3 Macromolecules - Protein, Carbohydrates

Hydrolsis Reaction

when a water molecule is inserted across a covalent bond and breaks it resulting in a split H2O. One polymer gains a H atom and the other a OH- molecule.

What is the purpose for a hydrolysis reaction?

to break down complex molecules into simpler components so enzymes have an easier time breaking them down for digestion. (breakdown of polymers)

Condensation or Dehydration reactions

release of a molecule of water and the formation of a covalent bond on 2 monomers

What is the purpose of a dehydration/condensation reaction? 

joins two molecules to form a compound, H2O. helps with polymer synthesis and forming a macromolecule.

Polymer

a chain of monomers linked together by covalent bonds

Monomer

small units chemically bonded to make polymers

What type of chemical reaction adds monomers to lengthen polymers?

dehydration/condensation reaction

What type of reaction removes monomers to shorten polymers? 

hydrolysis reaction

Carbohydrates

• represented by the formular (CH2O)n

• n is the number of carbon atoms in the molecule

• 3 types: monosaccharides, disaccharides, polysaccharides

What are the monomers and polymers of carbohydrates called? 

monomer: monosaccharides

polymer: disaccharides & polysaccharides

Monosaccharide

• may exist as a linear chain or ring-shaped in aqueous solutions

• polar because of OH-

• Ex. glucose, fructose

Glucose

• glucose monomers in long branches

• important source of energy in living species (ATP)

• an aldehyde - carbonyl is at the end of the carbon skeleton

• stored in liver and muscle

• C6H12O6

Disaccharide 

• formed when two monosaccharides undergo a dehydration reaction

• covalent bond = glycosidic bond

• Ex. maltose, sucrose (table sugar)

Maltose

glucose + glucose

Sucrose

glucose + fructose

Polysaccharide 

• Polymers of sugar

• can be branched or unbranched

• Storage and structural roles

• Ex. cellulose, glycogen, starch (glucose monomers in long chains)

Amylose

linear polysaccharide

Amylopectin

branched polysaccharide 

Starch

• storage polysaccharide

• glucose monomers in long chains

• amylopectin 

• synthesized by plants → stores excess glucose in roots and seeds

• easily digestible 

Glycogen

• storage polysaccharide

• glucose monomers in long branches 

• used by animals → store excess glucose 

• stored in liver and muscle cells 

• easily digestible

Cellulose

• structural polysaccharide 

• every other glucose monomer is flipped over and packed tightly as extended long chains

• rigid and has high tensile strength important for plant cells

• cell walls of plants are mostly made of cellulose

• cellulase can break down cellulose into glucose which is used as an energy source by the animal

Sugar Isomers

• same molecular formula, but different structure

• Ex. glucose and fructose are structural isomers

Starch breakdown

Starch is broken down to maltose by enzymes called amylases found in your saliva and your small intestine. maltase breaks down maltose into glucose. Glucose is absorbed by the cells lining the small intestine.

Protein

• most abundant organic molecules in living species

What are the monomers, polymers, and covalent bonds of protein?

• Monomer: amino acid

• Polymer: Polypeptide 

• Covalent bond: Peptide bond

What are the three groups that can be found attached to the central carbon of an amino acid?

Carboxyl group, animo group, hydrogen atom

How do amino acids differ from each other?

The side chain is different in each aa. Based on this, the aa could be hydrophobic, hydrophilic, acidic (-), or basic (+)

How many standard aa are there?

20

How are protein structure and function related?

The sequence of amino acids determines the shape of the protein and its function. If even one aa is changes in the structure, the function of the protein can change.

Primary Protein Structure

• dehydration/condensation that formed peptide bonds

• amino acid sequence

• n-terminal (NH2) and c-terminal (COOH)

Secondary Structure

• a helix and B-pleated sheets

• amino acid subunits 

• hydrogen bonds between parts of peptide backbone causes the aa to fold into a repeating pattern.

Tertiary Structure

• due to side chains interactions

• a helix and B-pleated sheets folded together

• Hydrophobic Interactions: amino acids “push” into middle

• Weak bonds: hydrogen bonds, ionic bonds

• Disulfide bridges: covalent bonds between -SH groups or separate cysteine amino acids 

Quaternary Structure

• 2+ polypeptide chains form one macromolecule

• can be the same or different 

• composed of multiple tertiary structures that interact and form 

• Ex. fibrous (3 subunits), globular (a chains and b chains)

Protein Denaturation

occurs when protein is subject to changes in temperature, pH, or exposure to chemicals. The structure may change and lose its shape. It can be reversible because the primary structure is often preserved, allowing it to continue its function

Ex. egg (heat causes vibration causing it to lose its shape)