Lecture 3: Chemistry & Biomolecules (PDF)

LECTURE 3 Chemistry & Biomolecules © Samuel Richer 2024 (adapted from Maryse Dagenais & Jason Lapoint) To Do Before Next Class Theory ❑ Review Lecture 3 ❑ Assignment #2 Chemistry Laboratory ❑ Read all of Lab 2 Bones of the Skeletal system posted on Lea ❑ Read a...

LECTURE 3 Chemistry & Biomolecules © Samuel Richer 2024 (adapted from Maryse Dagenais & Jason Lapoint) To Do Before Next Class Theory ❑ Review Lecture 3 ❑ Assignment #2 Chemistry Laboratory ❑ Read all of Lab 2 Bones of the Skeletal system posted on Lea ❑ Read all of Lab 3 Joints posted on Lea Additional Resources: Martini, Nath and Bartholomew. (2017) Fundamentals of Anatomy and Physiology. p.27-40. 2.1 Elements and Atoms: The Building Blocks of Matter - Anatomy and Physiology 2e | OpenStax 2.2 Chemical Bonds - Anatomy and Physiology 2e | OpenStax 2.3 Chemical Reactions - Anatomy and Physiology 2e | OpenStax 2.4 Inorganic Compounds Essential to Human Functioning - Anatomy and Physiology 2e | OpenStax Lecture 2: Learning Objectives 1. Review the chemical terms: atom, element, molecule, macromolecule, organic and inorganic compound, ionic bond, covalent bond, polar covalent, Ion, acid, base, buffer, pH, salt 2. Define the following terms: anabolism, synthesis, catabolism, decomposition. 3. Explain the importance of water. a) Describe the structure of water. b) Why is water a polar molecule? Be able to draw water as part of your explanation. c) Define and draw the hydrogen bond. d) List the functions of water that support life and explain each. 4. Define the terms: monomer, polymer, and macromolecule a) Describe the dehydration synthesis reaction using examples. b) Describe the hydrolysis reaction using examples. Table of Contents 1. Basic particles of matter 2. Chemical bonds Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bonds 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Basic Particles of Matter Compound Formed when 2 different elements join together. All Molecule compounds are molecules Two or more atoms but not all molecules are compounds held together by a chemical bond Elements A pure substance consisting of one type of atom and can be identified by its atomic # (# of Atoms protons). All elements are Smallest unit of found on the periodic table of elements and have a matter that still chemical symbol retains the properties of an element. matter Matter Anything that takes up space and has mass. Basic Particles of Matter The Atom The Bohr model of atoms resembles our solar system: negatively charged electrons orbiting a dense nucleus composed of positively charged protons and neutral neutrons. quantum mechanics further expanded our understanding of atoms by developing orbital theory; existence of electron clouds. Basic Particles of Matter The Atom Atoms are mostly empty space The Nucleus: Protons and neutrons create the atomic nucleus. The mass of each proton and each neutron is 1 atomic mass unit (amu). The Electron Cloud: Electrons form a negatively charged cloud around the nucleus. Bohr Model Electrons have NO mass (0 amu). Basic Particles of Matter The Atom - The # of protons (p+), electrons (e-) & neutrons (n0) in an atom are different, depending on the element you are looking at. Because of this, each atom has a unique name, mass and size. Basic Particles of Matter The Atom ATOMIC NUMBER: # of protons (+) in the atom & is often the # of electrons* (*unless the atom is sharing or giving their electrons away) - = how elements are arranged in the periodic table Basic Particles of Matter The Atom ATOMIC NUMBER: # of protons (+) in the atom & is often the # of electrons* (*unless the atom is sharing or giving their electrons away) - = how elements are arranged in the periodic table ATOMIC MASS: the sum of the # of protons (+) & # of neutrons = i.e. how “heavy” the atom is (Remember that electrons are massless) ___ protons ___ protons ___ protons ___ electrons - ___ electrons ___ neutrons - ___ electrons - ___ neutrons ___ neutrons Basic Particles of Matter Isotopes Isotopes are versions of atoms that have different mass numbers o This is when atoms of the same element have different # of NEUTRONS Protons: __ Protons: __ Protons: __ Neutrons: __ Neutrons: __ Neutrons: __ C C C 6 6 6 12 13 14 “Normal” Carbon Carbon-13 isotope Carbon-14 isotope ABUNDANCE IN NATURE ~99% ~1% rare Basic Particles of Matter Isotopes Protons: 6 Protons: 6 Protons: 6 Neutrons: 6 Neutrons: 7 Neutrons: 8 6 C 12 6 C 13 6 C 14 Non-Stable/Radioactive isotopes: isotope Stable isotopes: nuclei don’t have tendency in which the nucleus decays spontaneously, to lose particles giving off particles of energy Basic Particles of Matter