chem chapters 14 + 15 (carbohydrates, saccharides, monosaccharides, glucose, stereochemistry, disaccharides, polysaccharides, lipids, fatty acids, saponifiable lipids, triacylglycerols, fluid mosaic model, nonsaponifiable lipids)

life processes

biochemistry is the chemistry of ______ __________

organic; inorganic

biochemistry involves ________ and __________ molecules

empirical formula

C * H₂O

examples of carbohydrates

sugar, starch

photosynthesis

energy from the sun is used by green plants to convert CO₂ and water into carbohydrates

photosynthesis

what reaction is this?

6CO₂ + 6H₂O ^{light energy}→_{plant enzymes chlorophyll} C₆H₁₂O₆ + 6O₂

6CO₂ + 6H₂O

what are the reactants in photosynthesis?

? ^{light energy}→_{plant enzymes chlorophyll} C₆H₁₂O₆ + 6O₂

C₆H₁₂O₆ + 6O₂

what are the products in photosynthesis?

6CO₂ + 6H₂O ^{light energy}→_{plant enzymes chlorophyll} ?

aldehydes; ketones

carbohydrates are defined as polyhydroxy __________, polyhydroxy _________ or compounds that can be hydrolyzed to them

examples of compounds that can be hydrolyzed

acetals, hemiacetals

“-ose”

carbohydrates typically end in _____

monosaccharide

simple sugars; a monomer

examples of monosaccharides

glucose, galactose, fructose

disaccharide

contains two monosaccharide units chemically united

examples of disaccharides

sucrose, maltose, lactose

what two sugars is sucrose made of?

glucose and fructose

what two sugars is maltose made of?

glucose and glucose

what two sugars is lactose made of?

glucose and galactose

polysaccharide

contains many monosaccharide units chemically united; usually these chemical bridges are made of glucose units.

examples of polysaccharides

starch, glycogen, and cellulose

what is the first function of carbohydrates?

provide and store energy

what is the second function of carbohydrates?

act as structure for cells

what is the third function of carbohydrates?

supply carbon atoms for the biosynthesis of other molecules

general formula for monosaccharides

(CH₂O)_n where n = 3 to 7

(CH₂O)₆ → C₆H₁₂O₆

what would the general formula of hexose be? (CH₂O)_n where n = 3 to 7)

aldose

a monosaccharide that is an aldehyde derivative

ketose

a monosaccharide that is a ketone derivative

open chain; cyclic chain

equilibrium exists between two types of glucose. what are these two types?

in the open chain, C1 is eletrophilic (attracts e^-) and -OH on C5 is nucleophilic (donates e^-). the C=O bond breaks, allowing -OH to bond with C1. this process creates a hemiacetal (C-O-C-OH) where C1 and C5 are joined by an oxygen bridge, completing the cyclic ring structure.

how does glucose go from an open chain to a cyclic ring?

oxygen

what atom joins carbon 1 and carbon 5 together in a cyclic ring?

hemiacetal

C-O-C-OH

acetal

C-O-C-O-C

up (β); down (α)

when glucose is placed in solution, the aldehyde functional group on C1 reacts with the hydroxy group on C5 which forms a hemiacetal. what are the two ways to place the hemiacetal?

anomer

a type of stereoisomer (molecules with the same formula but different 3D structures) that differ specifically in the orientation of the –OH group at the anomeric carbon (carbon 1 in glucose).

stereoisomers

compounds that have the same structural formula, however their atoms have a different arrangement in space.

enantiomers

compounds that contain at least one chiral carbon and exhibit the property of “handedness”

β-D-glucose

is this α-D-glucose or β-D-glucose?

α-D-glucose

is this α-D-glucose or β-D-glucose?

anomers

α-D-glucose or β-D-glucose are what type of stereoisomers?

asymmetric; farthest

D and L classification is according to the configuration around the _____________ carbon _________ from the carbonyl carbon

right

the D classification means that the -OH group on the carbon furthest from C=O is on the _______ side

left

the L classification means that the -OH group on the carbon furthest from C=O is on the _______ side

α-D-glucose

is this α-D-glucose or α-L-glucose?

α-L-glucose

is this α-D-glucose or α-L-glucose?

the bond that follows C5→C4 through the glycosidic linkage (C5-O-C1-O-C4)

where is the acetal located?

the bond where both monosaccharide units are joined (C1-O-C4)

where is the glycosidic linkage located?

down, up, down (DUD)

what -OH configuration does glucose follow?

up, up, down (UUD)

what -OH configuration does galactose follow?

