Macromolecules Goal Know the structure and function of all 4 macromolecules

Macromolecules : The Molecules of Life Within cells, small organic molecules called monomers are joined together to form larger molecules, known as Macromolecules. Each cell has thousands of different kinds of macromolecules. Macromolecules vary among cells of an organism, vary more within a species, and vary even more between species.

Function: What do macromolecules do? Carbohydrates - short term energy storage; structure of some organisms Lipids - (also known as fats) - long term energy storage Nucleic Acids (DNA and RNA) - the instructions the cell uses to build proteins Proteins (Polypeptides): The highly variable macromolecules that make each organism unique

Carbohydrates Sugars & Starches Used for energy in all organisms and for structure in plants.

Sugars Function: Monosaccharides serve as a major fuel for cells and as raw material for building molecules Monosaccharides have molecular formulas that are usually multiples of CH 2 O – 1:2:1 ratio Glucose is the most common monosaccharide Structure: though often drawn as a linear skeleton, in aqueous solutions they form rings

LE 5-4 Linear and ring forms Abbreviated ring structure

Monosaccharides (simple sugars)= monomer of carbohydrates Mono- = one Glucose (C 6 H 12 O 6 ) = sugar used as an energy source in all cells. Other Examples: Fructose (Fruit sugar) & Galactose (Milk sugar)

Disaccharides (sugars) = 2 monosaccharides linked together. Di- = two Examples: Lactose (milk sugar) & Sucrose (table sugar)

Storage and Structure Polysaccharides 3 or more monosaccharides linked. Poly- = Many Glycogen = Used as energy storage in animals. Cellulose = Used to form the cell wall of plants. Chitin- is found in the exoskeleton of arthropods and the cell walls of many fungi

Storage Polysaccharides Starch, a storage polysaccharide of plants, consists entirely of glucose monomers Plants store surplus starch as granules within chloroplasts and other plastids

LE 5-6a ChloroplastStarch 1 µm Amylose Starch: a plant polysaccharide Amylopectin

LE 5-8 Cellulose molecules Cellulose microfibrils in a plant cell wall Cell walls Microfibril Plant cells 0.5 µm  Glucose monomer

Enzymes that digest starch by hydrolyzing alpha linkages can’t hydrolyze beta linkages in cellulose Cellulose in human food passes through the digestive tract as insoluble fiber Some microbes use enzymes to digest cellulose Many herbivores, from cows to termites, have symbiotic relationships with these microbes

Lipids (fats) Used for long-term energy storage. Steriods

Lipids are a diverse group of hydrophobic molecules Lipids are the one class of large biological molecules that do not form polymers The unifying feature of lipids is having little or no affinity for water Lipids are hydrophobic because  they consist mostly of hydrocarbons, which form nonpolar covalent bonds The most biologically important lipids are fats, sterols and phospholipids.

When phospholipids are added to water, they self- assemble into a bilayer, with the hydrophobic tails pointing toward the interior The structure of phospholipids results in a bilayer arrangement found in cell membranes Phospholipids are the major component of all cell membranes

LE 5-14 WATER Hydrophilic head Hydrophobic tails WATER

Steroids Considered lipids because they are hydrophobic!! Consist of 4 fused rings Cholesterol is a steroid

Nucleic Acids DNA – your genetic code RNA – used to make proteins

Nucleotide = monomer of nucleic acids. Nucleotide has 3 parts: - phosphate - 5-carbon sugar - nitrogen base.

DNA & RNA = Polymers of nucleic acids DNA – di=2 (α-helix) carries the information on how to make proteins. Mostly 2 strands. (1-strand DNA (ssDNA) found in viruses) RNA is directly involved in making proteins. Mostly 1 strand. (2- strand RNA (dsRNA) found in viruses )

Proteins The major building block in living things. Muscles, enzymes, antibodies, cell structure

Proteins have many structures, resulting in a wide range of functions Proteins account for more than 50% of the dry mass of most cells Protein functions include enzymes*,structural support, storage, transport, cellular communications, movement, and defense against foreign substances Different functions=different shapes

Structure of Proteins Protein = Polypeptide (polymer) comprised of monomers (amino acids). There are 20 different amino acids. Amine Group (NH2)-Basic Carboxylic Acid Group (COOH) – Acidic The center asymmetrical carbon is called the alpha carbon. The R group (think random) is variable for each amino acid! Also called the side chain.

Four Levels of Protein Structure Primary structure of a protein is its unique sequence of amino acids. Secondary structure, found in most proteins, consists of coils and folds in the polypeptide chain. The sequence of amino acids converts into 1 of 2 forms »α-helix »β-pleated sheets

1’ and 2’ Levels Protein Structure

Tertiary structure is determined by interactions among various side chains (R groups) Quaternary structure results when a protein consists of multiple polypeptide chains Not found in all proteins Same bonds/interactions as tertiary level

Tertiary & Quaternary Levels

Protein Denaturation

Denaturation Protein unravels and loses its native conformation Structure & Function Change in the protein’s structure = loss of function Denaturation occurs: –Organic solvent –Any chemical that disrupts the tertiary structure –Heat (excessive)

REVIEWREVIEW

MacromoleculeFunctionStructure Carbohydrate Lipid Nucleic Acids Proteins Macromolecules

Sample MC Which molecule stores the largest amount of energy? A. Fat B. Starch C. Protein D. Glycogen

Sample Question A molecule with the chemical formula C 16 H 32 O 16 is probably a A) carbohydrate. B) lipid. C) protein. D) nucleic acid. E) hydrocarbon.

