1. Biochemistry Textbook Chapter 6 Review Topic 2

2. Basic Chemistry Chemistry – the study of matter (anything with a mass and takes up space) Chemistry – the study of matter (anything with a mass and takes up space) All of the organisms we study are made of matter All of the organisms we study are made of matter

3. Atoms Atoms Building blocks of matter Building blocks of matter Made of protons (+), Made of protons (+), neutrons (0) & electrons (-) Structure contains a nucleus (protons/neutrons) and an energy field (electrons) Structure contains a nucleus (protons/neutrons) and an energy field (electrons) Atoms will contain equal numbers of protons and electrons (so the overall charge is zero) Atoms will contain equal numbers of protons and electrons (so the overall charge is zero)

4. Elements Elements Pure substance that cannot be broken down into other substances (physically or chemically) Pure substance that cannot be broken down into other substances (physically or chemically) Made of ONE type of atom Made of ONE type of atom 100 known elements (92 occur naturally) 100 known elements (92 occur naturally) Each element has a name and a symbol Each element has a name and a symbol Organized in the periodic table of elements Organized in the periodic table of elements

5. Elements continued… Elements continued… Periodic table of elements Periodic table of elements Each element has an assigned symbol, name, atomic number (# protons), atomic mass Each element has an assigned symbol, name, atomic number (# protons), atomic mass (# protons + # neutrons) Organized into horizontal rows (periods) and vertical columns (groups) Organized into horizontal rows (periods) and vertical columns (groups) Each block is a different element Each block is a different element Elements with similar chemical and physical properties are grouped together Elements with similar chemical and physical properties are grouped together

7. Elements continued… Elements continued… Isotopes Isotopes Atoms of the same element with different numbers of neutrons Atoms of the same element with different numbers of neutrons Found by comparing the difference in protons plus neutrons (atomic mass) Found by comparing the difference in protons plus neutrons (atomic mass) Isotopes of an element have the same chemical characteristics but can be less stable (radioactive) Isotopes of an element have the same chemical characteristics but can be less stable (radioactive) Ex. Carbon-12 and Carbon-14 Ex. Carbon-12 and Carbon-14

8. Compounds Compounds Formed when two or Formed when two or more different elements combine (NOT a mixture!) Use chemical formulas showing element symbols and subscripts Use chemical formulas showing element symbols and subscripts Compounds are chemically and physically different from the elements involved Compounds are chemically and physically different from the elements involved Cannot be broken down physically ONLY CHEMICALLY Cannot be broken down physically ONLY CHEMICALLY

9. Chemical Bonds Chemical Bonds Forces which hold the elements in a compound together Forces which hold the elements in a compound together Involves the electrons of an atom Involves the electrons of an atom Shared between two atoms (covalent bond) Shared between two atoms (covalent bond) Transferred between two atoms forming ions with opposite charges (ionic bond) Transferred between two atoms forming ions with opposite charges (ionic bond) Forming bonds stores energy, breaking bonds releases energy Forming bonds stores energy, breaking bonds releases energy Can be single, double or triple Can be single, double or triple

11. Van der Waals Forces Van der Waals Forces Attractive forces between molecules due to their positive and negative regions Attractive forces between molecules due to their positive and negative regions Not as strong as bonds Not as strong as bonds Ex. Geckos Ex. Geckos

12. Chemical Reactions Process where compounds are reorganized to form different compounds Process where compounds are reorganized to form different compounds Bonds are broken and reformed Bonds are broken and reformed Not all changes are chemical reactions Not all changes are chemical reactions Ex. Melting of ice (physical) versus rusting of a car (chemical) Ex. Melting of ice (physical) versus rusting of a car (chemical)

13. Chemical Equations Chemical Equations Reactants are the starting substances Reactants are the starting substances Products are formed Products are formed Arrow represents the reaction that occurred Arrow represents the reaction that occurred Reactants  Products Ex. C 6 H 12 O 6 + O 2  CO 2 + H 2 O Matter is not created or destroyed in a chemical reaction (conservation of mass) Matter is not created or destroyed in a chemical reaction (conservation of mass)

14. Main Ideas Atoms consist of protons, neutrons and electrons Atoms consist of protons, neutrons and electrons Elements are pure substances made up of only one kind of atom Elements are pure substances made up of only one kind of atom Isotopes are forms of the same element that have a different number of neutrons Isotopes are forms of the same element that have a different number of neutrons Compounds are substances with unique properties that are formed when elements combine Compounds are substances with unique properties that are formed when elements combine Elements can form covalent and ionic bonds Elements can form covalent and ionic bonds Chemical reactions cause the rearrangement of atoms into different substances Chemical reactions cause the rearrangement of atoms into different substances

15. Enzymes Most compounds in living things cannot undergo chemical reactions without energy Most compounds in living things cannot undergo chemical reactions without energy The minimum energy needed to start a reactions is called the activation energy The minimum energy needed to start a reactions is called the activation energy If the activation energy is high, reactions occur slower If the activation energy is high, reactions occur slower In nature, a catalyst is used to lower the activation energy of a reaction In nature, a catalyst is used to lower the activation energy of a reaction

17. A catalyst A catalyst Speeds up a reaction Speeds up a reaction Does NOT make more products just makes them faster Does NOT make more products just makes them faster Is not used up in the reaction and can be reused Is not used up in the reaction and can be reused Ex. Enzymes (biological catalysts) Ex. Enzymes (biological catalysts)