Isotopes Biological applications Carbon dating for fossils Nuclear medicine (radioactive tracers) o Carbon-11 in PET scans o Radioactive glucose during PET scan (Fluorodeoxyglucose) Radiotherapy for cancer patients o Radioactive Cobalt-60 Table of Contents 1. Basic particles of matter 2. Chemical bonds Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bonds CHEMICAL BOND 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Bond Molecules A chemical reaction occurs when 2 or more atoms combine to form a Molecule, and an entirely new substance results (recall emergent properties). H2O: transparent, unreactive liquid Hydrogen: clear odourless, highly reactive gas Oxygen: clear odourless, highly reactive gas Chemical bond: a form of attraction between atoms that holds them together. Chemical Bond Valence electrons are the electrons farthest from the nucleus (in the last shell). They are crucial in determining the chemistry of the atom and its influence on other atoms! Valence: the number of covalent bonds that an atom can form Chemical Bond Atoms strive to fill their outer shell: rule of thumb: 2, 8, 8 rule Full shell How many valence electrons does carbon have and how many bonds can it make? Chemical Bond Based on the number of valence electrons Chemical Bonds can be… Attractions between Attractions between two or more two or more Atoms M-o-l-e-c-u-l-e-s Chemical Bond Bonds are attractions between 2 or more Atoms or M-o-l-e-c-u-l-e-s There are 4 types of bonds we will study: Ionic bonds Polar covalent bond Non-Polar covalent bond Attractions between two or more Atoms − δ+ 𝛿 Within Molecule Complete transfer of electrons Electrons are shared unequally Electrons are shared equally Full charges on atoms Partial charges on atoms No charges on atoms Attraction between 2 or more M-o-l-e-c-u-l-e-s Hydrogen bonds Between Molecules  Attractions between two or more Atoms Chemical Bond Based on the number of valence electrons Chemical Bonds can be… ION IC BO NDS COVALENT BONDS (transfer of electrons) (sharing of electrons) − 𝛿 δ+ Cl- Na+ e- POLAR COVALENT NON-POLAR COVALENT with electrons “stolen” & electrons shared unequally electrons shared equally transferred from one atom to pulled more to 1 atom creating a + Atoms are equally pulling the other partial charge positive pole (𝛿 ) & negative pole (𝛿 -)  5. Chemical Bonds How do we determine whether 2 Bonds can atoms be…an: form ionic bond polar covalent bond or Cl- non-polar covalent? Na+ e- with electrons “stolen” and with electrons with electrons transferred from one atom to shared unequally and Electronegativity shared equally the other pulled more to one side of the two atoms I O N I C (transfer of electrons) C O V A L E N T (sharing of electrons) Between Metal & Non-Metal Between Non-Metal & Non-Metal Chemical Bond The ability for an atom to attract electrons from another atom Electronegativity  Electronegativity Values The attraction that electrons feels for a particular nucleus depends on: the number of protons in the nucleus the distance from the nucleus High electronegativity = strong attraction for electrons of other atoms Low electronegativity = low attraction for electrons of other atoms Table of Contents 1. Basic particles of matter 2. Chemical bonds Ionic bonds Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bonds Complete transfer of electrons Full charges on atoms 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Bond Ionic bonds What happens when the difference between electronegativities is very large, like between metals and nonmetals? Cl- Na+ e- Electrons are fully transferred and “stolen”, leading to the production of ions (where protons no longer equal electrons). Chemical Bond Ions 11 + protons 17 + protons 11 - electrons 17 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ 11Na + Cl 11 protons 11 neutrons - 11Na + 10 electrons 17 Cl 17 - 11 + protons 17 + protons 10 - electrons 18 - electrons Net charge: _____ Net charge: _____ If 1 atom is much more successful at attracting electrons, both atoms become charged IONS.  