Chapter 15 Carbohydrates

How is D-fructose different from both d-glucose and d- galactose?

It is a ketohexose.

how is haworth structure of galactose different to glucose?

OH group on carbon 4 is drawn above in galactose, whereas its drawn below in glucose. other than that everything is the same

what are the most important polysaccharides?

Starch,(amylose, amylopectin) cellulose, and glycogen.

What is respiration?

The process of transferring energy from oxidized glucose, which provides energy for our cells.

What are the kind and number of atoms in the ring portion of the Haworth structure of glucose?

There are 6 ring atoms (forms hexagon shape) , 5 of which are carbon and the 6th is an oxygen, single bonded to carbon 1 which was orginally a carbonyl group. The 6th carbon atom is attached to carbon 5 as a group.

15.37 Describe the similarities and differences in the following: a. amylose and amylopectin b. amylopectin and glycogen

a. amylose is non branched while amylopectin is branched, with a a(1-6) glycosidic bond occurring every 25 glucose molecules. b. both are branched, however glycogen is higher branched, with the a(1-6) bond occurring ever 10-15 glucose molecules. amylopectin occurs every 25 glucose.

15.39 Give the name of one or more polysaccharides that matches each of the following descriptions: a. not digestible by humans b. the storage form of carbohydrates in plants c. contains only a(1-4)-glycosidic bonds d. the most highly branched polysaccharide

a. cellulose b. starch(amylose, amylopectin) c. amylose d. glycogen

15.20 Identify a monosaccharide that fits each of the following descriptions: a. found in high blood levels in diabetes b. is also called fruit sugar

a. d- glucose b. d-fructose

15.19 identify the monosaccharide that fits each of the following descriptions: a. is also called blood sugar b. is not metabolized in a condition known as galactosemia

a. d-glucose b. d-galactose

Identify the polysaccharide described by each of the following: a. a polysaccharide that is stored in the liver and muscle tissues b. an unbranched polysaccharide containing b(1-4)-glycosidic bonds c. a starch containing a(1-4)- and a(1-6)-glycosidic bonds

a. glycogen b. cellulose c. amylopectin and glycogen

15.35 Identify the disaccharide that fits each of the following descriptions: a. ordinary table sugar b. found in milk and milk products c. also called malt sugar d. hydrolysis gives galactose and glucose

a. sucrose b. lactose c. maltose d. lactose

15.36 Identify the disaccharide that fits each of the following descriptions: a. not a reducing sugar b. composed of two glucose units c. also called milk sugar d. hydrolysis gives glucose and fructose

a. sucrose b. maltose c. lactose d. sucrose

what are the dangers of galactosemia?

accumulation of d-galactose in blood and tissues can lead to cataracts, mental retardation, failure to thrive and liver disease.

sugar alcohols are also called?

alditols.

What types of chemical reactions do monosaccharides undergo?

aldose and ketose undergo oxidation. the aldehyde of monosaccharides forms carboxylic acid. ketones normally don't oxidize, however here they do, rearranging into aldehydes, which can then oxidize.

what is the difference between an aldose and a ketose?

aldose contains aldehyde on first carbon of carb, ketose contains ketone on second carbon of carb.

Which carbohydrates are digestible,which are not and why?

all carbs are digestible except for cellulose. our bodies have an enzyme amylase, found in saliva and pancreatic juices, which can hydrolyze the a(1-4) glycosidic bonds of starches but not b(1-4) bonds. For this reason, cellulose is not digestible in humans.

describe amylose in starch.

amylose makes up 20% of starch, consisting of 250-4000 a-d-glucose molecules connected by a(1-4) glycosidic bonds in a continuous unbranched chain, coiled in helical fashion.

What is glycogen?

animal starch, polymer of glucose stored in liver and muscle of animals.

what is the difference in fischer projections of d-glucose and d-galactose?

arrangement of OH group on carbon 4.

