1. Chapter 6 Biology The Chemistry of Life

2. 6.1 Elements Elements are substances that can’t be broken down into simpler substances Elements are substances that can’t be broken down into simpler substances All elements are found on the periodic table All elements are found on the periodic table Approximately 25 elements are essential for life Approximately 25 elements are essential for life Carbon, hydrogen, nitrogen and oxygen comprise about 96% of the human body Carbon, hydrogen, nitrogen and oxygen comprise about 96% of the human body Trace elements- elements that are present in very small amounts in the body Trace elements- elements that are present in very small amounts in the body Plants obtain these by absorbing them through their roots Plants obtain these by absorbing them through their roots Animals absorb them by eating them in their food Animals absorb them by eating them in their food

3. 6.1 Atoms The smallest particle of an element that has the properties of that element is called an atom The smallest particle of an element that has the properties of that element is called an atom All atoms have the same basic structure All atoms have the same basic structure The nucleus is in the center of the atom The nucleus is in the center of the atom Protons are located here and are positively charged Protons are located here and are positively charged Neutrons are located here and are neutral (no charge) Neutrons are located here and are neutral (no charge) The electron shell is surrounding the nucleus The electron shell is surrounding the nucleus Electrons are located here and are negatively charged Electrons are located here and are negatively charged Electrons exist in energy levels Electrons exist in energy levels 1 st energy levels can hold 2 electrons 1 st energy levels can hold 2 electrons 2 nd energy level can hold 8 electrons 2 nd energy level can hold 8 electrons 3 rd energy level can hold 18 electrons 3 rd energy level can hold 18 electrons

4. 6.1 Isotopes Atoms contain the same number of protons and electons Atoms contain the same number of protons and electons Isotopes are atoms of the same element (same # of protons) with different numbers of neutrons Isotopes are atoms of the same element (same # of protons) with different numbers of neutrons Isotopes are named using the mass number Isotopes are named using the mass number The mass number is the sum of the protons and neutrons in the isotope The mass number is the sum of the protons and neutrons in the isotope For example, a carbon isotope with 7 neutrons would be carbon-13 For example, a carbon isotope with 7 neutrons would be carbon-13

5. 6.1 Bonding When 2 or more elements bond, they form a compound When 2 or more elements bond, they form a compound Properties of compounds are different from the properties of individual elements Properties of compounds are different from the properties of individual elements There are 2 types of bonding to form compounds There are 2 types of bonding to form compounds Ionic- based on the attraction of oppositely charged ions Ionic- based on the attraction of oppositely charged ions Covalent- based on the sharing of electrons Covalent- based on the sharing of electrons

6. 6.1 Ionic Bonding Ions form when atoms gain or lose electrons to become stable Ions form when atoms gain or lose electrons to become stable Atoms that gain electrons become negatively charged Atoms that gain electrons become negatively charged Atoms that lose electrons become positively charged Atoms that lose electrons become positively charged Opposite charges attract, so a positively charged ion is attracted to a negatively charged ion and an ionic bond forms Opposite charges attract, so a positively charged ion is attracted to a negatively charged ion and an ionic bond forms

7. 6.1 Covalent Bonding In covalent bonds, the atoms share electrons between them to make them have enough electrons to be stable In covalent bonds, the atoms share electrons between them to make them have enough electrons to be stable A covalently bonded compound is called a molecule A covalently bonded compound is called a molecule Most compounds found in organisms are covalently bonded Most compounds found in organisms are covalently bonded

8. 6.1 Chemical Reactions Chemical reactions occur when elements and/or compounds react to form different elements and/or compounds Chemical reactions occur when elements and/or compounds react to form different elements and/or compounds The same elements are present before and after the reaction, they have just formed different bonds The same elements are present before and after the reaction, they have just formed different bonds The chemical reactions that occur in an organism are called the metabolism The chemical reactions that occur in an organism are called the metabolism The substances that react are called the “reactants” The substances that react are called the “reactants” The new substances that form are called the “products” The new substances that form are called the “products”

9. 6.1 Chemical Equations Chemical equations show what substances react and what is formed in a chemical reaction Chemical equations show what substances react and what is formed in a chemical reaction The reactants are on the left side (2H 2 + O 2 ) The reactants are on the left side (2H 2 + O 2 ) The products are on the right side (2H 2 O) The products are on the right side (2H 2 O) The numbers in front of chemical formulas tell you how many molecules of a substance react or are formed (in yellow) The numbers in front of chemical formulas tell you how many molecules of a substance react or are formed (in yellow) The subscripts, or numbers below the symbols tell you how many of each element are in a compound (in green) The subscripts, or numbers below the symbols tell you how many of each element are in a compound (in green) If there is no subscript, it is assumed to be a “1” If there is no subscript, it is assumed to be a “1” 2H 2 + O 2  2H 2 O

