carbohydrates

"a-.."/a[#] is alpha, B or b-... / b/B[#]is beta; im too lazy to put in the real letter

empirical formula for carbohydrate

(CH₂O)_n, n = number of C atoms and ≥ 3

what are carbohydrates used for?

• cell-cell signaling when attached to cell membranes

• building blocks for larger molecules

• energy source

monosaccharide (carbohydrate)

• “simple sugars”

• exist as straight chain

  • also exist as ring structure when there are 5+ carbons and dissolved in water

  • ring structures are usually more conducive to chemical reactions/interactions

carbohydrates are either [__] or [__] depending on which carbonyl group they have

carbohydrates are either aldehydes or ketones depending on which carbonyl group they have

how can carbohydrates be classified?

• number of Carbon atoms & suffix “-ose”

• eg. Hexoses have 6 Carbons

which 3 monosaccharides are isomers of each other?

glucose, fructose, galactose → different chemical & physical properties

alpha-glucose (a-glucose)

isomer of glucose our body can use (hydroxyl group on carbon 1 sticks DOWN)

beta-glucose (B-glucose)

isomer of glucose our body doesn’t recognize

(hydroxyl group on carbon 1 sticks UP)

monosaccharides and diet (where it’s found (un)naturally, where you should consume carbs)

• found naturally in foods like fruit, milk, milk products

• occurs also in processed & refined sugars (candy, table sugar, syrup, soft drinks..)

• carbohydrate intake should come from complex carbohydrates (starches) & naturally occurring sugars (NOT processed&refined)

about oligosaccharides

• disaccharide, trisaccharide, or 2-10 monosaccharide units

• formed in an anabolic reaction (dehydration synthesis)

3 common oligosaccharides & their composition

• maltose — 2 a-glucose together (found in beer)

• lactose — galactosr and 1 b-glucose (sugar found in milk) → 1 glucose and galactose

• sucrose — 1 a-glucose and 1 fructose (found in table sugar)

what is a glycosidic linkage (we never defined this in notes)

a chemical bond in the form of a covalent connection that connects a carbohydrate (sugar) molecule to another group, which might be another carbohydrate or not

glycosidic linkage bond between sugars in Maltose

a (alpha) 1-4 glycosidic linkage → occurs between Carbon 1 of the first a-glucose and Carbon 4 of the second a-glucose

glycosidic linkage bond between sugars in Lactose

B 1-4 glycosidic linkage (between Carbon 1 of the glucose and carbon 4 of the galactose)

glycosidic linkage bond between sugars in Sucrose

a 1-2 glycosidic linkage (between carbon 1 of the glucose and carbon 2 of the fructose)

polysaccharides (what is it, structure)

• hundreds-thousands of monosaccharides held together by glycosidic linkages

• some straight chained, some are branched, others have side groups attached

use of polysaccharides

primarily used as carbohydrate storage, long-term energy source, some also used for structural support of the cell/organism

what is starch used for in plants?

primary carbohydrate storage unit of plants

the 2 polysaccharides that starch is composed of

• amylose: a straight chain of a-glucose molecules in an a1-4 glycosidic linkages

• amylopectin: main chain of a-glucose in a1-4 linkages & branches of a-glucose off the main chain in a1-6 linkages at the branch points

why is starch insoluble & where is it stored

insoluble because of the angles of the glycosidic linkages, stored mainly in chloroplasts & some fruit of plants

what is glycogen

long-term storage molecule in animals (similar to amylopectin but with more branching)

where does unused glucose go in the body?

glucose not use as energy gets stored in the liver & muscles as glycogen

where is cellulose found & what it’s used for

in plant cell walls, used for structural support

structure of cellulose

• straight chain of B-glucose held together by B1-4 glycosidic linkages

• every second glucose molecule is inverted

why do cellulose chains pack close together

H-bonds (which are strong) form between adjacent cellulose strands

cellulose in diet and digestion

• cannot digest it due to enzymes being unable to hydrolyze B1-4 glycosidic linkages (upside down glucose molecules)

• important part of the diet because it cleans out digestive tract (fiber)

chitin

• material that makes of the exoskeletons of a lot of arthropods

• its monomers are glucose w/ nitrogen group attached to the 2nd carbon

• we can’t break it down because of B-glucose (B1-4 glycosidic linkage)

where is chitin used

contact lenses & biodegradable stitches

complex polysaccharides foods provide…

vitamins, minerals, fiber