Which reagent is used to oxidize monosaccharides?

benedicts reagent

Which anomer predominates in aqueous solution of glucose?

beta anomer accounts for 64%, alpha anomer accounts for 36%

What is the most abundant organic compound?

carbohydrates

what is the catalyst for formation of disaccharides?

catalyst is named after disaccharide produced followed by synthase. ex, maltose synthase, lactose synthase.

what is cataracts?

clouding of the lens of the eyes, producing cloudy vision.

What is a polysaccharide?

consist of 3 or more monosaccharides joined together.

why are carbs called polyhydroxy aldehyde or polyhydroxy ketone.

contain multiple hydroxyl groups.

How does the haworth structure of a disaccharide differ from monosaccharides?

contains a glycosidic bond, which is a hemiacetal bond that connect two monosaccharides together to form disaccharide.

15.7 What are the functional groups and number of carbons in a ketopentose?

contains hydroxyl, a ketone, and 5 carbons

what happens to excess glucose in the body?

converted to glycogen and stored in liver and muscles. Excess glucose that cannot be stored in liver or muscles is converted and stored as fat in unlimited amounts.

which is the most common hexose?

d-glucose

what is another name for glucose?

dextrose or blood sugar

how does sucrose differ from maltose and lactose in terms?

does not exist in open chain form, thus oxidation not possible and it is not a reducing sugar like maltose and lactose are.

How is high fructose corn syrup made?

enzyme breaks down disaccharide sucrose into d-fructose and d-glucose.

how are starches digested and degraded in our bodies, list the saccharides produced from start to end.

enzymes such as amylase in saliva and maltose in intestines aid digestion of starches. amylose or amylopectin is digested by amylase into smaller saccharides, dextrins. amylase further digest dextrins into maltose, where maltase digest it into many smaller d-glucose units. Hydrolysis produces same results.

Where is d-galactose found and what is its importance in the diet?

found in milk. important for brain membranes and nervous system.

What happens to fructose when in benedict's solutions?

fructose, a reducing sugar, rearranges ketone to form aldehyde, which can then oxidize.

What is galactosemia?

genetic disease where there is a deficiency in converting galactose to glucose due to missing enzyme.

What are the reactants and products of respiration?

glucose and oxygen are the reactants of respiration. CO2 and H2O and energy are the products formed when glucose is metabolized in the body.

what are the most common monosaccharides and how are they all similar?

glucose, fructose, galactose, they are all structural isomers of C6H12O6

What is the function of glycogen and how is it hydrolyzed in the body?

glycogen is hydrolyzed in our cells at a rate that maintains blood glucose levels and thus provides energy to our cells in between meals.

Describe the glycosidic bond of maltose and how it is formed.

glycosidic bond forms between carbon 1 and 4 of two a-d-glucose molecules alongside a loss of water. the glycosidic bond is designated as a(1-->4) to show that alpha anomer of carbon 1 is bonded to carbon 4 of second glucose.

15.5 What functional groups are found in all monosaccharides?

hydroxyl groups are found in all carbs, alongside a carbonyl group located either on the 1st or 2nd carbon, depending if its an aldehyde(aldose) or ketone(ketose) group.

What are some abnormalities in relation to blood glucose levels?

hyper and hypo glycemia are characterized by excess or sublevel glucose levels in blood, both of which have serious consequences. Diabetes can cause hyperglycemia, which is due to lack of insulin production, thus the uptake of glucose by cells is impaired. hypoglycemia can be caused by over production of insulin.

what is the significance of d-glucose to disaccharides and polysaccharides?

it is the building block to most, including sucrose, lactose, and maltose (disaccharides). also to amylose, cellulose and glycogen (polysaccharides).

what is the importance of d-fructose?

it is twice as sweet as sucrose(table sugar). it is thus used as a sweetner in things such as soft drinks.