10. 6.1 Mixtures & Solutions Mixtures occur when 2 substances are mixed, but do not react Mixtures occur when 2 substances are mixed, but do not react The substances in a mixture keep their own properties The substances in a mixture keep their own properties This means they can be separated again easily This means they can be separated again easily Solutions are a type of mixture that occurs when 2 substances are mixed and one dissolves in another Solutions are a type of mixture that occurs when 2 substances are mixed and one dissolves in another Living things require solutions such as glucogon, insulin, and dissolved minerals Living things require solutions such as glucogon, insulin, and dissolved minerals

11. 6.1 Acids & Bases pH is a measure used to determine how acidic or basic a substance is pH is a measure used to determine how acidic or basic a substance is pH has a general range between 0 and 14 pH has a general range between 0 and 14 Acids have a pH less than 7 Acids have a pH less than 7 Acids form hydrogen ions (H + ) in water Acids form hydrogen ions (H + ) in water Bases have a pH greater than 7 Bases have a pH greater than 7 Bases form hydroxide ions (OH - ) in water Bases form hydroxide ions (OH - ) in water Neutral substances have a pH of exactly 7 Neutral substances have a pH of exactly 7

12. 6.2 Properties of Water Most organisms are made up of 70-95% water Most organisms are made up of 70-95% water Water has a variety of unique properties Water has a variety of unique properties Water is polar, meaning one end is positive and one end is negative Water is polar, meaning one end is positive and one end is negative This allows water to dissolve many substances This allows water to dissolve many substances This allows water to form very strong bonds with itself, giving it a very high surface tension This allows water to form very strong bonds with itself, giving it a very high surface tension These bonds are called hydrogen bonds These bonds are called hydrogen bonds Water resists changes in temperature Water resists changes in temperature Water expands when it freezes (most liquids get smaller when they freeze) Water expands when it freezes (most liquids get smaller when they freeze)

13. 6.2 Motion All objects in motion have kinetic energy All objects in motion have kinetic energy Individual particles in matter are constantly moving (they individually have kinetic energy) Individual particles in matter are constantly moving (they individually have kinetic energy) This motion causes the particles to collide with one another and bounce off This motion causes the particles to collide with one another and bounce off This creates random motion, known as Brownian motion This creates random motion, known as Brownian motion This motion results in the process of diffusion This motion results in the process of diffusion

14. 6.2 Diffusion Particles in 2 solutions of different concentrations will try to make the concentrations equal using Brownian motion Particles in 2 solutions of different concentrations will try to make the concentrations equal using Brownian motion This process is called diffusion This process is called diffusion It is a slow process and can take hours, days, weeks, or longer depending on several factors It is a slow process and can take hours, days, weeks, or longer depending on several factors Once the concentration has become equal throughout, the particles will continue to move, but not change the concentration Once the concentration has become equal throughout, the particles will continue to move, but not change the concentration This is called dynamic equilibrium This is called dynamic equilibrium

15. 6.2 Factors Affecting Rate of Diffusion There are 3 factors that will affect the rate of diffusion: There are 3 factors that will affect the rate of diffusion: Concentration- the more concentrated the solutions, the more collisions can occur and the faster diffusion takes place Concentration- the more concentrated the solutions, the more collisions can occur and the faster diffusion takes place This factor has the biggest effect This factor has the biggest effect Temperature- increased temperature causes the kinetic energy of the particles to increase, which leads to more collisions, making diffusion occur faster Temperature- increased temperature causes the kinetic energy of the particles to increase, which leads to more collisions, making diffusion occur faster Pressure- increased pressure speeds up the motion of the particles, making diffusion occur faster Pressure- increased pressure speeds up the motion of the particles, making diffusion occur faster

16. 6.2 Diffusion in Living Systems Most substances in organisms, particularly in and around cells, are solutions Most substances in organisms, particularly in and around cells, are solutions Cells use diffusion to move substances, such as vitamins and minerals, into or out of a cell Cells use diffusion to move substances, such as vitamins and minerals, into or out of a cell Diffusion is also the process that transports oxygen into the lungs and removes carbon dioxide from the lungs Diffusion is also the process that transports oxygen into the lungs and removes carbon dioxide from the lungs

