ABI102 HACKMANN 2

monosaccharides are most commonly what

most monosaccharides are hexoses or pentoses

monosaccharides range from how many carbons

3-8 carbons

monosaccharides include what kind of bonds

aldoses and ketoses

aldose is

are carbonyl at the end of carbon chain (aldehyde group)

ketose is

carbonyl elsewhere (in ketone group)

what is a chiral center

carbon with four different substituents

why is chiral center significant

helps determines type of monosaccharide

chiral centers in red

what is an epimer

a type of chiral center that differs at one chiral center

what is an enantiomers

chiral centers at all carbons differ, *in fact, most carbohydrates live in organisms are d-isomers

T or F monosaccharides can have s straight chain but also cyclic structure?

true!

what are the type of cyclic structures that monosaccharides have

B anomer:

• -Oh of anomeric (carbonyl) C up

  • same side as C-6

a anomer

• -OH of anomeric C down

  • opposite side from C-6

what is the importance of a and b anomers?

Anomeric configurations helps determine the structural properties of carbohydrates

starch (good for eating)

• contains an a-glucose

cellulose (good for wearing)

• contains a b-glucose

some monosaccharides are reducing sugars

it can easily reduce copper ions (Cu2+) or other ions

• sugar is itself oxidized during the process

Sit of oxidation is anomeric carbon (carbonyl)

• oxidized to carbonxyl

Example: glucose

how were they able to tell how many sugars in monosaccharides

they detected using an oxidizing agent that turns color when reduced

• they used the common agent of (DNS) 3.5-dinitrosalicylic acid

  • this is important historically in detecting diabetes

monosaccharides have a lot of dervatives

• hydroxyl group can be replaced w/ absent substituent, carbon can be oxidized or hydroxyl can be phosphorylated

  • amino acids

    • -OH→ -NH₂

  • deoxy sugars

    • -OH→ -H

  • acidic sugars

    • -CH₂OH→ COO^-

  • sugar phosphates

    • -OH→ -OPO₃^2-

examples of monosaccharides have derivatives

image of derivatives

how are disaccharides formed?

combination of monosaccharides

specifically, the anomeric carbon of one monosaccharide is linked with another and its linkage is called a glycosidic bond

some common disaccharides

1. maltose (starch)

2. lactose (milk)

3. sucrose (from photosynthesis)

4. cellobiose (cellulose)

where does glycosidic bond named by

1. position of carbon involved

2. anomeric configuration of those carbons

3. maltose: Glc(a1→4)Glc

name more examples of glycosidic bonds

maltose: Glc(a1→4)Glc

cellobiose: Glc(B1→4)Glc

sucrose: Glc(a1<→B2)Glc

lactose: Glc(B1→4)Glc

what is the glycosidic bond here?

Glc(a1→a)Glc

table of disaccharides

image of table

what is a reducing sugar?

it is the end of a disaccharide with free anomeric carbon

this is detected in DNS or other oxidizing agent

is there always a reducing end?

no! for example sucrose, its resistance to oxidation makes sucrose good storage compound in plants

there are some examples of polysaccharides are important what is one of them?

cellulose— its the most abundant in the world

along with cellulose, what is another important biomolecule?

chitin—it’s the second most abundant biomolecule on earth

polysaccharides can take one many forms, what are the 4 structural classes

homopolysaccharides, heteropolysaccharides, branched, unbranched

what are the functional classes

storage, structural, and other

what are the specific storage examples in functional classes

starch, glycogen,fructan

one of two specific starch is

amylose

• unbranched Glc(a1→4)Glc

two of two specific starch is

amylopectin

• includes Glc(a1→ 6)Glc branches every 24 to 30 residues

fill-in-the-blank: corn starch is ___ amylose and ___ amylopectin

24%, 76%

glycogen is similar structure to what?

amylopectin, but more frequent branching (every 8 to 12 residues)

the second storage glycogen can be found where?

