B1.1: Carbohydrates and Lipids

Carbon Bonding

Carbon can form up to 4 (single or double) covalent bonds, done by sharing electrons

covalent bonds = strongest bonds

Carbon in Organic Compounds

Carbon binds to other carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur (CHNOPS)

fully single bonded carbon forms tetrahedron structure

Carbon can form branched/unbranched chains and single/multiple rings

Metabolism and Functions (2)

Sum of all chemical reactions that occur within an organism

Functions: energy for cellular processes, synthesis and assimilation of new materials

Anabolism

Joining of simple molecules (monomers) to produce complex ones (polymers)

Done via Condensation Rxn

Endergonic, requires energy

Condensation Rxn

Removal of H20 to link bonds, water formed from OH (hydroxyl) from one monomer and H from another

Catabolism (digestion)

Breaking of complex molecules (polymers) to produce simple ones (monomers)

Done via hydrolysis

Exergonic, releases energy

Hydrolysis

A chemical process that splits a molecule by adding water.

Carbohydrate Monomers/Polymers

Monomer: Monosaccharide

Disaccharide (2)

Polysaccharide (many)

Linking of Monosaccharides

Forms a glycosidic bond (covalent bond C-O-C) via a condensation rxn

Monosaccharides Function & Example

Function: Short-term energy storage (ex. glucose)

Glucose exists in both linear and ring (hexose, 6-cornered ring) formation

Glucose Characteristics

Soluble, therefore easily transported in medium like blood

Chemically Stable

Affects osmotic gradient and converted into starch or glycogen to prevent this

Yields energy when oxidized (lose electron)

Storage/Structure Polysaccharides in Plants/Animals

Plant Storage - starch, alpha

Plant Structure - Cellulose, beta

Animal Storage - Glycogen, alpha

Animal Structure - Chitin, alpha

Starch

Made alpha glucose, plant energy storage, either amylose or amylopectin

Amylose

Unbranched, helical (1-4 bonds), compact, more difficult to digest, preferred storage form

Amylopectin

Branched, 1-4 and 1-6 Bonds (1-6 bonds cause branch), easier to digest bc more Surface Area

Glycogen

animal energy storage, made of alpha glucose

Unbranched (1-4) and branched (1-6) linkages

Found in liver in animals

Similar to amylopectin, but more branched, coils for good storage

Starch and Glycogen Characteristics

1-4 linkages (linear) and 1-6 linkages (branched)

Single glucose can be removed (hydrolysis) or added (condensation rxn) w/ ease

large in size, but relatively compact due to coiling and branching

low solubility, therefore does not interfere with the osmotic gradient of a cell

Cellulose

plant structure, made of beta glucose

Unbranched (1-4 bonds)

Found in plant cell walls

Indigestible for most (lack enzyme) therefore "fiber"

Alpha vs. Beta Glucose

structural isomers (same molecules, different structures)

Position of hydroxyl on C1 is different for alpha/beta

For beta glucose, for condensation rxn to occur, newly added one must be inverted.

Beta-Glucose Characteristics

Bc alternating directions (bc of inversion), produces a straight chain

Forms bundles arranged in parallel, then regularly spaced OH groups allow additional hydrogen bonds with adjacent strands (forms a sheet structure)

Such Cross Link provides high tensile strength for plant cells to withstand high water pressures

Images of Glucose Polymers

Glycoproteins

Polypeptides with oligosaccharides (short sugar chain), found in plasma membrane of animal cells, facing outside

Distinctive glycoproteins allow cells to be recognized by other cells

aids in organization of tissues and identifies/destroys infected cells

ABO Glycoproteins

Red blood cells have glycoproteins that affect transfusion

Three types, A, B, O

Blood with glycoprotein A (antigen) will be rejected y someone who does not produce it (antibody)

Blood w/ glycoprotein O will not be rejected bc it is the same structure as A and B but without one monosaccharide

Blood Type A

A antigen, makes B antibodies so destroy B

Blood Type B

B antigen, makes A antibodies so destroy A

Blood Type O

Both antibodies, universal donor

Lipids

Include fats, oils, waxes, and steroids

Hydrophobic, more attracted to nonpolar (not necessarily repelled by H2O

DOES NOT CONSIST OF MONOMERS AND POLYMERS

Triglycerides Formation

Condensation Rxn joins ONE glycerol and THREE fatty acids

OH (hydroxyl) of glycerol and COOH (carboxyl) of fatty acid forms ester bonds

Ester Bonds

bond between fatty acids and glycerol, 3 H2O produced when 1 triglyceride made

Hydroxyl on glycerol loses H, carboxyl on fatty acid loses OH to form H2O

Phospholipids

Polar head composed of phosphate (instead of 3rd fatty acid), 2 nonpolar fatty acid tails

Amphipathic, both hydrophilic (water-loving) and lipophilic (fat-loving)

Lipophilic

fat-loving, similar to hydrophobic

Fatty Acids Characteristics

Long hydrocarbons, consist of only C and H

CH3 (methyl) at one end and COOH (carboxyl) on the other (OH of carboxyl falls off to form H2O in condensation rxn)

Vary in number of hydrocarbons and double bonds

Saturated Fatty Acids

No double bonds, "saturated" with hydrogens

Linear, come from animal sources

High melting point - solid at room temperature

Unsaturated Fatty Acids

Has double bonds, therefore bent

Come from plant sources

Low melting point - liquid at room temp (typically)

Monounsaturated/Polyunsaturated Fatty Acids

Mono = 1 double bond

Poly = more than 1 double bond

Cis Unsaturated Fatty Acids

Two H atoms adjacent to double bond are on the same side, hydrogens repel one each other, forming kinks

liquid at room temperature

Trans Unsaturated Fatty Acid

Two H atoms adjacent to double bond are on different sides, produced in industrial process called hydrogenation (now banned)

Makes fats "spreadable" such as margarine

Linear and solid at room temp, despite double bonds

Cis vs Trans Unsaturated Fatty Acids

Lipid Advantages (6)

Function - long-term energy storage in adipose tissue

Chemically stable, energy not lost over time

Immiscible in H2O, no effect on osmotic pressure of cell

Store 2x energy as carbs

poor heat conductors, used as thermal insulators such as blubber

Act as shock absorbers