Chapter 5: Carbohydrates
How much energy is stored in carbohydrates?
4 kcal/gram
What is a trademark of a sugar?
A carbonyl group (>C=O)and multiple hydroxyl groups (-OH).
What is sucrose?
A disaccharide: glucose (C1) + fructose (C2). It is the most prevalent disaccharide. A.k.a. table sugar.
What is lactose?
A disaccharide: glucose (C1) + galactose (C4). The sugar present in milk.
What is maltose?
A disaccharide: glucose (C1) + glucose (C4). It is used in brewing beer.
What is amylose?
A plant polysaccharide which are made of a string of glucose molecules with 1,4 glycosidic bonds. This polymer is helical and unbranched.
Glucose monomers are linked together by what linkages?
Carbon 1 linked to carbon 4. This configuration makes starch polymers helical.
What polysaccharide is the most abundant organic substance on earth?
Cellulose.
What are examples of a structural polysaccharides?
Cellulose. Chitin.
What is this?
Count Carbons.
What would happen if a cow were given antibiotics that killed all the prokaryotes in its stomach?
The cow would not be able to digest cellulose as effectively, if at all. This would result in weight loss and/or death.
Can humans digest cellulose?
No. Humans lack the enzymes to digest cellulose. Foods that contain cellulose such as corn and spinach pass through the digestive tract as fiber. Although cellulose is not a nutrient for humans, it is an important part of a healthy diet.
Cellulose is found in what?
Paper and cotton.
Cellulose is a _________ (mono -, di- or polysaccharide)?
Poly
Glycogen is a _________ (mono -, di- or polysaccharide)?
Poly
Starch is a __________ (mono -, di- or polysaccharide)?
Poly
What are some examples of plant starches that humans eat?
Potatoes, wheat, corn, rice.
Name two Pentoses (C5 H10 O5).
Ribose, Ribulose.
Why is cellulose so strong?
Since the three-dimensional shape of celluloses straight, this allows hydrogen bonding with hydroxyl group of other cellulose molecules, resulting in crosslinks between strands. parallel cellulose molecules form units called microfibrils. A cellulose molecule is unbranched.
What is a monosaccharides' general molecular formula?
Some multiple of CH2O.
How is starch and cellulose different?
Starch has 1-4 linkage of ALPHA glucose monomers. All monomers are in the same orientation. The three-dimensional shape is helical. Cellulose has 1-4 linkage of BETA glucose monomers. Every other beta glucose monomer is upside down with respect to its neighbor. The three-dimensional shape is straight.
Plants store polysaccharides as what?
Starch. These are found as granules within the cellular structures known as plastids.
What is chitin?
Structural polysaccharide found in the exoskeletons of insects and fungi cell walls.
What is a carbohydrate?
Sugars and polymers of sugars.
Is fructose an aldose or a ketose?
ketose
Examples of polysaccharides
starch, glycogen, cellulose, chitin
Examples of disaccharides
sucrose, lactose, maltose
What is the formula for a monosaccharide that has three carbons?
C3 H6 O3
What is the formula of a monosaccharide that has five carbons?
C5 H10 O5
What is the formula of a monosaccharide that has six carbons?
C6 H12 O6
What is the chemical formula for maltose, if maltose is a disaccharide of two glucose monomers?
C12 H22 O11
Draw a amylose polymer.
1-4 Linkage of Alpha monomers
Draw a cellulose polymer.
1-4 linkage of Beta monomers.
What are three major ways to classify a sugar?
1. Location of the carbonyl group (aldose vs ketone). 2. Size of the carbon skeleton (trioses-3, pentoses-5, hexoses-6) 3. Spatial arrangement of their parts around asymmetric carbons (which side the -OH is located).
What is amylopectin?
A plant polysaccharide which are made of a string of glucose molecules with 1,4 glycosidic bonds. This polymer is helical. However, this starch has branch points with a 1-6 linkage at the branch points.
What is cellulose?
A structural polysaccharide (made of Glucose polymers) that is common in the cell walls of many organisms.
An aldose sugar is also known as what?
Aldehyde sugar
What are glucose and galactose? 1. Aldoses 2. Ketoses
Aldoses
Simple sugars are 1. major fuel for cellular work 2. serve as raw materials for amino acids 3. serve as raw materials for fatty acids 4. all of the above
All of the above
Polysaccharides 1. service as storage material and release sugars as needed by the cells by process of hydrolysis. 2. building material for structures that protect the cell or the whole organism 3. all of the above. 4. None of the above
All of the above.
Which polysaccharides are comprised of branched polymers?
Amylopectin (less branched) and glycogen (more branched).
Which two polysaccharides compose of starch?
Amylose and Amylopectin
What are forms of plant polysaccharides?
Amylose and amylopectin.
What is the chemical formula for sucrose, if sucrose is a disaccharide of one glucose and one fructose monomer?
C12 H22 O11
How are starch and cellulose similar?
Both are comprised of glucose polymers. They both have 1-4 linkages.
Why can cows and termites digest cellulose?
Both have prokaryotes in their G.I. tract that can digest cellulose for their hosts.
What reaction is used to join to glucose molecules to form Maltose?
Dehydration reaction.
Lactose is a __________ (mono -, di- or polysaccharide)?
Di
Sucrose is a __________ (mono -, di- or polysaccharide)?
Di
Name three Ketoses.
Dihydroxyacetone, Ribulose, Fructose.
What do you call two monosaccharides joined by a covalent bond?
Disaccharide.This covalent bond is specifically called a glycosidic linkage. This occurs by a dehydration reaction.
Name three Hexoses (C6 H12 O6).
Glucose, Galactose, Fructose.
Name two Trioses (C3 H6 O3).
Glyceraldehyde, Dihydroxyacetone.
Name four Aldoses.
Glyceraldehyde, ribose, glucose, galactose
What molecule is used for short term energy storage in animals?
Glycogen
How is an outflow glucose different from a beta glucose.
In alpha glucose the hydroxyl group at carbon one is below the plane of the ring. In beta glucose the hydroxyl group at carbon one is above the plane of the ring.
A linear carbon skeleton is a convenient representation of a variety of monosaccharides, but it is not completely accurate because...
In aqueous solutions, monosaccharides form rings. In the example of glucose, carbon 1 bonds to the oxygen attached to carbon 5.
How do you determine whether the sugar is an aldehyde sugar or a ketone sugar?
It depends on the location of the carbonyl group. An aldehyde sugar/aldose has a carbonyl group on carbon 1. A ketone sugar/ketose has the carbonyl group on carbon 2.
What is glycogen?
It is an animal polysaccharide comprised of glucose. It is more extensively branched than amylopectin.
A ketose sugar is also known as what?
Ketone sugar
Where is glycogen usually found?
Liver and muscle cells.
Fructose is a __________ (mono -, di- or polysaccharide)?
Mono
Glucose is a __________ (mono -, di- or polysaccharide)?
Mono
What is the simplest form of carbohydrates?
Monosaccharides (single saccharide/sugar)
What is the difference between glucose and galactose?
The location of the -H and -OH around carbon4.
What are isomers?
Two or more compounds having the SAME MOLECULAR FORMULA but different structural arrangement of molecules resulting in different properties.
Name some examples of carbohydrate isomers.
glucose (C6H12O6) galactose (C6H12O6) fructose (C6H12O6)
Examples of monosaccharides
glucose, galactose, fructose, ribose