in animal liver and muscle

• fun fact: it can also be found in microbes (glycogen granule in liver)

in glycogen what are the reasons glucose are found in polysaccharides

• it protects cell from high osmolality

• glycogen in human liver

  • if hydrolyzed, it would form concentrated (0.4M) glucose solution

    • (high, burst all cells from liver, water will enter cells)

  • this would burst the cell

the third storage fructan linkage is what

Fru(b2→6)Fru and Fru(B2→1)Fru

fructan can be found where

plants (up to 30% of grass dry weight (ex.horses))

fructan solubility is what?

slightly to highly soluble

the second function classes storage examples is what?

• cellulose

• hemicellulose

• pectin

• b-glucan

• chitin

• peptidoglycan

• agarose

while cellulose brings structural support, its linkage is called

Unbranched Glc(B1→4)Glc

• it’s identical to amylose, except linkage is B

cellulose is…

Tough, Insoluble, and indigestible

cellulose can be found in

Cotton and Plant cell wall (with other polysaccharides)

the plant cell wall in cellulose has other components of what (1 of 4)

hemicellulose

• xylose core: Xy1(B1→4)Xyl

• branches that include arabinose and other sugars

the plant cell wall in cellulose has other components of what (2 of 4)

pectin

• Galacturonic acid core: GalA(a1→4)GalA

• Branches that include arabinose, galactose, and other sugars

the plant cell wall in cellulose has other components of what (3 of 4)

B-glucan (not shown)

• Glc(B1→4)Glc core with Glc(B1→3)Glc branches *Similar to cellulose

• found in plants and microbes

the plant cell wall in cellulose has other components of what (4 of 4)

Lignin→ a part of the cell wall

• not a carbohydrate

  • polyphenolic compound

plant cell wall facts

• indigestible by mammalian enzymes

• digestible by

  • gastrointestinal microbes (in conc break down glass)

  • some arthropods (termites produce enzyme)

chitin linkage is what?

unbranched N-acetylglucosamine GlcNAc(B1→4)GlcNAc

chitin is found in

exoskeletons of arthropods

peptidoglycan(antibacterial agent) linkage is what?

unbranched N-acetylglucoseamine and N-actylmuramic acid: GlcNAc(B1→4)Mur2Ac

peptidoglycan contains what

(croslinked to) peptide side chain

peptidoglycan founded where

in cell wall of bacteria

peptidoglycan is broken down by

lysozyme in human tears

Agarose is made up of

• made up of D-galactose and an L-galactose derivative

• contains charged groups (sulfates and pyruvates)

Agarose is comes from

red algae

Agarose is used in

gel electrophoresis

other: glycosaminoglycans made up from

made up alernating aciidic and amino sugars

some contain charged groups (sulfates), forcing an extended configuration

example: chondroitin sulfate

other: glycosaminoglycans come from where

polysaccharides from the extracellular matrix of animals

• extracellular matrix: space between the cells

glycosaminoglycans exist

not in free form, rather, attached to proteins to form proteoglycans

• roles in cell include

  • adhesion

  • recognition

  • signaling

oligosaccharides are covalently attached to glycoproteins (1)

• they’re rare except when attached (covalently) to proteins

  • attachment is called glycosylation

  • proteins formed are glycoprotein

    • common in mammals

      • make up 50% of total proteins

oligosaccharides are covalently attached to glycoproteins (2)

