Biochemistry exam 3
When two monosaccharides combine, the new C-O bond that joins the two rings together is called what?
Glycosidic linkage
What info does the term aldotriose tell you?
Has 3 C atoms and an aldehyde
What info does the term aldohexose tell you?
Has 6 C atoms and an aldehyde
What is a mixed triacylglycerol?
Have 2 or 3 different fatty acids
What are 3 types of non-hydrolyzable lipids?
Steroids, fat-soluble vitamins, and eicosanoids
What is another name for an alditol?
Sugar alcohol
Why is starch water soluble?
The OH groups aren't buried in a 3-D network, they are available for H-Bonding with H20 molecules.
What determines whether a tricylglycerol is a fat or an oil?
The identity of the 3 fatty acids
What is a glycogen?
The major form in which polysaccharides are stored in animals
Are fats solid or liquid at room temp?
Fats are solids at room temp
What is the difference between a fat and an oil?
Fats have higher melting points and they are solids at room temp. Oils have lower melting points and are liquids at room temp.
Fats are generally formed from fatty acids having ______ double bonds.
Few
Which monosaccharide combines with glucose to form sucrose?
Fructose
Which monosaccharide combines with glucose to form lactose?
Galactose
Are lipids generally polar or nonpolar?
Generally nonpolar
What is the repeating unit found in cellulose, starch, and glycogen?
Glucose
What product is formed when glycogen undergoes hydrolysis?
Glucose
What product is formed when starch undergoes hydrolysis?
Glucose
Which sugar is referred to when blood sugar is measured?
Glucose
Which sugar is the building block to form cellulose and starch?
Glucose
Which sugar, when metabolized, provides energy for our cells?
Glucose
What are the products of photosynthesis?
Glucose and oxygen
What are fatty acids?
They are carboxylic acids (RCOOH) with long carbon chains of 12-20 C atoms
What are essential fatty acids?
They cannot be synthesized in body and have to be obtained by diet.
What is a monounsaturated triacylglycerol?
They have a single C-C double bond
What is a polyunsaturated triacylglycerol?
They have more than 1 C-C double bond
What are saturated fatty acids?
They have no double bonds
What are unsaturated fatty acids?
They have one or more double bonds
What is a nonreducing sugar?
Those that don't react with Benedict's reagent
What is (about) the most number of C atoms found in a carbohydrate molecule?
Thousands
When are the prefixes D- and L- used before a carbohydrate name?
To distinguish the 2 enantiomers D-glyceraldehyde: naturally occurring enantiomer L-glyceraldehyde: unnatural isomers
What is a tricylglycerol?
Triesters formed from glycerol and 3 molecules of fatty acids
What is another name for a triacylglycerol?
Triglycerides
What is one common use of sorbitol?
Used as a sweetening agent
What does the term hydrophobic mean?
Water fearing
What does the term hydrophilic mean?
Water loving
Is starch water soluble or water insoluble?
Water soluble
Are lipids water-soluble or water-insoluble?
Water-insoluble
What are 3 subgroups of hydrolyzable lipids?
Waxes, triacylglycerols, and phospholipids
Liquid oils have a higher % of _________ fatty acids and are generally _________ in origin
unsaturated vegetable
Generally, are double bonds in naturally occurring fatty acids cis or trans?
Cis
What is a simple triacylglycerol?
Composed of 3 identical fatty acids
What are polysaccharides?
Contain 3 or more monosaccharides joined together
Glucose and all other naturally occurring sugars are what kind of sugars?
D-sugars
As the number of double bonds in the fatty acid increases, the melting point ________.
Decreases
Increasing the number of double bonds in the fatty acid side chains _________ the melting point of the triacylglycerol.
Decreases
What is another name for glucose?
Dextrose
What supplies the energy needed for photosynthesis to occur?
Energy from the sun
What functional group is found in most hydrolyzable lipids?
Ester
Naturally occurring fatty acids have an _____ number of carbon atoms.
