1.4 Carbohydrates

A h_______ reaction allows the release of single sugar molecules, m______, that the tissues can use for energy.

A hydrolysis reaction allows the release of single sugar molecules, monosaccharides, that the tissues can use for energy.

alpha-glucose

1-carbon OH is down

beta-glucose

1-carbon OH is up

Almost all digested carbohydrates reaching body cells have been converted to glucose by the l_____ or e_______ (i______ cells).

Almost all digested carbohydrates reaching body cells have been converted to glucose by the liver or enterocytes (intestinal cells).

cellulose structure

Beta 1,4 glycocidic linkages in a straight line.

Both glucose and fructose are _____ (#?)-carbon carbohydrates called _______.

Both glucose and fructose are six carbon carbohydrates called hexoses.

glycogen structure

Branches have alpha(1,6) bonds; Linkages have alpha(1,4) bonds.

Carbohydrates can be thought of as carbon and water in a fixed ____-to-_____ ratio. For each carbon atom there exists _____ oxygen atom and _____ hydrogen atoms. The formula for any carbohydrate is:

Carbohydrates can be thought of as carbon and water in a fixed one-to-one ratio. For each carbon atom there exists one oxygen atom and two hydrogen atoms. The formula for any carbohydrate is: Cn(H2O)n (n's are subscripts)

Carbohydrates do not store as much energy per gram as lipids simply because they do not have as high a concentration of ____-____ bonds; a______ are also present along the carbon chain.

Carbohydrates do not store as much energy per gram as lipids simply because they do not have as high a concentration of C-H bonds; alcohols are also present along the carbon chain.

Glycogen is a branched glucose polymer with _____-linkages. Glycogen is found in all animal cells, but especially large amounts are found in m____ and l____ cells.

Glycogen is a branched glucose polymer with alpha linkages. Glycogen is found in all animal cells, but especially large amounts are found in muscle and liver cells.

In the absence of insulin, only the b____ and the l____ continue to absorb glucose.

In the absence of insulin, only the brain and the liver continue to absorb glucose.

Insulin _______ the rate of facilitated diffusion for glucose and other monosaccharides.

Insulin increases the rate of facilitated diffusion for glucose and other monosaccharides.

Like most animals, humans have enzymes to digest the _____-linkages of s_____ and g_____ but do not have enzymes that can digest the _____-linkages of c______.

Like most animals, humans have enzymes to digest the alpha linkages of starch and glycogen but do not have enzymes that can digest the beta linkages of cellulose.

Only certain e______ cells in the d_____ t____ and the p_____ t_____ of the k_____ are capable of absorbing glucose against a concentration gradient. This is done via a s_____ a_____ t_____ mechanism down the concentration gradient of sodium. All other cells absorb glucose via f______ d______.

Only certain epithelial cells in the digestive tract and the proximal tubule of the kidney are capable of absorbing glucose against a concentration gradient. This is done via a secondary active transport mechanism down the concentration gradient of sodium. All other cells absorb glucose via facilitated diffusion.

Plants also use glucose molecules to form c_____. C_____ is used as a s______ material rather than for energy storage, and in contrast to starch and glycogen, it is composed of b____-linkages.

Plants also use glucose molecules to form cellulose. Cellulose is used as a structural material rather than for energy storage, and in contrast to starch and glycogen, it is composed of beta linkages.

Plants use s______ for long-term storage instead of glycogen. Starch comes in two forms: amy_____ and amy_____. Amy____ may be branched or unbranched and has the same alpha linkages as glycogen. Amy_____ resembles glycogen but has a different branching structure.

Plants use starch for long-term storage instead of glycogen. Starch comes in two forms: amylose and amylopectin. Amylose may be branched or unbranched and has the same alpha linkages as glycogen. Amylopectin resembles glycogen but has a different branching structure.

The cell can o_____ glucose to transfer its chemical energy to a more readily usable form, ___. If the cell already has sufficient ___, glucose is polymerized to the polysaccharide form, g_____, or converted to fat.

The cell can oxidize glucose to transfer its chemical energy to a more readily usable form, ATP. If the cell already has sufficient ATP, glucose is polymerized to the polysaccharide form, glycogen, or converted to fat.

The liver regulates the blood glucose level, so liver cells are one of the few cell types capable of ________ glucose from glycogen and ________ (destination?) when needed.

The liver regulates the blood glucose level, so liver cells are one of the few cell types capable of reforming glucose from glycogen and releasing it back into the bloodstream when needed.

The primary biological importance of carbohydrates lies with their usefulness in e____ s_____ and providing easily accessible e_____ to the body. As with fats, the high concentration of ___-___ bonds in carbohydrates allows for the storage of a large amount of ______.

The primary biological importance of carbohydrates lies with their usefulness in energy storage and providing easily accessible energy to the body. As with fats, the high concentration of C-H bonds in carbohydrates allows for the storage of a large amount of energy.

The structure of carbohydrates also makes it possible for them to join together through a d_______ reaction, forming long chains, called p______, for energy storage.

The structure of carbohydrates also makes it possible for them to join together through a dehydration reaction, forming long chains, called polysaccharides, for energy storage.