How is the glycosidic bond in lactose different from maltose?

lactose is composed of b-d-galactose and a-d-glucose, whereas maltose is comprised of two a-d-glucose molecules. also differs in the fact that the glycosidic bond of lactose is b(1-4) because OH group of carbon 1 of galactose forms glycosidic bond with carbon 4 of glucose. OH group on cabron 1 of glucose still free however, thus it can be a or b anomers. When in open chain, provides aldehyde that can be oxidized.

what is lactose and where is it found in nature?

lactose is milk sugar, a disaccharide found in milk products.

Describe amylopectin structure in starch.

makes up 80% of starch. glucose molecules also has a(1-4) glycosidic bond. every 25 units has a a(1-6) glycosidic bond that occurs between carbon 1 of branch and carbon 6 of main chain.

what are the most common disaccharides and what are their compostition?

maltose composed of 2 a-d-glucose subunits. lactose composed of a-d-glucose and b-d-galactose sucrose composed of a-d-glucose and b-d-fructose

What type of carb is glucose?

monosaccharide

What are the different types of carbohydrates?

monosaccharides, the simplest form which cannot be further hydrolyzed disaccharides, consist of two monosaccharide units joined together. hydrolysis can separate into two separate monosaccharide units polysaccharides, consist of many monosaccharide units and is thus called a polymer. can hydrolyze and yield many monosaccharide units.

Where is maltose derived from in nature?

obtained from starch, found in germinating grains

How are monosaccharides oxidized?

only open chain form is capable. aldehyde then oxidizes to carboxylic acid, now a sugar acid.

How are carbohydrates formed?

photosynthesis, in which the suns energy combines the carbon atoms from CO2 and hydrogen from H2O into glucose, C6H12O6

what is cellulose?

polysaccharide that makes up plant cell walls and important structural component of wood and cotton.

Mutarotation

process of rings of d-glucose opening and closing, with ability to change anomers.

What are the reactants and products of reduction of monosaccharides?

reactants are the monosaccharide and H2, reacting with Pt. as catalyst, to form sugar alcohol. Aldehyde reduces to alcohol basically.

what are the reactants and products of the reduction reaction of monosaccharides?

reactants are the monosaccharide plus 2 Hydrogen atoms, catalyzed by Pt, producing a sugar alcohol(alditol).

what happens to benedict's reagent when oxidation of monosaccharide occurs?

reduced from blue (2Cu+) to brick red (Cu+)

What is a carbohydrate that reduces another substance called?

reducing sugar.

what other molecule is produced alongside the formation reaction of a disaccharide?

remember formation of disaccharide stems from dehydration reaction of 2 monosaccharides, thus the disaccharide is produced alongside H2O.

How are sugar alcohols named?

replace -ose ending with -itol example: glucose, glucitol

How are sugar acids named?

replace -ose ending with -onic acid.

What is the downside of sugar alcohols used in sugar free foods and diet foods?

some experience side effects such as gas, diarrhea, diabetics can develop cataracts due to accumulation of d-sorbitol in lens of eye.

what is starch composed of and where is it found throughout nature?

starch is composed of amylose 20% and amylopectin 80%. it is storage form of glucose in plants. found as insoluble granules in rice, beans, potatoes and cereals.

Compare and contrast glycogen to amylopectin.

structure is very similar, identical except that it is more highly branched, instead having the a(1-6) glycosidic bond occur after every 10-15 glucose molecules

Describe the glycosidic bond of sucrose.

sucrose consist of b-d-fructose and a-d-glucose . the glycosidic bond is a,b,(1-2). here the 1 carbon of glucose bonds with 2 carbon of fructose.

What is produced as a result of the reduction of carbonyl group of monosaccharides?

sugar alcohols.

how are anomers determined?

the OH group of carbon 1 determines this. if OH group is on top, it is beta anomer, if on bottom, alpha anomer.

How is the anomer of a maltose determined?

the OH group on the carbon of second glucose is free, thus it is an open chain that can form alpha or beta anomers.

