Chemistry of Life

1. Chemistry of Life

2. Nature of matter • Matter: Anything that occupies space & has mass. • Everything in the universe is made of mass. • Atom is the smallest unit of matter that cannot be broken down by chemical means. • Atoms typically have 1 electron for each proton, so they are neutral (no electrical charge)

3. 3 Basic Particles of An Atom: • Particle Charge Location • 1. Proton Positive (+) Nucleus • 2. Neutron neutral (0) Nucleus • 3. Electron Negative (-) Electron Cloud

4. The electrons are located in energy levels located outside of the nucleus where the electrons can move (electron cloud). • LevelElectrons possible in eachlevel • 1 2e- • 2 8e- • 3 18e-

5. Element is a substance made of only 1 kind of atom, and it is a pure substance. • Four elements that make up 96% of the human body: • 1. Carbon • 2. Hydrogen • 3. Oxygen • 4. Nitrogen

6. Atoms can bond together: • A compound is formed when outer electrons are attracted, shared, or transferred from one atom to another atom in order to fill the outer electron levels. • Ex: Na+ + Cl- → NaCl (table salt) =

7. A force that joins atoms is called a bond. • There are 2 types of bonds: • 1. Covalent bonds • 2. Ionic bonds • Ionic and covalent compounds are alike in that they both fill outer electron levels.

8. 1. Covalent Bonds are created when 2 or more atoms share electrons and form a molecule. • Molecules are held together by covalent bonds. • Example: H2O, CO2, and O2 • All organic compounds are held together by covalent bonds. • Molecules with an unequal distribution of electrical charge, such as water molecules, are polar molecules.

9. Water has a positive charge on one end and a negative charge on the other. Because of its uneven charge, water is a polar molecule. • A hydrogen bond is a weak chemical attraction between polar molecules.

10. 2. Ionic Bonds are formed by the electrical attraction between oppositely charged ions. • Ion is a charged atom or molecule. • Ions have an elec- trical charge because they contain an un- equal number of elec- trons and protons.

11. Ionic Bonds Cont. • An atom that has lost electrons is positively charged. • An atom that has gained electrons is negatively charged. • Ions or opposite charges may interact to form an ionic bond. • Example of an ionic bond: Na+ + Cl- = NaCl

12. Water and Solutions • Water is an inorganic substance which means it is not made from carbon or living things. • Water is composed of 1 atom of oxygen and 2 atoms of hydrogen. • Water molecules are linked by hydrogen bonds. • This causes water to heat up and cool down slowly. • Water, which is essential for life, stores heat efficiently and binds to itself and other sub- stances. • The most abundant inorganic substance in a cell is water.

13. The hydrogen bonds between water molecules cause the cohesion of liquid water. Cohesion is an attraction between substances of the same kind. Because of cohesion, water and other liquids form drops and thin films. The thin films allow some insects to stand on the surface of water because water is cohesive and adhesive. This attraction between water molecules (to itself) causes a condition known as surface tension.

14. Water molecules are also attracted to many other polar substances. • Adhesion is an attraction between different substances. Because water stick to solids (adhesion), water has the property of capillarity. • Capillarity is the ability to spread through fine pores or to move upward through tubes (such as the stem of a plant) against the force of gravity. The attraction of water to the walls of the tube sucks the water up more strongly than gravity pulls it down.

15. Water dissolves many substances: • Due to water’s polar nature (uneven charge), water makes a good solvent, pulling apart other molecules. Nonpolar molecules do not dissolve well in water. When nonpolar substances, such as oil are placed in water, the oil forms lumps or beads in water. Nonpolar molecule and water Polar Molecules and water

16. High Specific Heat • The ability of water to stabilize temperature depends on its relatively high specific heat. • The specific heat of a substance is defined as the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature 1 C. • The specific heat of water is 1.00 cal/g C. • Compared with most other substances, water has an unusually high specific heat. • Because of high specific heat, water will change its temperature less when it absorbs or loses a given amount of heat.

17. Acids and Bases: • pH is a measure of how acidic or basic (alkaline) a solution is. A change of one pH unit reflects a 10X change. • The pH scale ranges from 0-14 and is used to measure pH. • An acid is any substance that forms hydrogen ions (H+) in water. • This solution contains more H+ (hydrogen) ions and has a pH<7 • Sour and corrosive • Tend to burn • Turn litmus paper red • Examples: battery acid, sulfuric acid, stomach acid

18. Acids and Bases • A base (alkaline) is any • substance that forms OH- (hydroxide) ions and has a pH>7 • Are bitter and feel slippery • Turn litmus paper blue • Examples: soaps, household cleaners • A pH of 7indicates a neutral between acidic and alkalinity.

20. Chemistry of cells • Organic compounds contain carbon atoms that are covalently bonded to other elements, typically hydrogen, oxygen and other carbon atoms. • All organic compounds contain the element carbon. • Carbon is the essential element that all life depends on. • Carbon can form up to 4 covalent bonds with other molecules. • Its nature allows the ability to form straight chains, branched chains, and rings. • Carbon’s ability to form covalent bonds is important in allowing for a wider variety of organic molecules. Living things require such a variety to carry out life processes.