Even
Does L-glucose occur in nature?
NO
Can humans digest cellulose?
No
Are oils solid or liquid at room temp?
Oils are liquids at room temp
What are biomolecules?
Organic molecules found in biological systems
Give two examples of an essential fatty acid
Palmitic and stearic acid.
Are unsaturated oils typically obtained from plant or animal sources?
Plant sources
Plants store glucose in the form of what?
Polysaccharides: starch and cellulose
Name two reactions that the aldehyde group in monosaccharides can undergo.
Reduction to an alcohol Oxidation to a carboxylic acid
The energy in glucose bonds is ________ when glucose is metabolized?
Released
Where is starch found?
Seeds and roots of plants
What is the common name of glucitol?
Sorbitol
Describe 2 important roles of lipids in biological systems
Source of energy and key component of cell membrane
Polysaccharides
Starch Carbohydrates that are made up of three or more monosaccharides Can be converted to simpler carbohydrates by hydrolysis
What suffix is usually used when naming monosaccharides?
-ose
Disaccharides are carbohydrates composed of what?
2 monosaccharides
The hydrolysis of a disaccharide cleaves the C-O glycosidic linkage and forms what?
2 monosaccharides
What are the 2 products formed when a disaccharide undergoes hydrolysis?
2 monosaccharides
How many C atoms are generally found in monosaccharides?
3-6 C atoms
Name the product of the reduction of the aldehyde group in a monosaccharide to an alcohol
Alditol
When the carbonyl group of an aldose is reduced to a primary alcohol, what is the general name of that product?
Alditol
Name the product of the oxidation of the aldehyde group in a monosaccharide to a carboxylic acid
Aldonic Acid
When the aldehyde group of an aldose is oxidized to form a carboxylic acid, what is the general name of that product?
Aldonic Acid
What are monosaccharides which include an aldehyde called?
Aldoses
All carbohydrates, except dihydroxyacetone, contain one or more _______?
Chirality centers
Are saturated fats typically obtained from plant or animal sources?
Animal sources
Name one common oxidizing agent used with carbohydrates
Benedict's Reagent
What are lipids?
Biomolecules that are soluble in organic solvents and insoluble in H2O
What are the reactants of photosynthesis?
CO2 and H2O
The oxidation of glucose is a multistep process that forms what?
CO2, H2O, and a great deal of energy
What does it mean to be a hydrolyzable lipid?
Can be converted into smaller molecules by hydrolysis with H2O
What are nonhydrolyzable lipids?
Cannot be cleaved into smaller units by aqueous hydrolysis; tend to be more varied in structure.
Largest group of organic molecules found in nature
Carbohydrates
Photosynthesis
Carbohydrates are synthesized (in green plants and algae) through this
What is a reducing sugar?
Carbohydrates that are oxidized with Benedict's reagent
Functional group found in all monosaccharides
Carbonyl group
Most of the insoluble fiber in our diet is?
Cellulose
Name three polysaccharides prevalent in nature
Cellulose, starch, and glycogen
What is an essential fatty acid?
Humans can't synthesize them and must be obtained from diet.
Where is cellulose found?
In the cell walls of nearly all plants.
What are monosaccharides which include a ketone called?
Ketoses
Disaccharides
Lactose Carbohydrates that are made up of two monosaccharides Can be converted to simpler carbohydrates by hydrolysis
Where in the body do humans store glycogen?
Liver and muscle
The larger the number of cis double bonds, the ______ the melting point.
Lower
Are all aldoses reducing sugars?
Yes
Are all ketoses reducing sugars?
Yes
Are fats and oils triacylglycerols?
Yes
Can glycogen undergo hydrolysis?
Yes
Can starch undergo hydrolysis?
Yes
Oils are generally formed from fatty acids having _______ double bonds.
a larger number of
Monosaccharides
glucose and fructose Cannot be converted to simpler carbohydrates by hydrolysis