Why is D-glucose called a reducing sugar?

the aldehyde of glucose oxidizes in benedict's solutions to form carboxylic acid, which reduces Cu2+ to Cu+, thus it being called a reducing sugar.

what is the combination of glucose and respiration called?

the carbon cycle. energy from sun stored in plants during photosynthesis is used when those carbs are metabolized in our bodies for energy.

What reaction forms disaccharides?

the dehydration reaction of 2 monosaccharides joins them together. The hydroxyl group of carbon 1 of one monosaccharide reacts with hydroxyl group of another monosaccharide.

what happens in people who lack the enzyme for digestion of lactose?

the enzyme that digest lactose is lactase. when this enzyme is missing, lactose isn't digested and enters the colon. bacteria in colon then digest the lactose via fermentation, which produces CO2 and methane as by products, causing bloating and cramps.

what are the reactants and products of hydrolysis of carbohydrates?

the specific type of carb, and H2O hydrolyzed in presence of H+ or enzyme to form monosaccharide units

A solution containing a tablet of Benedict's reagent turns brick red with a urine sample. What might this result indicate?

the urine might contain excess glucose, a reducing sugar, which oxidizes in presence of benedict's solution, turning it from blue to brick red color, which occurs as a result of it being reduced. Thus the person may have type 2 diabetes.

What are the kind and number of atoms in the ring portion of the Haworth structure of fructose?

there are 5 ring atoms (forms pentagon shape), 4 are carbon, 1 is oxygen. Carbons 1 and 6 are represented as substituents of carbon 2 and 5 respectively.

15.8 What are the functional groups and number of carbons in an aldohexose?

there are 6 carbons, an aldehyde group and hydroxyl group.

What ways are the most important polysaccharides previously listed are similar and different?

they all consist of d-glucose. they differ in the fact that they all have different types of glycosidic bond and amount of branching.

What are Haworth structures?

they are the ring structure of monosaccharides. cyclic hemiacetals produced from reaction of carbonyl group and hydroxyl group. most stable form of pentose and hexose

How are fischer projections converted to haworth structures?

turn fischer projection 90 degrees clockwise. fold chain into hexagon. rotate groups on carbon 5 and bond O on carbon 5 to carbon 1. With carbons 2 and 3 as base, move remaining carbons upward. Rotate groups on carbon 5 so that OH group is clser to carbon 1.

What is the composition of a disaccharide?

two monosaccharides linked

what are some everyday uses of sucrose?

used as table sugar, derived from sugar cane or sguar beets. we used as sweetener.

what are sugar alcohols used for?

used for as sweeteners in sugar free foods.

What are some uses of maltose?

used in candies, cereal, and brewing of beverages. Also when hydrolyzed by a yeast enzyme, glucose is obtained which can be used for fermentation of ethanol.

In what instance would maltose be a reducing sugar?

when it is an open chain, it provides aldehyde that an be oxidized.

describe the structure of cellulose.

~ Long, unbranched chains of β-glucose ~ Glyosidic bonds makes a straight chained molecule, not helical like amylose ~ Cellulose chains are linked together by hydrogen bonds, keeping it aligned in parallel rows which also makes it insoluble in water.

How many carbons make up a monosaccharide?

3 to 7.

What are normal blood glucose levels?

70-90mg/dL

How are monosaccharides classified?

By the number of Carbons contained. 3 carbons triose 4 carbons tetrose 5 carbons pentose 6 carbons hexose 7 carbons heptose

what is the structure of carbohydrates?

Carbohydrates are made of carbon, hydrogen and oxygen,

Cellulose and amylose are both unbranched glucose polymers. How do they differ?

Cellulose has b(1-4) glycosidic bond whereas amylose has a(1-4) glycosidic bond.

What are some differences in the Fischer projections of D-glucose and D-fructose?

D-glucose is an aldose, D-fructose is a ketose.

how is galactosemia treated?

Elimination of galactose and lactose from diet

what is the catalyst for hydrolysis of carbohydrates?

H+ acid or enzyme.