Carbohydrates Flashcards
What are examples of carbohydrates?
Grass, corn silage, hay, corn, potato, sugar beets,
What roles do carbohydrates play in plants?
1) Structural Support
- cellulose
2) Energy Reserve
- starch
3) Tissue Synthesis
- DNA and RNA framework
Where are there large amounts of carbohydrates?
Plant tissue
-starch, fiber (cellulose, hemicellulose)
Where are there small amounts of carbohydrates?
Animal tissue
-glucose: “blood sugar” and glycogen (energy storage)
What are simple carbohydrates?
Monosaccarhides and Disaccarhides
What do monosaccharides consist of?
glucose, fructose, and galactose
What do disaccharides consist of?
lactose, fructose, and maltose
How many sugar units do monosaccharides have?
1
How many sugar units to disaccharides have?
2
What does lactose consist of?
glucose and galactose
What does sucrose consist of?
glucose and fructose
What does maltose consist of?
glucose and glucose
What are complex carbohydrates?
oligosaccharides and polysaccharides
How many sugar units do oligosaccharides have?
3-10
How many sugar units do polysaccharides have?
more than 10
What do oligosaccharides consist of?
raffinose, stachyose, verbascose
What do polysaccharides consist of?
starch, glycogen, dietary fiber
What do monosaccharides consist of?
single sugar units of C:H:O in the ratio of 1:2:1
How are monosaccharides characterized?
the number of C atoms they contain
there are about 70 known monosaccharides
What are isomers?
each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
What is glucose?
- commercially produced by hydrolysis of cornstarch
- most abundant monosaccharide in the body
What is galactose?
- combines glucose to form lactose
- component of galactolipids found in plants
*galactolipids: lipids bound to galactose
What make cell membranes?
phospholipids
What are the cerebrosides?
lipids that form shape around your nerves.
What is fructose?
- sweetest of all sugars
- combines with glucose to form sucrose
- major sweetener used in many foods
What is ATP?
Adenosine Triphosphate- energy currency of cells
ribose+adenine=
adenosine
What is the difference between ATP and ADP?
number of phosphates
What are disaccharides?
consist of 2 monosaccharide units attached together by a glycosidic bond
What is a reaction with water?
hydration reaction or condensation reaction
What is lactose?
- only found naturally in milk
- glucose+galactose
- Beta-1,4 glycosidic bond
- broken down by lactase
What is sucrose?
- table sugar
- most widely distributed disaccharide
- glucose+fructose
- alpha-1,2 glycosidic bond
- broken down by sucrase
What is maltose?
- contained in malt beverages
- hydrolysis of starch
- glucose+glucose
- alpha-1,4 glycosidic bond
- broken down by maltase
What are oligosaccharides?
- components of cell membranes
- sources: dried beans, soybeans, peas, lentils, sweet potato
- part of milk (human milk)- prebiotic effects
Do humans lack enzymes to digest oligosaccharides?
Yes. They cause bloat, cramps, and gas.
What are polysaccharides?
made of hundreds of monosaccharide units bonded together to form high molecular weight polymers
How is starch stored in a polysaccharide?
- in the form of amyloplasts
- amylose and amylopectin
Where is glycogen stored in a polysaccharide?
liver and muscles
also, kidneys and uterus
What is fiber key for?
ruminants
not used for energy storage in humans
What is starch?
long chains of glucose molecules connected together
What are the two forms of starch?
1) Amylose
- alpha-1,4 (unbranched chains)
2) Amylopectin
- alpha- 1,4 and alpha 1,6 (branched chains)
What is amylose?
-long unbranched chains of glucose connected by alpha-1,4 linkage
-soluble in water
20-30% of starch in most plants
What is amylopectin?
- branched chain polymer with alpha-1,4 and alpha-1,6 linkages
- each side chain contains 19-26 glucose units
- comprises 70-80% of starch
What is glycogen?
- branched chain polymer
- alpha-1,4 and alpha-1,6 linkages
- storage form of glucose in animals
What is carbohydrate loading?
the dietary technique used by athletes to increase glycogen stored in the liver and muscle tissue
- delays the onset of fatigue
- avoid early low energy levels
What are soluble fibers?
some hemicellulose, pectin, gums, beta-glucans
What are insoluble fibers?
lignin, cellulose, some hemicellulose
What is fiber?
structural carbohydrates in plants
-stem, husk of seeds
What is cellulose?
- long linear chains of glucose units in beta-1,4 linkage
- insoluble in water
- indigestible by mammalian enzymes
What is hemicellulose?
chain of different sugars in backbone, side chains
beta- 1,4 and alpha-1,2 linkages
What is lignin?
- highly branched poly-phenolic polymer
- many phenol units with strong bonding
- 2nd most abundant organic polymer
- does NOT contain sugar units (so not a carbohydrate)
- forms linkages with cellulose and hemicellulose
- content increases as plants mature
- indigestible by mammalian, microbial cells
What is pectin?
- complex group of pectic polysaccharides rich in galacturonic acid
- alpha-1,4 linked galacturonic acid
- some have sugar side chains
- found in cell wall of citrus fruits (gelling agent in jam and jellies)
What are Beta-Glucans?
homo-polymers of glucopyranose units with beta-1,4 and beta-1,3 linkages
- water soluble
- highly fermentable
- used commercially as functional fiber
- reduce cholesterol
- reduce post prandial glucose concentration
