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Flashcards in Nutrition Deck (140)
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91

The four main types of atoms found in nutrients:

Hydrogen (H)
Oxygen (0)
Nitrogen (N)
Carbon (C)

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Each atoms can form a certain number of chemical bonds with other atoms:

Hydrogen: 1
Oxygen: 2
Nitrogen: 3
Carbon: 4

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Monosaccharides

Single sugars. Carbohydrates of the general formula CnH2n0n that typically form a single ring.

One of the sugars, sometimes called simple carbohydrates (along with disaccharides).

All three monosaccharides have the same formula, but their structures differ.

mono = one
saccharide = sugar

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Disaccharides

Sugars composed of pairs of monosaccharides, each containing a glucose paired with one of the three other monosaccharides.

One of the sugars, sometimes called simple carbohydrates (along with monosaccharides).

di = two

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Polysaccharides

Large molecules composed of chains of monosaccharides.

Starches and fibers, sometimes called complex carbohydrates.

An intermediate string of 3-10 monosaccharides is an oligosaccharide.

poly = many
oligo = few

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The 6 most important sugars in nutrition:

Monosaccharides:
Glucose
Fructose
Galactose

Disaccharides:
Maltose (glucose + glucose)
Sucrose (glucose + fructose)
Lactose (glucose + galactose)

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Glucose

A monosaccharide, sometimes known as blood sugar or dextrose.

ose = carbohydrate
Blue hexagon

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Fructose

A monosaccharide, sometimes known as fruit sugar or levulose. The sweetest of the sugars. Found abundantly in fruit, honey, and saps. Same formula as glucose with a different structure.

fruct = fruit
Purple hexagon

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Galactose

A monosaccharide, part of the disaccharide lactose. Occurs naturally as a single sugar in only a few foods.

Green hexagon

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Carbs and all other energy nutrients are taken apart and put back together by:

Condensation and hydrolysis.

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Condensation

A chemical reaction in which water is released as two reactants combine to form one larger product. Makes a disaccharide by linking two monosaccharides together.

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Maltose

A disaccharide composed of two glucose units; sometimes known as malt sugar. Produced whenever starch breaks down, as in carb digestion and in fermentation.

Two blue hexagons

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Sucrose

A disaccharide composed of glucose and fructose; commonly known as table sugar, beet sugar, or cane sugar. Also occurs in many fruits and some vegetables and grains.

sucro = sugar
A blue hexagon and a purple hexagon

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Lactose

A disaccharide composed of glucose and galactose; commonly known as milk sugar.

lact = milk
A blue hexagon and a green hexagon

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The three types of polysaccharides important in nutrition:

Glycogen
Starches
Fibers

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Glycogen

An animal polysaccharide composed of glucose; manufactured and stored in the liver and muscles as a storage form of glucose. Not a significant food source of carbs and is not counted as a dietary carb in foods.

glyco = glucose
gen = give rise to

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Starches

Plant polysaccharides composed of glucose. The human body stores glucose as glycogen, but plants store glucose as starches. Grains are the richest food source of starch.

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Fibers (dietary fibers)

In plant foods, the nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digested by GI tract bacteria. Includes cellulose, hemicelluloses, pectins, gums, and mucilages as well as the nonpolysaccharides lignins, cutins, and tannins. Occur naturally in plants.

Soluble fibers and insoluble fibers.

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Soluble fibers

Nonstarch polysaccharides that dissolve in water to form a gel (viscous), like pectin. They are also fermentable.

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Viscous

A gel-like consistency.

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Fermentable

The extent to which bacteria in the GI tract can break down fibers to fragments that the body can use.

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Insoluble fibers

Nonstarch polysaccharides that do not dissolve in water, do not form gels, and are less readily fermented.

Promote bowel movements, alleviate constipation, and prevent diverticular disease.

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Resistant starches

Starches that escape digestion and absorption in the small intestine of healthy people. Classified as dietary fibers. May support a healthy colon.

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Phytic acid

A nonnutrient component of plant seeds; also called phytate. Occurs in the husks of grains, legumes, and seeds, and is capable of binding minerals such as zinc, iron, calcium, magnesium, and copper in insoluble complexes in the intestines, which the body excretes unused.

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Amylase

A salivary enzyme that hydrolyzes amylose (a form of starch). Amylase is a form of carbohydrase.

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Maltase

An enzyme that hydrolyzes maltose

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Surcrase

An enzyme that hydrolyzes sucrose

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Lactase

An enzyme that hydrolyzes lactose

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Carbohydrase

An enzyme that hydrolyzes carbohydrates

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Available carbohydrates

Starches and sugars - because the body can break them down and use them