Biology Chapter 3: Carbs, Lipids & Proteins

Nucleic Acid

DNA and RNA, functions include storing genetic material, making proteins & providing energy

What is the energy stored in C-C bonds used for?

It is harvested in cellular respiration

• Glycerol

a 3C molecule

• Dehydration Synthesis

a chemical reaction where a hydrogen ion is removed from 1 subunit & a hydroxide ion is removed from another subunit, removing water to put together

• Peptide Bond

a covalent bond between the N in 1 protein and the C from the carboxylic group in a separate protein

• Lipids

a diverse group of molecules that contain regions composed almost entirely of hydrogen & carbon, with nonpolar carbon-carbon and C-H bonds, long term concentrated energy storage o The nonpolar regions make lipids insoluble

• Waxes

a lipid composed of fatty acids covalently bonded to long-chain alcohols o Highly saturated & waterproof o Leaf with protective wax coat

• Phospholipids

a lipid consisting of glycerol bonded to 2 fatty acids & 1 phosphate group o Cellular membranes have a double layer of phospholipids

• Polysaccharide

a polymer composed of many monosaccharides • Glucose - the most common monosaccharide

• Glycogen

a polysaccharide that is commonly stored by animals o Stored in the liver & muscles of animals

• Chitin

a polysaccharide that makes up the exoskeletons of crabs, spiders & insects

• Starch

a polysaccharide, used by plants for energy storage o Potato

• Peptide

a relatively short chain of amino acids

• Secondary Structure

a repeated regular structure assumed by a protein chain, held together by H bonds o Helix - the coiled spring-like secondary structure  Keratin o Pleated Sheet - a form in which many protein chains lie side by side with H bonds holding chains together  Silk

• Sugars

a simple carbohydrate molecule, either a monosaccharide or disaccharide, usually end in "ose"

• Cellulose

a structural polysaccharide that makes up cell walls -Most abundant organic compound on Earth -herbivores have evolved a mechanism (bacteria) to digest cellulose -cellulose = undigestible roughage to humans and animals

Cholesterol

an important cell component that is in animal cell membranes (helps keep cell membranes fluid & flexible), the precursor of all other steroids

Why does the sequence of amino acids in a chain matter?

because slight change in amino acid sequence can affect protein's structure & its function

• Disulfide Bonds

bond between 2 cysteines in a protein, usually causes protein to fold

Are phospholipids hydrophobic or hydrophilic?

both, its fatty acid tails are hydrophobic while its PO4 head is hydrophilic

• Hydrolysis

breaks apart a molecule into its original subunits

• Polymers

chains of monomers

• Triglycerides

chemical name of fats & oil, name based on glycerol -3 fatty acids linked to glycerol

• Functional Groups

commonly occurring combinations of atoms

• Steroids

composed of 4 rings of Carbon atoms Ex: -cholesterol -sex hormones

• Carbohydrate Molecules

composed of carbon, hydrogen & oxygen in the ratio 1:2:1 o Starch

• Saturated

containing the maximum amount of H atoms possible, straight Carbon chain made of only single bonds

• Organic

describes molecules that have a carbon backbone bonded to hydrogen atoms

• Fats & Oils

energy-storing molecules, difference in fats & oils lie in their fatty acid subunits

• Unsaturated

has fewer H atoms, double bonds exist between some carbons

Polar or charged amino acids are ____?

hydrophilic

Nonpolar amino acids are ___?

hydrophobic

• Monomers

individual subunits

• Inorganic Molecules

lack carbon or hydrogen atoms o Water o Salt o CO2(g)

• Fatty Acids

long chains of C & H with a carboxyl acid group (-COOH) at one end

• Proteins

molecules composed of chains of amino acids o The human body has about 100,000 different types of protein

Nucleotide

monomer of nucleic acid

• Enzymes

proteins that promote specific chemical reactions

Quaternary Structure

the complex 3D structure of a protein consisting of more than 1 polypeptide chain, only then does a polypeptide become a functional protein

Tertiary Structures

the complex 3D structure of a single peptide chain, held by disulfide bonds between cysteines, "globular", folds determined by interactions of the amino acid functional groups with one another and with their surroundings

What determines the function in carbohydrates?

the molecular structure

• Primary Structure

the sequence of amino acids in a protein

• Amino Acids

the subunit that makes up proteins, structure: a central carbon bonded to a H atom, a nitrogen containing amino group, a carboxylic acid group, and a varying group

What do phospholipids do in water?

they create a barrier

What are the four groups of lipids?

triglycerides, phospholipids, steroids, waxes

• Disaccharide

two linked monosaccharides

• Denatured

when a protein's normal 3D structure is altered while leaving the primary structure intact - many proteins can't return their functional shape after denaturation

• Monosaccharide

1 sugar molecule

What are some of the functions of polysaccharides?

-energy storage ~starch (plants) ~glycogen (animals in liver & muscles) -structure ~cellulose (plants) ~chitin (arthropods & fungi)

What are the functions of fats?

-energy storage -cushion organs -insulates body

What are some functions of proteins?

-enzymes -structure (keratin, collagen) -carriers & transport (hemoglobin, aquaporin) -cell communication ~signals & receptors -defense (antibodies) -movement (actin & myosin) -storage (bean seed proteins)

What are the functions of carbohydrates?

-fast energy -energy storage -raw materials -structural materials