• oligosaccharides are short and highly branched

• acetylated residues (e.g., N-acetylglucoseamine) common

• carbohydrate-protein linkage involves

  • ser/thr or Asn on protein

  • O- or N- on oligosaccharide

glycoproteins example

mucins

• component of mucus

• hold water and form gels

glycoproteins recognized by

• viruses

• toxins

• bacteria

• other mammalian cells (e.g., leukocytes)

glycoproteins important

important to virulence and immunity

Lipids I: Lipids are structurally diverse

definition of lipids: biomolecules are soluble in organic solvents

• ether, benzene, chloroform

otherwise, no shared feature

Lipids I: structures and properties of lipids that contain fatty acids

1. fatty acids themselves

2. triacylglycerols

3. waxes

4. membrane lipids

Lipids I: classification

lipids that contain fatty acids

• fatty acid themselves

• triacylglycerols

• waxes

• membrane lipids

lipids that don’t contain fatty acids

• sterols

• fat soluble vitamins

• pigments

• polyketides

Lipids I: fatty acids are a major class, what is the nomenclature rules ( lipid number)

• fatty acid= carboxylic acids with hydrocarbon chains between 4 to 36 carbons

• saturated

  • no double bonds

• unsaturated

  • one more double bonds

Lipids I: fatty acids are a major class, what is the nomenclature examples ( lipid number)

• nomenclature (lipid number)

  • palmitic acid (16:0)

    • 16 c

    • 0 double bonds

  • oleic acid (18:1 cis-9)

    • 18 c

    • 1 double bond in cis configuration beginning at c9

Lipids I: fatty acids are a major class, question examples

(14:0), (16-1 cis-9)

Lipids I: fatty acids (Omega-3) example

• double bond at 3rd carbon from end of the chain

• example: a-linoleic acid

  • lipid number

    • usually written as 18:3 (n-3) → less info, specificity

    • could be written as 18:3 all cis-9,12.15

Lipids I: fatty acids (Omega-3) importance

• many required in diet

  • a-Linolenic acid

    • cannot be synthesized

      • animals lack the desaturase enzymes to form the unsaturated bonds→ causes deficiency

  • Eicosapentanoic acid (EPA) (20:5 n-3)

    • can be synthesized from a linolenic acids if enough of this precursor

    • otherwise required in diet

  • Docosahexaenoic acid (DHA) 22:6 n-3)

    • same as EPA

  • Deficiency causes dermatitis, skin lesions, poor growth, reproductive failure

Lipids I: fatty acids (Omega-6) example

• double bond at 6th carbon from end of chain

• example: linoleic acid

  • lipid number

    • usually written as 18:2 (n-6)

    • could be written as 18:2 cis,cis-9,12

Lipids I: fatty acids (Omega-6) importance

• many required in diet

  • linoleic acid

  • Arachidonic acid (AA) (20:4 n-6)

    • if not enough linoleic acid avaliable as a precursor

    • always required by cats

      • cats lack enzymes to synthesize from linoleic acid

• omega-3 and omega-6 rich in fish oil

Lipids I: fatty acids (Conjugated linoleic acid (CLA)) importance

• family of 28 isomers of linoleic acid

• have conjugated double bonds

  • alternating double and single bonds

• formed in rumen by microbes

  • process known as biohydrogenation

Lipids I: fatty acids melting point (1 of 2)

• decreases as the number of unsaturated bonds increases

• decreases as the chain length decreases

Lipids I: fatty acids melting point (2 of 2)

• decreasing as the number of unsaturated bonds increases

  • especially for unstaturated bonds in cis configuration

    • kinks prevent close packing of fatty acids

Lipids I: what stores fatty acids?

triacylglycerol= ester of glycerol and fatty acids

location of most fatty acids stored in cells

Lipids I: triacylglycerols about

• major form of energy storage in plants and animals

• used over polysaccharides because fatty acids

  • are more reduced carry more energy per carbon

  • are nonpolar and carry less water per gram

Lipids I: waxes store fatty acids and repel water (about)

• ester of long-chain fatty acids with long-chain alcohols

• insoluble and have high melting points

Lipids I: waxes store fatty acids and repel water (functions)

• storage of fatty acids in plankton

• protection and pliability for hair and skin in vertebrates

• waterproofing of feathers in birds

• protection from evaporation in plants

• useful as lotions, ointments, and polishes

Lipids I: membrane lipids envelope cells

• components of the membrane of cels

• types

  • phospholipids

  • glycolipids

  • archaeal ether lipids

Lipids I: membrane lipids envelope cells (phospholipids 1 of 6)

