Biology: The Molecules of Life Ch. 3

Organic Compound

chemical compound containing carbon and usually hydrogen

What is the importance of Carbon to life’s molecular diversity?

Carbon can bond with four other atoms which is the basis for building large and diverse organic compounds

Carbon chains form the backbone of most organic molecules; can be branched in rings, straight, or double bond

Hydrocarbon

organic compound composed of only carbon and hydrogen

Isomer

have the same molecular formula but different structures and therefore properties

Importance of Isomers

adds to the diversity of organic molecules and their properties

Functional Group

affects molecules function by participating in chemical reactions

Chemical Groups 1-5

Hydroxyl, Carbonyl, Carboxyl, Amino, Phosphate

These groups are polar and hydrophilic

Chemical Group 6

Methyl

Not reactive, affects molecular shape and therefore function

Macromolecule/Polymer

large molecule consisting of many identical or similar monomers linked together by covalent bonds

Monomer

building blocks of polymers

Dehydration Reaction

links monomers together to form polymers by removing water molecules

Hydrolysis Reaction

polymers are broken apart by adding water to break the bond between two monomers

Role of Enzymes in Reactions

the reactions are mediated by enzymes, which are macromolecules that speed up reactions

Monomer of Carbohydrates

Monosaccharides (sugar monomers)

Monosaccharides

monomer for carbohydrates

used for fuel of cell and organic building blocks ex: glucose, fructose, lactose

generally has a formula that is a multiple of CH2O and contains hydroxyl groups and carbonyl groups

Disaccharides

two monosaccharides bond to form a disaccharide in a dehydration reaction

used as a source of energy (short term) ex: maltose, sucrose

Polysaccharides

long chains of sugar units linked together by dehydration reactions

ex: starch (plants) and glucose (animals) are storage polysaccharides, cellulose (in plant cell walls, structural, chitin (insect/crustacean exoskeleton and fungal cell wall)

Lipids

diverse hydrophobic compounds, composed largely of carbon and hydrogen, three types: fats, phospholipids, steroids

Fats (type of lipid)

consists of glycerol linked to 3 fatty acids: unsaturated fatty acids, saturated fatty acids, trans fats

stores energy (longterm)

Unsaturated Fatty Acids

contains one or more double bonds

typical of plant oils

liquid at room temp

Saturated Fatty Acids

max # of hydrogens

found in animals fats, solid at room temp

Trans Fats

unsaturated fats that turned into saturated fats by adding hydrogen

form of fats associated with health risks

Phospholipids

contains two fatty acids, glycerol and a phosphate group

components of cell membranes

Steroids

lipids made of four fused rings; include cholesterol (in animal cell membranes makes other steroids like sex hormones) and some hormones

Monomer of Proteins

Amino Acids

Chemical Structure of Proteins

differing arrangements of a common set of just 20 amino acid monomers

Importance of Proteins to cells

Functions as:

enzymes

storage proteins

structural proteins (collagen)

signal proteins (hormones)

Denaturation

protein unravels, loses its specific shape, and loses its function

Peptide Bond

links together amino acid monomers in a dehydration reaction

Dipeptide

short chain of two amino acids linked together by a peptide bond

Polypeptide

chain of amino acids linked together by peptide bonds

Four levels of Structure of a Protein

1. Primary structure- sequence of amino acids in its polypeptide chain

2. Secondary structure- coiling or folding of the chain, stabilized by hydrogen bonds

3. Tertiary structure- overall three-dimensional shape of a polypeptide, resulting from interactions among R groups

4. Quaternary structure- made of more than one polypeptide

Polynucleotide

polymer of nucleic acids, built from the monomer nucleotides

Monomer for Nucleic Acids

Nucleotide

Components of a Nucleotide

1. 5 carbon sugar

2. phosphate group

3. nitrogenous base

Compare and contrast DNA and RNA

DNA- double helix of two polynucleotides, contains sugar deoxyribose and four different nitrogenous bases (ATCG), molecule of inheritance

RNA- single polynucleotide chain, contains sugar ribose and four different nitrogenous bases (AUCG), assembles polypeptides according to DNA instructions

Both serve as blueprints for proteins and thus control the life of a cell