Sample MC Amino acids are the building blocks of A.Proteins B.Lipids C.Carbohydrates D.Nucleic Acids

Sample MC Which polymer carries genetic information? A.Protein B.Lipid C.Carbohydrate D.Nucleic Acid

Unlike carbohydrates and fats, proteins contain _____. A) nitrogen B) carbon C) hydrogen D) oxygen Sample MC

. Which of these elements is NOT part of a carbohydrate molecule? A) hydrogen B) oxygen C) carbon D) magnesium Sample MC

54 oThe rates of reaction among atoms and molecules depends on many factors. We will review the effects of temperature, concentration, and pH, and the presence or absence of catalysts SC.L Reaction Rates & Enzymes

55 What Determines the Speed of a Reaction? Speed of reaction, or “reaction rate” depends on how many collisions occur between reactants. The more collisions, the faster the reaction occurs.

56 Activation Energy The greater the required activation energy of a reaction, the slower the reaction will proceed. If the required activation energy is lowered, a reaction will proceed faster.

Some Chemical Reactions are VERY FAST Reaction between chlorine, Cl 2 (green gas) and sodium metal, produces NaCl, salt

58 Some Chemical Reactions Are VERY Slow This piece of metal has been reacting with oxygen in the air (rusting) for many years. This is a VERY slow reaction which will keep on going for a long time. Where would rust occur more quickly Florida or Arizona?

What are some factors that affect reaction rates? Temperature: more collisions means faster reaction rate Concentration: more reactants means faster reaction rate pH and solubility Optimal pH means faster rate of reaction Catalyst: lower activation energy means faster reaction rate

60 Temperature Particles are Always Moving Atoms of a solidAtoms of a gas in a container

How fast the particles are moving is measured by Temperature Longer arrows show that at a higher temperature the particles are moving faster. Shorter arrows show that at a lower temperature the particles are moving slower.

62 Speed of reaction, or “reaction rate” depends on how many collisions occur between reactants. The more collisions, the faster the reaction occurs The rearranging of the atoms happen ONLY after they collide against each other. Collision theory

63 Temperature The higher the temperature, the more motion in the particles. This means there will be more collisions, and therefore, the reaction rate will be faster. However, prolonged temperature will result in denaturing the enzyme.

64 Concentration Two Containers Filled with CH 4 And O 2 The container above has 40 particles of O 2 and 5 particles of CH 4. What can you say about the rate of reaction in these two containers? The container above has 40 particles of O 2 but 20 particles of CH 4.

65 Concentration of the Reactants The container with more reactants will react faster. More reactants means more collisions and faster reaction rate. Because the second container has more CH 4, we can say it has a higher concentration of CH 4.

66 Effect of Concentration of Oxygen When heated, steel wool reacts with oxygen in the air. The concentration of oxygen in the air is 21%. If the same steel wool is placed in a flask containing 100% oxygen, the reaction occurs much faster.

67 pH (Concentration of H+) pH is a measure of the Hydrogen Ion (H+) concentration in a solution. The rate of certain reactions is affected by the pH of the solution. Most enzymes (which are catalyst) have an optimum pH of between 4 and 9, and quite frequently near the neutral point of 7. The activity of enzymes is strongly affected by changes in pH and temperature.

68 Catalysts A catalyst is a substance that makes a reaction go faster by lowering the required activation energy. A catalyst IS NOT changed or used up in a reaction.

69 Biological Catalysts - Enzymes Living organisms also have catalysts that speed up reactions. These catalysts are called enzymes. Enzymes in the blood catalyze the decomposition of hydrogen peroxide. That is why applying hydrogen peroxide on a wound makes it foamy.

70 The blue line represents a reaction without a catalyst. The red line represents a reaction where a catalyst was added. The activation energy is lower so the reaction will go faster. Effect of a Catalyst

1. Which of the following is a way to slow a reaction? A placing the reactants under bright light B placing the reactants in a tightly sealed container C filtering out some of the reactants D moving the reaction to a warmer room

2. In the collision theory to explain chemical reactions, what must happen for a reaction to take place? A Reactants must collide with the surface of the container B Reactants must collide and have the same energy C Reactants must collide and have enough energy to react D Reactants must collide and have very little energy

3.A carbohydrate is an organic compound that is composed of carbon, hydrogen, and oxygen. The unique structure of carbohydrates makes them useful material for building cell walls in plants. Which of the following is a function of carbohydrates in animals? A.digesting food B.fighting disease C.storing long-term energy D.providing skeletal structure

74 a.It prevents inhibitors form slowing down the reaction among particles. b.It acts as a catalyst to make reactions among particles occur more frequently. c.It causes particles to break apart, which makes it easier for chemical reactions to occur. d.It increases the number of particles that have enough kinetic energy to react when they collide. 4. Raising the temperature usually speeds up the rate of a chemical reaction. Which statement below explains how increasing temperature increases the reaction rate?

5.Metabolism is generally referred to as the chemical processes that allow the body to function. Which of the following molecules allow a metabolic chemical reaction to proceed more quickly? A.Buffers B.Carbohydrates C.Enzymes D.vitamins