Chemistry of Life Life Science Book pp.66-73

The Importance of Food Living things need food for building tissue and for energy. What is not used is eliminated from the body as waste. Living things need food for building tissue and for energy. What is not used is eliminated from the body as waste. Example: Muscle Tissue Example: Muscle Tissue

What Substances Make Up Food? Sugars Sugars Vitamins Vitamins Minerals Minerals Proteins Proteins Water Water Waste Waste

What happens when food is eaten? The substances in food break apart from one another. The substances in food break apart from one another. First the teeth and tongue break the food into smaller pieces manually. First the teeth and tongue break the food into smaller pieces manually. Second, chemicals such as enzymes and acids break the food down chemically into small molecules. Second, chemicals such as enzymes and acids break the food down chemically into small molecules.

What are molecules? Molecules are two or more atoms chemically bonded to each other. Molecules are two or more atoms chemically bonded to each other.

What is an atom? Atoms are the basic building blocks of all substances, both living and non-living. Atoms are the basic building blocks of all substances, both living and non-living. Consists of: Consists of: Nucleus that contains: Nucleus that contains: Positively charged protons Positively charged protons Neutral neutrons Neutral neutrons Electron cloud that contains: Electron cloud that contains: Negatively charged electrons Negatively charged electrons

Elements A substance made up of only one type of element. A substance made up of only one type of element. Can’t be broken down into a simpler form by chemical reactions. Can’t be broken down into a simpler form by chemical reactions. Arranged in a chart known as Periodic Table of Elements. Arranged in a chart known as Periodic Table of Elements.

Elements That Make Up the Human Body SymbolElementPercent OOxygen65.0 CCarbon18.5 HHydrogen9.5 NNitrogen3.2 CaCalcium1.5 PPhosphorous1.0 KPotassium0.4 SSulfur0.3 NaSodium0.2 ClChlorine0.2 MgMagnesium0.1 Other elements0.1

Most Common Elements in Human Body Six elements listed on the table make up 99% of living matter. Six elements listed on the table make up 99% of living matter. Oxygen – O Oxygen – O Carbon – C Carbon – C Hydrogen – H Hydrogen – H Nitrogen – N Nitrogen – N Calcium – Ca Calcium – Ca Phosphorus – P Phosphorus – P

What can we learn about an element from the periodic table? felementsc.pdf felementsc.pdf felementsc.pdf felementsc.pdf Metal or Non-metal Metal or Non-metal State at room temperature State at room temperature Mass of the atom (# protons + # neutrons) Mass of the atom (# protons + # neutrons) Number of protons (= atomic number) Number of protons (= atomic number) Number of electrons (= atomic number) Number of electrons (= atomic number) Number of neutrons ( = atomic mass – # protons) Number of neutrons ( = atomic mass – # protons) And more! And more!

Use the periodic table to learn about Mg Name is magnesium Name is magnesium Atomic mass = 24 amu (atomic mass units) Atomic mass = 24 amu (atomic mass units) Atomic number = 12 Atomic number = 12 Metal Metal In column 2, row 2 – Will have 2 shells and 2 electrons in outer shell In column 2, row 2 – Will have 2 shells and 2 electrons in outer shell Number of protons = 12 Number of protons = 12 Number of electrons = 12 Number of electrons = 12 Number of neutrons = (24 – 12) Number of neutrons = (24 – 12)

What would a model of magnesium look like?

Placement of Electrons Electrons travel in shells around the nucleus of an atom. Electrons travel in shells around the nucleus of an atom. Each shell represents an energy level. The further from the nucleus, the higher the energy level. Each shell represents an energy level. The further from the nucleus, the higher the energy level. Within each shell are orbitals. Each orbital is a different energy level. Electrons fill shells from least energy level to greatest. Sometimes this means putting electrons in the next shell before completely filling the previous shell. Within each shell are orbitals. Each orbital is a different energy level. Electrons fill shells from least energy level to greatest. Sometimes this means putting electrons in the next shell before completely filling the previous shell.

Electron Filling Order Shell / OrbitalMax. Number of Electrons 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10

Examples Potassium K Maximum 1 st shell can hold is 2. Maximum 1 st shell can hold is 2. Maximum 2 nd shell can hold is 8. Maximum 2 nd shell can hold is 8. Maximum 3 rd shell can hold is 18 but only has 8. Maximum 3 rd shell can hold is 18 but only has 8. 1 electron goes into shell 4 because 4s is lower energy than 3d. 1 electron goes into shell 4 because 4s is lower energy than 3d.