Ag

reducing sugars produce ___ with Tollens’ reagent

Cu₂O

reducing sugars produce ______ with Benedicts’ or Fehlings’ reagent

maltose

glucose + glucose → ?

glucose + glucose

? + ? → maltose

maltose formation

polymers

polysaccharides are large _________ formed from monosaccharides bonded to each other by glycosidic linkages. all polysaccharides are non-reducing sugars.

they contain an acetal which cannot be reduced

why are polysaccharides non-reducing sugars?

starch

a mixture of two kinds of bipolymers of α-D-glucose found in plants

yes

is starch found in plants?

amylose (linear)

unbranched chains composed of 250 to 4000 α-D-glucose units joined by α(1→4) glycosidic linkages

amylopectin (branched)

chains composed of more than 100,000 α-D-glucose units joined by α(1→4) and α(1→6) glycosidic linkages

amylose test

add I2 in KI solution. a positive test will show dark blue.

glycogen (highly branched)

resembles amylopectin except more highly branched with α-D-glucose units joined more frequently by α(1→4) and α(1→6) glycosidic linkages. it is the glucose (energy) storage carbohydrate in the animal kingdom

cellulose (linear)

the most abundant polysaccharide and a major component of the cell wall of higher plants. the β-D-glucose units are held together by β(1→4) glycosidic linkages

amylose; amylopectin

what are the two kinds of bipolymers of α-D-glucose found in plants?

lipids

substances that are insoluble in water and can be extracted from cells by a nonpolar solvent. they are greasy, nonpolar, and hydrophobic.

insoluble

are lipids insouble or soluble in water?

simple lipids

waxes, fat, oil

complex lipids

phospholipids, glycolipids, steroids

solubility

lipids are categorized based on ___________

saponifiable lipid

a lipid which contains an ester (RCO₂R’) that can be hydrolyzed to yield a carboxylic acid (RCO₂H) and an alcohol (ROH), or treated with a strong base to yield a carboxylate salt (RCO₂^-) and an alcohol (ROH)

nonsaponifiable lipid

a lipid which does not contain an ester (RCO₂R’), therefore CANNOT be hydrolyzed or saponified

examples of saponifiable lipids

waxes, triacylglycerols, triglycerides

examples of nonsaponifiable lipids

steroids, terpene, testosterone

first function of lipids

structural components of membranes

second function of lipids

storage and transport forms of fuel

third function of lipids

protective coatings (cell membrane phospholipid bilayer, sebum, myelin sheath in nerves, adipose tissue that cushions organs)

fourth function of lipids

shock absorbers

fifth function of lipids

insulation

sixth function of lipids

chemical messengers

fatty acid

long hydrocarbon chains that end with a carboxyl group

saturated fatty acid

long hydrocarbon chains containing single bonds that end with a carboxyl group

terminal

the carboxyl group which is located at the end of a hydrocarbon chain in a fatty acid

general formula for saturated fatty acids

R-COOH (carboxylic acid) where R is a long unbranched chain usually with an even # of carbons

examples of saturated fatty acids

palmitic acid, stearic acid

they follow the form R-COOH and are saturated meaning they do not contain double bonds

why are palmitic acid and stearic acid categorized as saturated fatty acids?

palmitic acid formula

*follows the form R-COOH

(C₁₆ acid)

CH₃(CH₂)₁₄-COOH

the methyl group at the end of the hydrocarbon chain

in palmitic acid, CH₃(CH₂)₁₄-COOH, what does CH₃ stand for?

14 carbon groups

in palmitic acid, CH₃(CH₂)₁₄-COOH, what does (CH₂)₁₄ stand for?

the carboxyl group at the terminal end

in palmitic acid, CH₃(CH₂)₁₄-COOH, what does -COOH stand for?

stearic acid formula

*follows the form R-COOH

(C₁₈ acid)

CH₃(CH₂)₁₆-COOH

unsaturated fatty acid

fatty acids that contain one or more double bonds in their hydrocarbon chain and end in a carboxyl group

examples of unsaturated fatty acids

oleic acid, linoleic acid

oleic acid formula

(18:1^Δ9)

CH₃(CH₂)₇CH=CH(CH₂)₇-COOH

monosaturated

1 double bond in the hydrocarbon chain

polysaturated

more than 1 double bond in the hydrocarbon chain

linoleic acid formula

(18:2^Δ9,12)

CH₃(CH₂)₄CH=CHCH₂CH=CH(CH₂)₇-COOH

unsaturated fatty acid nomenclature

# of carbon:# of double bonds^{position of double bonds}

→ fatty acid containing 18 carbons with 1 double bond on carbon 9 → 18:1^Δ9

carbon 9

where is the position of the double bond located on this fatty acid?

18:1^Δ9

wax

the simplest saponifiable lipid

ester general formula

where R and R’ are long chain hydrocarbons

examples of waxes

beeswax, lanolin