21. Four Classes of Organic Compounds Found in Living Things: • 1. Carbohydrates • 2. Lipids • 3. nucleic acids • 4. proteins • Without these compounds cells could not function. • All of these compounds are long repeating units called polymers. • Polymers are large molecules formed when many smaller molecules bond together usually in long chains. • Each unit of a polymer is called a monomer (simple molecule).

22. Polymer Monomer

23. 1. Carbohydrates are organic compounds made of carbon, hydrogen, and oxygen atoms in 1:2:1 ratio. • All carbohydrates are made of carbon, hydrogen, and oxygen. • They are the main source of energy for living things, and they are found in most foods—like fruits, vegetables, and grains. Most energy that is used in the human body is stored as carbohydrates. =

24. There are 3 types of carbohydrates: 1. Monsaccharides or simple sugars. They are the building blocks of carbohydrates. • Examples of monosaccharides: • 1. Glucose is manufactured by plants during photosynthesis. It is the main source of energy for plants and animals. • 2. Fructose is found in fruits and is sweet. These have the same molecular formulas, C6H12O6, but different structural formulas, which make them isomers.

25. Carbohydrates Cont. 2. Disaccharides are 2 monosaccharide molecules linked. • Example of a disaccharide is sucrose (table sugar), which is composed of fructose and glucose. Lactose that is found in milk is an example of a disaccharide. =

26. Carbohydrates Cont. • 3. Polysaccharides are composed of many monosaccharide subunits. Polysaccharides function as storehouses of the energy contained sugars. • Three examples of polysaccharides that store energy: • 1. Starch which is made by plants (like potatoes). Energy is passed from potato to the person eating it primarily by the energy stored in starch molecules. • 2. Glycogen which is made by animals. Both starch and glycogen are made of hundreds of linked glucose molecules. • 3. Cellulose is a polysaccharide that provides structural support for plants. Humans cannot digest cellulose (wood). Starch Glycogen in Liver Cells Cellulose

27. Lipids are non polar molecules that are not soluble in water. • Lipids are used to store energy (long term storage), for insulation, and as protective coatings. • Lipids are composed of 3 fatty acids bonded to a glycerol molecule. • Examples of lipids: fats, phospholipids, steroids, including cholesterol, and waxes. Fats Cholesterol Waxes Steroids

28. Lipids Cont. • The monomers of lipids are fatty acids • Lipids are an important part of the structure and functioning of cell membranes. • Phospholipids make up the lipid bilayer of cell membranes. • Fats are lipids that store energy. • Saturated Fats are solid at room temperature, and they usually come from animals: butter • Unsaturated Fats are liquid at room temperature, and they usually com from plants like core peanut, and olive. Phospholipid Bilayer

29. Lipids Cont. • Waxes are highly waterproof. • In plants, wax forms a protective coating on the outer surfaces, for example on the leaves. • In animals, wax forms protective layers, for example ear wax.

30. 3. Nucleic Acids are in all of your cells. • The building blocks of nucleic acids are nucleotides. • A nucleic acid is a long chain of smaller molecules called nucleotides. • A nucleotide has three parts; • 1. a sugar • 2. a base • 3. a phosphate group Sugar Phosphate Group Base

31. There are two types of nucleic acids: 1. DNA Deoxyribonucleic Acid • DNA consists of 2 strands of nucleotides that spiral around each other. DNA is a molecule shaped like a spiral staircase also known as a double helix. The 2 strands of a DNA molecule are held together by hydrogen bonds between two bases across from one another. Your chromosomes consist of very long strands of DNA, which stores heredity information (or genetic code) that can be use d to make proteins. 2. RNA Ribonucleic Acid • RNA consists or a single strand of nucleotides RNA DNA

32. 4. Proteins are a chain of molecules called amino acids linked together like parts on a necklace. • Proteins are made of long chains of amino acids. • Amino acids are the building blocks of proteins. • There are 20 different amino acids, which bond to each other by peptide bonds (covalent bonds formed between amino acids). • Some proteins called enzymes regulate chemical reactions in the body but remain unchanged by the reaction. • The complete hydrolysis of a protein would result in the formation of amino acids. Hydrolysis is a chemical reaction in which water is used to break down a compound.

33. Proteins Cont. • ATP-Adenosine Triphosphate • ATP carries energy in cells. • ATP is a single nucleotide with 2 extra energy-storing phosphate groups.

34. Energy and Chemical reactions • Energy is the ability to move or change matter. • A chemical reaction is a process during which chemical bonds between atoms are broken and new ones are formed, producing one or more different substances. • Reactants Products (starting materials)(forms) (newly formed substances)

35. Activation Energy the energy needed to start a chemical reaction. • Enzymes Help Biochemical reactions occur: • Enzymes (proteins) are substances that increase the speed of chemical reactions. • Enzymes are proteins which are substances that reduce the activation energy of a chemical reaction. • A substance on which an enzyme acts during chemical reaction is called a substrate. • Each enzyme is specific and only acts on a particular substance called substrate. An enzyme has deep folds on its surface, and these fold form pockets called active sites. Activation Energy= Energy needed to start a reaction

36. Factors that affect enzyme activity; • 1. Temperature • 2. pH • 3. Enzyme Concentration