Chapter 2 The Chemistry of Life

2.1 Life Requires… What are humans and other organisms made of? Matter What is matter? Anything that occupies space and has mass. What are examples of matter? Rock, wood, air, metal, animals.

If you take chalk and break it in half. Is it still chalk? What happens if you do this over and over again?

What is the basic unit of matter? The smallest possible particle is called an atom. Atom= atomos= unable to cut.

What are the three subatomic particles that make up atoms? The nucleus is made up of three subatomic particles. Electrons (outside) Protons (inside) Neutrons (inside)

What kind of charge do these have? Protons: Positive electrical charge + Neutrons: No electrical charge 0 Electrons: Negative electrical charge -

What are these?

What is matter made of? Elements Element: A pure substance that can not be broken down into other substances by chemical means. Made of one type of atom. Are often described as the “basic ingredients” of matter.

Which elements are essential for life? Oxygen Carbon Hydrogen Nitrogen Make up 96% of the living matter in our body.

Some elements have alternate forms called isotopes. An element that has the same number of protons but different number of neutrons. Because they have the same number of electrons, all isotopes of an element have the same chemical properties.

Carbon 12 makes up of 99% of carbon. Carbon 13 and Carbon 14 are extremely rare. Carbon 14 is unstable and radioactive. Carbon 14 is a radioactive isotope. Radioactive isotope: The nucleus decays and gives off radiation. Can be used to determine how old fossils are.

What do you get when you mix sodium(Na) and chlorine (Cl)? Sodium chloride (NaCl)= salt!

This is an example of a compound. Is a substance formed by the chemical combination of two or more elements in a definite proportions.

Chemical Bonds Atoms in compounds are held together by various types of chemical bonds. The electrons that are available to form bonds are called valence electrons. Two types of bonds: Ionic Covalent

Ionic Bonds Ionic bond: Formed when one or more electrons are transferred from one atom to another.

Now that chlorine gained an electron it has a – 1 charge. Sodium lost an electron so now its charge is +1. The two atoms are now referred to as ions. Ions: Atoms that have become electrically charged as a result of gaining or losing electrons.

Covalent bond: Forms when two atoms share electrons.

Molecule: Smallest unit of most compounds.

Van der Waals Forces: When molecules are close together, a slight attraction can develop between the oppositely charged regions of nearby molecules.

2.2 Properties of Water Polarity: A polar molecule is when the opposite ends have opposite electric charges.

Properties of Water Hydrogen bonding: The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge.

Properties of Water Have you ever fell asleep before it rains and wake up to go to the bus and see water covering everything?

Properties of Water Cohesion: Water attracted to water. Adhesion: Water attracted to other substances. Objects can float because of waters surface tension Surface tension: The bond between water molecules.

Properties of Water Which will heat faster… an ocean or pool? Heat capacity: The amount of heat energy required to increase its temperature, is relatively high.

Solutions and Suspensions Water is not always pure, it is often found as part of a mixture. Mixture: Material composed of two or more elements or compounds that are physically mixed together, but not chemically combined.

Solutions What happens when you mix salt in water? It dissolves. You just made a solution. Solution: All the components are evenly distributed throughout the solution.

Solvent: the substance that dissolved the other substance and is present in the greater amount. Solute: the substance that is dissolved and is present in a lesser amount. If you take a pack of salt and mix in water… which is the solute and solvent? Solute Salt Solvent Water

Acids, Bases, and pH pH scale: Describes how acidic or basic a solution is. Ranges from 0 (extremely acidic) to 14 (extremely basic) 7 is neutral (pure water) Most living cells are near 7.

Acids, Bases, and pH Hydrogen ions (positive charge) makes things more acidic. Acid: H+ ions added. Base: The removal of H+ ions.

WCU story. Lemonade, Dr. Pepper Acid hot spring story

Buffers: Substances that cause a solution to resist changes in pH. Human blood normally has a pH of 7.4 When bloods pH decrease (drink lemon juice) and becomes more acidic buffers come in and resist the blood to drop any lower and acidic.

2.3 Carbon Compounds Life without carbon would be as unlikely as life without water. Other than water, most molecules of a cell are carbon-based. These “biochemicals” are composed of a carbon backbone of carbon atoms bonded to one another. Atoms of other elements may branch off this carbon backbone.

Organic molecules: Carbon based molecules. Inorganic molecules: Non based carbon molecules. Ex. Water H20, Oxygen 02, and Ammonia NH3

Macromolecules Monomers: Mono= one Small chemical unit that makes up a polymer Polymers: Poly= many Molecules composed of many monomers; makes up macromolecules.

We have 4 macromolecules Carbohydrates Proteins Lipids Nucleic Acids

Imagine you are preparing for a big race or sport event. What does your body need to give you energy? Carbohydrates What should you eat? Pasta

Carbohydrates Made up of carbon, hydrogen, and oxygen. Usually a 1:2:1 ratio. Monomers are sugars. Function: Main source of energy. (glucose) Some plants and animals use carbs for structural purposes. (cellulose)

Carbohydrates is an organic compound made up of sugar molecules. Monosaccharides= one sugar Ex. Glucose Disaccharides= two sugars Ex. Sucrose Polysaccharides: many sugars Ex. Cellulose All carbohydrates end with –ose Ex. Glucose

Lipids Why do you have to shake well before using a bottle of salad dressing? The oil is a lipid and lipids do not mix well with water. Lipids are hydrophobic. When salad dressing bottle sits the oil and vinegar separates.

Lipids Made up of carbon and hydrogen. Are hydrophobic. Hydro=water phobic=fearing Examples are fats, oils, and waxes. Function: Energy storage. Some lipids are important parts of biological membranes and waterproof coverings.

Types of Fats Saturated fat: ( bad fat) Contain the maximum possible number of hydrogen atoms. Solid at room temperature. Ex. Lard, butter. Unsaturated fat: Contains less than the maximum number of hydrogen bonds. Ex. Olive oil, vegetable oil.

Nucleic Acids Made up of hydrogen, oxygen, nitrogen, carbon, and phosphorus. Subunits are called nucleotides. Function: Store and transmit hereditary, or genetic, information. Examples: DNA and RNA.

Proteins Made up of nitrogen, carbon, hydrogen, and oxygen. Monomers are called amino acids. Function: Control rate of reactions and regulate cell processes.

2.4 Chemical Reactions and Enzymes Process that changes, or transforms, one set of chemicals into another. Reactant: Elements or compounds that enter into a chemical reaction. Product: The elements or compounds produced by a chemical reaction.

Energy in Reactions Activation energy: The energy that is needed to start a chemical reaction.

If you order something online, would you want it to be delivered fast or slow? A catalyst is a substance that speeds up a rate of a chemical reaction. They lower the activation energy.

Nature’s Catalyst Enzymes are proteins that act is biological catalysts. Enzymes speed up the chemical reactions that take place in cells. The shape of an enzyme fits the shape of only particular reactant molecules. A specific reactant acted upon by an enzyme is called the substrate. The substrate fits into a particular region of the enzyme called the active site. Once connected the reactions occurs.

Commonly known as lock and key. Temperature, pH, and regulatory molecules can affect the activity of enzymes.