• similar structure to triacylglycerol but

  • one fatty acids substituted with polar head group

  • backbone may or may not be glycerol

    • backbone is glycerol in glycerophospholipids

    • backbone is sphingosine in sphingolipids

Lipids I: membrane lipids envelope cells (phospholipids 2 of 6)

• polar head group

  • contains phosphate

  • may contain other constituents (X)

Lipids I: membrane lipids envelope cells (phospholipids 3 of 6)

head groups of glycerophospholipids

Lipids I: membrane lipids envelope cells (phospholipids 4 of 6)

head groups of sphingolipid

Lipids I: membrane lipids envelope cells (phospholipids 5 of 6)

phosphotidylcholine

• A glycerophospholipid

• has phosphocholine head group

• one fatty acid is usually unsaturated

• major membrane lipid for animals

• absent in most bacteria

  • lack enzymes for synthesis of choline

Lipids I: membrane lipids envelope cells (phospholipids 6 of 6)

• sphingomyelin

  • a sphingolipid

  • like phosphotidylcholine, has a phosphocholine head group

Lipids I: membrane lipids envelope cells (glycolipids 1 of 3) about

• similar structure to phospholipids but

  • polar head group is carbohydrate, not phosphate

Lipids I: membrane lipids envelope cells (glycolipids 2 of 3) example

• galactolipids

  • polar head group is one or two galactose residues

  • major membrane lipid in plants

Lipids I: membrane lipids envelope cells (glycolipids 3 of 3)

• glycosphingolipids

  • polar head group is an oligosaccharide

  • determine blood types

    • o antigen= type o blood

    • a antigen= type a blood

    • b antigen = type b blood

  • difference is due to single residue

    • a antigen → extra N-acetylgalactosamine

    • b antigen→ extra galactose

Lipids I: membrane lipids envelope cells (Archaeal ether lipids 1 of 3)

• found in archaea

• unusual structure

  • don’t contain fatty acids

    • hydrocarbon is instead diphytanyl

  • contains 3 glyercol residues

    • one is a head group, and two are linked to the diphytanyl hydrocarbons

  • linkages are ether not amid or ester

Lipids I: membrane lipids envelope cells (Archaeal ether lipids 2 of 3)

• Diphytanyl groups

  • long (32 carbons) and span the entire membrane

    • don’t form lipid bilayer found in most organisms

Lipids I: membrane lipids envelope cells (Archaeal ether lipids 3 of 3)

• reasons for unusual structure

  • more stable under low pH and hot environments of some archaea

    • ether linkage more resistant to hydrolysis than ester

    • the lipid “unilayer” they form is more stable than a bilayer

Lipids II: structure and prpoperties of lipids that don’t contain fatty acids are

• sterols

• fat soluble vitamins

• pigments

• polyketides

Lipids II: sterols contain fused rings

• rings make up structure called steroid nucleus

  • 3 rings with 6 carbons

  • 1 ring with 5 carbons

  • structure is flat (planar) and rigid

• polar head group (hydroxyl group) and nonpolar side chains also present

Lipids II: what are the types of sterols

• cholesterol

• steroid hormones

• bile acid

• vitamin D precursors

Lipids II: sterol (cholesterol)

• most abundant sterol in animal tissue

• component of cell membranes

  • change fluidity of membrane

• can be obtained from diet or synthesized in liver

• transported in blood via lipoproteins

  • lipoproteins include HDL (good cholesterol), LDL (bad cholesterol), and others

Lipids II: sterol (steroid hormones)

• examples: estrogen and testosterone

• don’t contain alkyl side chain, so more polar than cholesterol

• synthesized from cholesterol in gonads and adrenal glands

• carried through the body in the bloodstream, usually attached to carrier proteins

• many are s*x hormones or reduce inflammation