5: Proteins
- Page ID
- 156291
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Proteins are essential macronutrients that play a critical role in nearly every biological process in the human body. Composed of amino acids, proteins are required for the growth, maintenance, and repair of body tissues, including muscles, organs, skin, and hair. Beyond their structural functions, proteins also serve as enzymes, hormones, and immune system components, making them vital for metabolism and overall health.
- 5.1: Protein Structure
- This page explains that proteins are complex molecules composed of amino acids connected by peptide bonds and contain nitrogen. There are 20 common amino acids, each with a distinct side chain. Protein structure has four levels: primary, secondary, tertiary, and quaternary, each representing different aspects of protein configuration. The specific shape of a protein is essential for its function, and alterations in structure can greatly influence its biological activity.
- 5.2: Amino Acid Classification
- This page classifies amino acids into three categories: essential (must be obtained through diet), nonessential (can be synthesized by the body), and conditionally essential (generally nonessential but essential under certain conditions such as stress or illness). Examples of essential amino acids include leucine and lysine; nonessential examples are alanine and aspartic acid; and conditionally essential examples include arginine and glutamine.
- 5.3: Food Proteins
- This page examines protein sources, emphasizing that animal products offer superior protein quality compared to plant-based foods, though legumes are notable for their higher protein content. It discusses amino acid classifications and the necessity of protein complementation for vegetarians and vegans. Additionally, the text explores genetic modification to improve protein quality in staple crops to combat global malnutrition while addressing potential risks related to GM crops.
- 5.4: Why We Need Protein
- This page discusses the importance of proteins for bodily functions, emphasizing their roles in support, metabolism, immunity, transport, and hormones. It outlines the recommended daily allowance (RDA) of 0.8 g/kg of body weight, with increased needs for certain groups. The page warns about the potential health risks of excessive protein intake and deficiency, notably highlighting Protein-Energy Malnutrition (PEM) with its forms, marasmus and kwashiorkor.
- 5.5: Chapter 5 References
- This page discusses the significance of proteins in biology and nutrition, outlining dietary guidelines and healthy protein sources. It includes insights from U.S. health and agriculture departments on nutritional recommendations and high-protein food sources, while linking protein intake to exercise. Additionally, it references data on malnutrition-related deaths, underscoring the critical need for sufficient protein consumption for maintaining overall health.