17. 6.3 Carbon All organisms contain carbon All organisms contain carbon Carbon can form 4 bonds with itself or other elements Carbon can form 4 bonds with itself or other elements It can form single bonds, which involve the sharing of 2 electrons It can form single bonds, which involve the sharing of 2 electrons It can form double bonds, which involve the sharing of 4 electrons It can form double bonds, which involve the sharing of 4 electrons It can form triple bonds, which involve the sharing of 6 electrons It can form triple bonds, which involve the sharing of 6 electrons

18. 6.4 Carbon Chains Carbon has a tendency to bond to itself and form chains Carbon has a tendency to bond to itself and form chains Carbon can form isomers-compounds with the same formula, but different 3D structures Carbon can form isomers-compounds with the same formula, but different 3D structures Long chains of carbon in organic compounds are called biomolecules Long chains of carbon in organic compounds are called biomolecules Cells build biomolecules by bonding smaller molecules together to form polymers Cells build biomolecules by bonding smaller molecules together to form polymers

19. 6.4 Carbohydrates Carbohydrates are biomolecules containing carbon, hydrogen, and oxygen Carbohydrates are biomolecules containing carbon, hydrogen, and oxygen These usually have 2 hydrogen atoms and 1 oxygen atom for every carbon atom These usually have 2 hydrogen atoms and 1 oxygen atom for every carbon atom There are 3 types of carbohydrates There are 3 types of carbohydrates Monosaccharides-contain one sugar molecule Monosaccharides-contain one sugar molecule Examples are glucose and fructose Examples are glucose and fructose Disaccharides-contain 2 sugar molecules Disaccharides-contain 2 sugar molecules An example is sucrose (glucose plus fructose) An example is sucrose (glucose plus fructose) Polysaccharides- contain many sugar molecules Polysaccharides- contain many sugar molecules Examples include starch, cellulose, and glycogen Examples include starch, cellulose, and glycogen

20. 6.4 Lipids Lipids are biomolecules containing carbon and hydrogen with very small amounts of oxygen Lipids are biomolecules containing carbon and hydrogen with very small amounts of oxygen They include fats, oils, waxes, and steroids They include fats, oils, waxes, and steroids They do not dissolve in water They do not dissolve in water Lipids are classified into 3 types: Lipids are classified into 3 types: Saturated-containing only single C-C bonds Saturated-containing only single C-C bonds Unsaturated- contains at least 1 double or triple C-C bond Unsaturated- contains at least 1 double or triple C-C bond Polyunsaturated- contains more than one double or triple C-C bond Polyunsaturated- contains more than one double or triple C-C bond

21. 6.4 Proteins Proteins are large polymers made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur Proteins are large polymers made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur They are required for life to exist They are required for life to exist They provide structure for tissues and organs and carry out cell metabolism They provide structure for tissues and organs and carry out cell metabolism Proteins are made up of amino acids Proteins are made up of amino acids There are 20 common amino acids that bond to create proteins There are 20 common amino acids that bond to create proteins The bonds that form are called peptide bonds and occur when one amino acid gives up a hydrogen atom and another gives up a hydrogen and an oxygen atom, which form water in addition to the protein The bonds that form are called peptide bonds and occur when one amino acid gives up a hydrogen atom and another gives up a hydrogen and an oxygen atom, which form water in addition to the protein

22. 6.4 Protein Properties Properties of proteins are determined by the order in which the amino acids bond, the specific amino acids that are present, and the number of amino acids that bond Properties of proteins are determined by the order in which the amino acids bond, the specific amino acids that are present, and the number of amino acids that bond Enzymes are a specific type of protein that changes the rate of a chemical reaction Enzymes are a specific type of protein that changes the rate of a chemical reaction They effect nearly all metabolic processes They effect nearly all metabolic processes An example is digestion An example is digestion They are affected by the temperature, the ionic conditions, and the pH of the reaction medium They are affected by the temperature, the ionic conditions, and the pH of the reaction medium

23. 6.4 Nucleic Acids Nucleic acids are biomolecules that store cellular information in code Nucleic acids are biomolecules that store cellular information in code They are polymers made up of nucleotides They are polymers made up of nucleotides They are made up of 3 components: They are made up of 3 components: PhosphateSugarNitrogenous Base Examples include DNA and RNA Examples include DNA and RNA