Biology: Polymers and Carbohydrates

Study Notes

Monomers form larger molecules by condensation reactions called dehydration reactions, removing a water molecule and forming a new bond.
Dehydration reaction is the process of forming a polymer.
Polymers can disassemble by hydrolysis, adding a water molecule and breaking a bond.
Carbohydrates are biomolecules consisting of carbon, hydrogen, and oxygen atoms, usually with the general formula Cn(H2O)n = CnH2nOn.

Macromolecules are large molecules consisting of many smaller structural units linked together by a process called dehydration synthesis.
All biological macromolecules are made up of a small number of elements: carbon, hydrogen, oxygen, nitrogen, and phosphorus.
Polymers are chain-like molecules called macromolecules formed by covalent bonds between monomers.

Monosaccharides are the simplest carbohydrates, composed of a single sugar unit according to the formula CnH2nOn.
Monosaccharides can be classified according to the number of carbon atoms present in the monosaccharide.
Monosaccharides can be classified according to whether they contain an aldehyde or keto group.

Stereoisomers are compounds having the same structural formula but differing in the arrangement of atoms in the molecule in space.
Chiral carbon is a carbon atom attached to four different groups.
Optical activity is the ability of a chiral molecule to rotate the plane of plane-polarized light.

Glucose is a major source of energy for humans and animals.
The body maintains a fairly constant blood glucose level of 70-140 mg/dl at all times.
Glucose can be converted into other sugars in the liver and other tissues.
Galactose is synthesized in the mammary gland to form the disaccharide lactose.
Fructose is present in semen and is a constituent of the disaccharide sucrose.
Ribose forms part of the structural backbone of nucleic acids RNA and DNA.

Disaccharides are composed of two monosaccharides joined by a covalent bond.
Common disaccharides are sucrose, lactose, and maltose.
Starch is a polymer consisting entirely of glucose monomers.
Glycogen is the major storage form of glucose in animals.
Cellulose is a polymer of glucose with different glycosidic linkages than starch.

Sugars, after being hydrolyzed by salivary amylase, provide substrate for the actions of oral bacteria.
Oral bacteria produce excess amounts of acid, which starts attacking tooth enamel, eventually leading to cavities and tooth decay.