Biology PT 2

• Organic compounds of biomolecules are carbohydrates, proteins lipids, nucleic acids
• Monomer a single unit of a polymer
• Polymer are chains of small molecular subunits (building blocks)
• Dehydration Synthesis is a process by which molecules are covalently bonded to each other through a loss of water molecule, facilitated by enzymes
• Hydrolysis process in which bonds between the monomers are broken down by the addition of water molecules.
• sucrose -- glucose + fructose
• lactose -- galactose + glucose
• cellulose -- glucose + glucose
• maltose -- glucose + glucose
• carbohydrates - building block monomer; monosaccharide
• functions of carbohydrates

  Quick energy source ❖ Energy Reserve ❖ Structural Component of Cell ❖ Membrane Receptors
• monosaccharide are simple monomeric sugars, forms the basic subunits of more complex sugars.

  glucose – blood sugar

  fructose – fruit sugar, sweetest

  galactose – milk sugar
• Disaccharide

  two sugar subunits joined together

  maltose (glucose + glucose) – malt sugar

  sucrose (glucose + fructose) – brown/table sugar, refined sugar lactose (glucose + galactose) – milk sugar
• Polysaccharide - many sugar subunits joined together in a long chain or polymer (are typically insoluble in water due to their size)

  glycogen (glucose storage in animals), muscles

  starch (glucose storage in plants)

  cellulose (component of plant cell wall)

  chitin – exoskeleton of arthropods
• PROTEINS - building block (monomer) : Amino Acid 


  • Most abundant and diverse molecules found in living cells

  • Macromolecules, ranging from simply large to enormous

  • Make up about half the total weight of biomolecules in a cell (excluding water)
• Storage Protein - 


  ○ Ovalbumin (storage protein found in egg white)

  ○ Casein (storage protein found in breast milk)

  ○ Ferritin (stores iron)
• Structural materials

  ○ Keratin, the protein found in hair and nails

  ○ Collagen, the protein found in connective tissue
• ❖ Specific Carrier

  ○ Hemoglobin (red blood cell), carry oxygen, iron, and other substances through the body.

  ○ Protein channel (e.g. Sodium-potassium pump)
• Contraction

  ○ Actin and myosin fibers that interact in muscle tissue.
• Signaling

  ○ Hormones such as insulin and glucagon that regulate sugar levels in blood
• Catalyst

  ○ Enzymes accelerate specific chemical reactions

  ○ Trypsin - digestion of proteins in the digestive system
• Components of Enzymes:

  ○ Active Site - where specific molecules bind to the enzyme and the reaction occurs

  ○ Substrate - molecule it reacts with.
• Enzymes and Temperature:

  ○ At low temperatures, enzyme reactions are slow.

  ○ They speed up as the temperature rises until an optimum temperature is reached.

  ○ After this point the reaction will slow down and eventually stop.
• Enzymes and pH

  ○ Most enzymes work fastest in neutral conditions. Making the solution more acidic or alkaline will slow the reaction down. At extremes of pH the reaction will stop altogether.

  ○ Some enzymes, such as those used in digestion, are adapted to work faster in unusual pH conditions and may have an optimum pH of 2 (very acidic) if they act in the stomach.

  ○ pH 1-6 (acidic), pH 7 (neutral), pH above 7 (basic)
• Enzymes and Substrate Concentration

  ○ Enzymes will work best if there is plenty of substrate available.

  ○ As the concentration of the substrate increases, so does the enzyme activity.

  ○ However, the enzyme activity does not increase without end. This is because the enzyme can't work any faster even though there is plenty of substrate available.
• Lipids - - building block (monomer): Fatty Acids

  • Include various biomolecules whose common property is their insolubility in water

  • Unlike other classes of biomolecules, lipids do not form large polymers
• Functions:

  ❖ Contributing to the structure of membranes that enclose cells and cell compartments

  ❖ Protecting against desiccation

  ❖ Storing concentrated energy

  ❖ Insulating against cold

  ❖ Absorbing shocks

  ❖ Regulating cell activities by hormone actions
• Types of Fats:

  • Composed of three fatty acids and glycerol (triglycerides)

  • Solid or liquid at room temperature.

  • Fatty acids can be saturated or unsaturated.
• Saturated Fatty Acids

  ○ If each carbon is joined to its neighboring carbons by a single bond ○ Solid at room temperature

  ○ Raise LDL (low-density lipoprotein) cholesterol levels in the blood. This increases the chances for developing cardiovascular disease (atherosclerosis, cerebral membrane, hemorrhage)

  ○ Bad Cholesterol
• Unsaturated Fatty Acids

  ○ Lower LDL levels and reduce the risk for disease

  ○ Double bond (=)

  ○ Liquid at room temperature

  ○ Good Cholesterol
• Monounsaturated fat: avocado, nuts, and vegetable oils, such as canola, olive, and peanut oils. Monounsaturated fats may also keep "good" HDL cholesterol levels high.
• Polyunsaturated fat: vegetable oils such as safflower, sunflower, sesame, soybean, and corn oils. Polyunsaturated fat is also the main fat found in seafood.
• Omega-3 fatty acids: plants like canola oil, walnuts, and flaxseed. They are also found in fatty fish and shellfish as Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Salmon, anchovies, herring, sardines, Pacific oysters, trout, Atlantic mackerel, and Pacific mackerel are high in EPA and DHA and lower in mercury.
• Omega-6 fatty acids are found mostly in liquid vegetable oils like soybean oil, corn oil, and safflower oil
• Trans-Unsaturated Fatty Acids

  ○ Uncommon in natural fatty acids

  ○ Form readily when polyunsaturated fatty acids from plants are "partially hydrogenated" chemically. This is done commercially to make plant fatty acids more solid and to improve self-life.

  ○ Epidemiological studies correlate consumption of trans fatty acids with increased risk of heart disease
• Phospholipid

  • Major component of cell membranes, which enclose and protect the cytoplasm and other contents of a cell

  • Major component of myelin, a fatty substance that is important for insulating nerves and speeding up electrical impulses in the brain
• Steroids

  • Include cholesterol, sex hormones

  • (progesterone, estrogen, and testosterone – responsible for energy) produced by gonads and cortisone
• Waxes

  • Many plants have leaves and fruits with wax coatings to help prevent water loss

  • Some animals also have wax-coated fur or feathers to repel water

  • Unlike most waxes, ear wax is composed of phospholipids and esters of cholesterol
• NUCLEIC ACIDS - building block (monomer): nucleotide

  • Got its name from the cellular location these molecules are found - nucleus
• Function

  ❖ Store and transmit genetic information

  ❖ Protein synthesis