16: Carbohydrates
- Page ID
- 15935
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Glucose is one of the carbohydrates you will learn about in this chapter as we begin the study of biochemistry—the chemistry of molecules found in living organisms. Later we will study the other three major types of macromolecules found in living organisms: lipids, proteins, and nucleic acids.
- 16.0: Prelude to Carbohydrates
- This page discusses diabetes in the U.S., affecting approximately 17.9 million people, with 5.7 million undiagnosed cases. In 2006, it was the seventh leading cause of death, contributing to over 200,000 fatalities. The condition disrupts glucose metabolism, causing symptoms such as excessive hunger and thirst. It emphasizes the importance of the oral glucose tolerance test for diagnosis and the necessity for regular glucose monitoring for those diagnosed.
- 16.1: Carbohydrates
- This page discusses carbohydrates, biological molecules made of carbon, hydrogen, and oxygen, which are classified as monosaccharides, disaccharides, and polysaccharides. Plants synthesize carbohydrates like glucose through photosynthesis, providing essential nutrients for animals and humans, who depend on plants for these vital compounds needed for nucleic acids, proteins, and lipids.
- 16.2: Classes of Monosaccharides
- This page discusses the classification of monosaccharides by carbon content and carbonyl groups, highlighting the presence of chiral carbons that create stereoisomers, including enantiomers. It mentions the Fischer projection as a common representation and explains how optically active substances can rotate plane-polarized light, distinguishing them as dextrorotatory or levorotatory. This classification system is essential for studying the structural properties of sugars.
- 16.3: Important Hexoses
- This page discusses three important hexoses: D-glucose, D-galactose, and D-fructose, emphasizing their roles in energy, brain function, and sweetness. It highlights glucose as the most common sugar, galactose's origin from lactose, and fructose's presence in fruits and honey. Additionally, it contrasts artificial sweeteners (saccharin, aspartame, sucralose) regarding their history, sweetness, and safety.
- 16.4: Cyclic Structures of Monosaccharides
- This page explains that monosaccharides with five or more carbons can create stable cyclic structures in water, resulting in two anomers, alpha (α) and beta (β), which differ at the anomeric carbon. These forms exist in dynamic equilibrium with a straight-chain structure, a process known as mutarotation. While cyclic forms are predominant, a minor amount is present as an open-chain aldehyde that can engage in reactions.
- 16.5: Properties of Monosaccharides
- This page discusses monosaccharides such as glucose and fructose, highlighting their crystalline structure, high solubility in water, and the influence of functional groups on their chemical behavior. It describes how their aldehyde groups can be oxidized, which can be tested with mild oxidizing agents like Tollens’ and Benedict’s reagents. These tests are used to detect reducing sugars, such as glucose, in blood or urine, indicated by observable color changes.
- 16.6: Disaccharides
- This page discusses the enzyme sucrase's role in hydrolyzing sucrose into glucose and fructose, forming invert sugar that enhances food sweetness and remains dissolved. It highlights disaccharides like maltose and lactose, which provide energy and have distinct structures. It also addresses health concerns linked to high sucrose intake in American diets, contributing to obesity and dental issues, and notes the conditions affecting sugar digestion, such as lactose intolerance and galactosemia.
- 16.7: Polysaccharides
- This page discusses three key polysaccharides: glycogen, cellulose, and starch. Glycogen serves as the energy reserve in animals, primarily stored in the liver and muscles, with a highly branched structure. Cellulose, a structural component in plants, consists of linear glucose units linked by β-1,4-glycosidic bonds, making it indigestible to humans but digestible by some microorganisms.
- 16.S: Carbohydrates (Summary)
- This page discusses carbohydrates, including their structure as biological compounds of carbon, hydrogen, and oxygen. It covers types like monosaccharides, disaccharides, and polysaccharides (starch, glycogen, cellulose), and key concepts such as stereoisomerism and cyclic sugar structures. Reducing sugars are identified, with maltose and lactose being examples, while sucrose is noted for lacking a free anomeric carbon.