and translation for efficient protein production.
- 8.3: Eukatroyotc Transcription
- This page details eukaryotic transcription, the process of converting DNA into RNA in the nucleus. It involves RNA polymerase and transcription factors that bind to promoters, initiating transcription. The stages include initiation, elongation, and termination. The primary RNA transcript undergoes processing, adding a 5' cap and poly-A tail, alongside intron splicing, to form mature mRNA, which then exits the nucleus for translation.
- 8.4: Eukaryotic Translation
- This page explains translation, the process of decoding mRNA to synthesize proteins in the cytoplasm using ribosomes, tRNA, and amino acids. It details the three stages: initiation (ribosome binding), elongation (sequential amino acid addition), and termination (at stop codons). Post-translation, proteins fold and may undergo modifications, with polysomes allowing for the production of multiple protein copies from one mRNA strand.