18. Enzymes Enzymes Substrate – reactants which bind Substrate – reactants which bind to the enzyme Active site – location where the Active site – location where the substrate binds on the enzyme Only substrates with the same size and shape as the active site will bind to the enzyme (lock & key model) Only substrates with the same size and shape as the active site will bind to the enzyme (lock & key model) Once it binds, the active site changes shape, forming the enzyme-substrate complex which breaks/forms the bonds necessary to form the products of the reaction which are then released Once it binds, the active site changes shape, forming the enzyme-substrate complex which breaks/forms the bonds necessary to form the products of the reaction which are then released

19. Factors such as pH, temperature, concentration and other substances can affect an enzymes function Factors such as pH, temperature, concentration and other substances can affect an enzymes function

20. Main Ideas Activation energy is the energy required to begin a reaction Activation energy is the energy required to begin a reaction Catalysts are substances that alter chemical reactions by speeding up the reaction Catalysts are substances that alter chemical reactions by speeding up the reaction Enzymes are biological catalysts Enzymes are biological catalysts

21. Properties of Water Chemical formula - H 2 O Chemical formula - H 2 O Molecule is in a “bent” Molecule is in a “bent”shape Electrons are shared unequally Electrons are shared unequally Oxygen (-) Oxygen (-) Hydrogen (+) Hydrogen (+) Polarity is caused from having two oppositely charged ends in a molecule (ex. magnet) Polarity is caused from having two oppositely charged ends in a molecule (ex. magnet)

22. “Opposites attract” forming hydrogen bonds “Opposites attract” forming hydrogen bonds Weak interaction Weak interaction between molecules Forms between a Forms between a hydrogen (H) and a oxygen (O), fluorine (F), or nitrogen (N) atom

23. These unique properties of water are important for the survival and homeostasis of living things These unique properties of water are important for the survival and homeostasis of living things Ex. Surface tension, capillary action, universal solvent, floating ice, adhesion, cohesion Ex. Surface tension, capillary action, universal solvent, floating ice, adhesion, cohesion

24. Mixtures with Water Mixture – combination of two or more substances which retain their own individual characteristics and properties Mixture – combination of two or more substances which retain their own individual characteristics and properties Types: Types: Homogeneous Homogeneous Heterogeneous Heterogeneous

25. Homogeneous mixture Homogeneous mixture Uniform composition throughout Uniform composition throughout Also known as a solution which Also known as a solution which contains two parts Solvent – substance in which another substance is dissolved Solvent – substance in which another substance is dissolved Solute – substance being dissolved Solute – substance being dissolved Ex. Salt water, saliva, flavored drinks, air Ex. Salt water, saliva, flavored drinks, air

26. Heterogeneous mixture Heterogeneous mixture Components remain distinct (individual) Components remain distinct (individual) Ex. Suspensions (sand in water, salad), colloid (fog, smoke, butter, mayonnaise, milk, paint, ink, blood) Ex. Suspensions (sand in water, salad), colloid (fog, smoke, butter, mayonnaise, milk, paint, ink, blood)

27. Acids Acids Created when a substance Created when a substance containing hydrogen is dissolved in water Releases hydrogen ions (H + ) Releases hydrogen ions (H + ) The more H + ions, the more acidic The more H + ions, the more acidic a solution becomes Ex. HCl, HSO 4 Ex. HCl, HSO 4

28. Bases Bases Created when a substance dissolved in water releases hydroxide ions (OH - ) Created when a substance dissolved in water releases hydroxide ions (OH - ) The more OH - released, the more basic the solution becomes The more OH - released, the more basic the solution becomes Ex. NaOH Ex. NaOH

29. pH pH The amount of ions in a solution determines the strength of an acid or base The amount of ions in a solution determines the strength of an acid or base pH is a scale which measures the amount of H + ions in a solution pH is a scale which measures the amount of H + ions in a solution Scale from 0-14 Scale from 0-14 Acidic solution range from pH 0 – pH 6 Acidic solution range from pH 0 – pH 6 Neutral solutions at pH 7 Neutral solutions at pH 7 Basic solutions range from pH 8 – pH 14 Basic solutions range from pH 8 – pH 14 pH can be identified by using pH indicator paper pH can be identified by using pH indicator paper

31. Majority of cells carry out metabolism between pH 6.5 and pH 7.5 Majority of cells carry out metabolism between pH 6.5 and pH 7.5 Buffers are mixtures that can react with acids or bases to keep the pH within a certain range (maintenance of homeostasis) Buffers are mixtures that can react with acids or bases to keep the pH within a certain range (maintenance of homeostasis) Ex. Pepto bismol, tums Ex. Pepto bismol, tums

32. Main Ideas Water is a polar molecule Water is a polar molecule Solutions are homogeneous mixtures formed when a solute is dissolved in a solvent Solutions are homogeneous mixtures formed when a solute is dissolved in a solvent Acids are substances that release hydrogen ions into solutions Acids are substances that release hydrogen ions into solutions Bases are substances that release hydroxide ions into solution Bases are substances that release hydroxide ions into solution pH is a measure of the concentration of hydrogen ions in a solution pH is a measure of the concentration of hydrogen ions in a solution