Strontium Sr Strontium has 38 electrons Strontium has 38 electrons 1s s s 2 s 2 s 2 s 2 s 2 s 2 2s 2 s 2 s 2 s 2 s 2 s 2 2p 6 p 6 p 6 p 6 2p 6 p 6 p 6 p 6 3s 2 d 10 d 3s 2 d 10 d 3p 6 f 3p 6 f 4s 2 4s 2 3d 10 3d 10 4p 6 4p 6 5s 2 5s 2

Atoms Combine to Form Compounds Definition: A compound is a substance made up of two or more elements in exact proportions. Definition: A compound is a substance made up of two or more elements in exact proportions. Example: H 2 O – water is always made up of 2 atoms of hydrogen bonded to 1 atom of oxygen. Example: H 2 O – water is always made up of 2 atoms of hydrogen bonded to 1 atom of oxygen. Compounds have properties different from the elements they are made of. Compounds have properties different from the elements they are made of.

Two Types of Compounds Molecular (covalent) – compounds form when atoms share electrons. Molecular (covalent) – compounds form when atoms share electrons. Example: Each atom of hydrogen in a water molecule shares 1 atom with the oxygen atom. Example: Each atom of hydrogen in a water molecule shares 1 atom with the oxygen atom. Ionic compounds – form when positively and negatively charged atoms (ions) are attracted to each other. Ionic compounds – form when positively and negatively charged atoms (ions) are attracted to each other. Chlorine gains an electron from sodium and becomes negatively charged: Cl 1- Chlorine gains an electron from sodium and becomes negatively charged: Cl 1- When sodium loses an electron, it has one more proton than electron and has a positive charge: Na 1+ When sodium loses an electron, it has one more proton than electron and has a positive charge: Na 1+ Na 1+ + Cl 1-  NaCl Na 1+ + Cl 1-  NaCl

Important Compounds in Living Things Organic Compounds – Always contain carbon and hydrogen and generally associated with living things: Organic Compounds – Always contain carbon and hydrogen and generally associated with living things: Carbohydrates Carbohydrates Lipids Lipids Proteins Proteins Nucleic Acids Nucleic Acids

Carbohydrates Supply energy for all cell processes Supply energy for all cell processes Contain the elements carbon, oxygen and hydrogen Contain the elements carbon, oxygen and hydrogen Examples: sugars, starches, cellulose Examples: sugars, starches, cellulose

Lipids Store and release even more energy than carbs. Store and release even more energy than carbs. Do not mix with water. Do not mix with water. Made up of carbon, oxygen, hydrogen, and phosphorus Made up of carbon, oxygen, hydrogen, and phosphorus Examples: fats, oils, phospholipids, cholesterol Examples: fats, oils, phospholipids, cholesterol

Proteins Building blocks of many structures, such as muscles, in the body. Building blocks of many structures, such as muscles, in the body. Proteins called enzymes regulate most chemical reactions in cells. Proteins called enzymes regulate most chemical reactions in cells. Made up of small molecules called amino acids. Made up of small molecules called amino acids. Contain the elements carbon, oxygen, hydrogen, nitrogen, and sulfur. Contain the elements carbon, oxygen, hydrogen, nitrogen, and sulfur.

Nucleic Acids Store important information in cells. Store important information in cells. Example: DNA and RNA Example: DNA and RNA Contains the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus Contains the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus

Inorganic Compounds Most are made from elements other than carbon. Most are made from elements other than carbon. Usually smaller than organic compounds. Usually smaller than organic compounds. Examples: Examples: Calcium phosphate – gives strength to bones Calcium phosphate – gives strength to bones Hydrochloric acid – breaks down food in stomach Hydrochloric acid – breaks down food in stomach Sodium bicarbonate – helps digestion occur Sodium bicarbonate – helps digestion occur Salts containing sodium, chlorine and potassium – helps send messages along nerves Salts containing sodium, chlorine and potassium – helps send messages along nerves Water – makes up blood; most chemical reactions occur in water. Water – makes up blood; most chemical reactions occur in water.

Characteristics of Water H end of water molecule has a + charge and O end has a – charge. The (+) end of one water molecule attracts the (-) end of another water molecule. This allows small insects to walk on water. H end of water molecule has a + charge and O end has a – charge. The (+) end of one water molecule attracts the (-) end of another water molecule. This allows small insects to walk on water. When substances are heated, the molecules start to move. Water molecules don’t move as easily because of the attraction noted above; therefore; water temperature does not change quickly. When substances are heated, the molecules start to move. Water molecules don’t move as easily because of the attraction noted above; therefore; water temperature does not change quickly. In living things, water acts as an insulator, helping to keep temperature constant. In living things, water acts as an insulator, helping to keep temperature constant. Ice floats when frozen. This ice protects water animals from extremely low temps. Ice floats when frozen. This ice protects water animals from extremely low temps.

Wrap Up Food is made up of molecules. Food is made up of molecules. We break down these molecules and separate out what we need from what we don’t need. We break down these molecules and separate out what we need from what we don’t need. Some of the molecules are used to rebuild tissue, bones, etc. Some of the molecules are used to rebuild tissue, bones, etc. Some are used as fuel for energy. Some are used as fuel for energy. Water plays an important role as a key ingredient of blood that allows it to break down and transport nutrients throughout the body and to regulate temperature. Water plays an important role as a key ingredient of blood that allows it to break down and transport nutrients throughout the body and to regulate temperature.