Chemical Bond Ions 11 + protons 17 + protons 11 - electrons 17 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ The LESS The MORE electronegative atom LOSES the electronegative atom GAINS the 11Na + electron, becoming a positive ION electron, becoming a negative ION Cl 11 protons 11 neutrons - 11Na + 10 electrons 17 Cl 17 - 11 + protons 17 + protons 10 - electrons 18 - electrons Net charge: _____ Net charge: _____ If 1 atom is much more successful at attracting electrons, both atoms become charged IONS. Chemical Bond Ions 11 + protons 17 + protons 11 - electrons 17 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ 11Na + Cl 11 protons + 11 neutrons -- 11Na + 10 electrons 17 Cl 17 - 11 + protons 17 + protons 10 - electrons 18 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ Chemical Bond Ions 11 + protons 17 + protons 11 - electrons 17 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ This is an atom of This is an atom of sodium (Na) chlorine (Cl) If 1 atom is much more successful at 11Na + attracting electrons, both atoms become charged ions. 11Na + + Cl 17 Cl -- 17 - 11 + protons 17 + protons 10 - electrons 18 – electrons Net charge: _____ Net charge: _____ Valence electron: ____ Valence electron: ____ This is an ion of sodium (Na+) This is an ion of chlorine (Cl-) Chemical Bond Ionic bonds If 1 atom is much more successful at attracting electrons, both atoms become charged ions. Chemical Bond Ionic bonds Ions are atoms that received or have given up valence electrons. It is an atom or - molecule in which the total number of electrons of protons - is not equal to the total number , giving the atom a net positive or negative charge. The atom losing an electron The atom gaining an electron having a (+) charge is called a having a (-) charge is called an CATION ANION *rule of thumb: between metals and non-metals Remember ONLY electrons move around in atoms - Chemical Bond Ionic bonds Ionic compounds are also called salts: Found in nature as crystals Crystals are made up of many cation-anion interaction partners Cl- arranged in 3D lattices Na+ Na+ Cl- Cl- Na+ H2O C6H12O6 Na+ & Cl- (water) (glucose/sugar) (from NaCl salt) Ions are charged and can Not an ION Not an ION Is an ION produce electricity due to cannot conduct cannot conduct can conduct the movement of charges Table of Contents 1. Basic particles of matter 2. Chemical bonds Non-Polar covalent bond Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bonds Electrons are shared equally No charges on atoms 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Bond Non-Polar Covalent Bond Covalent bonds result from the sharing of valence electrons between 2 atoms Covalent bonds are considered strong bonds Notice how electrons between two hydrogen’s are shared to form a single covalent bond. Notice how electrons between a hydrogen and + Oxygen atom are shared = and form two separate single covalent bonds. Take Note! When we draw covalent bonds, we draw them using a “full” line connecting the two atoms. Chemical Bond Non-Polar Covalent Bond How many covalent bonds can be formed between carbon and hydrogen? How many bonds are there? How many electron pairs are shared? How many electrons are shared? Table of Contents 1. Basic particles of matter 2. Chemical bonds Polar covalent bond Ionic Bonds − Nonpolar Covalent Bonds δ+ 𝛿 Polar Covalent Bonds Hydrogen Bonds Electrons are shared unequally Partial charges on atoms 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Bond Polar Covalent Bond When something is shared, is it always shared equally? NO, NOT ALWAYS Recall: Atoms pull electrons more or less depending on their electronegativity values Sometimes one of the partners “hogs” the shared electrons. NON-POLAR COVALENT BONDS POLAR COVALENT BONDS − δ+ 𝛿 Chemical Bond Polar Covalent Bond Polarity is the distribution of electrons in a bond In NON-POLAR COVALENT bonds, the electron pairs are shared equally because the 2 atoms are equally similar in electronegativity. − In POLAR COVALENT BONDS, electron 𝛿 − 𝛿 pairs are not shared equally δ+ 1 atom is more electronegative than the other δ+ δ+ Unequal sharing of electrons causes + a partial positive pole 𝛿 and partial − negative pole 𝛿 for each atom. The more electronegative an atom, the more strongly it pulls shared electrons toward itself. Chemical Bond Polar Covalent Bond Water (H2O) is a POLAR COVALENT MOLECULE since electrons aren’t shared equally o part of the molecule got electrons pulled away and is slightly positive δ+ o part of the molecule hogged electrons away and is slightly negative δ– + 𝛿 + 𝛿 + + 𝛿 𝛿 Chemical Bond Polar Covalent Bond δ– oxygen is more electronegative Shared electrons are pulled more towards the atom with greater electronegativity. o Shared electrons are around the oxygen O atom more than the hydrogen atoms. o This creates partial charges δ+ and δ– H H A greater desire for electrons means greater electronegativity; the major atoms involved in δ+ δ+ covalent bonding are… O>N>C≈H hydrogen is less electronegative Table of Contents 1. Basic particles of matter 2. Chemical bonds Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bond Hydrogen Bonds 3. Chemical reactions Attraction between 2 or more M-o-l-e-c-u-l-e-s 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Bond Hydrogen Bonds δ– The positive dipole ( δ+ ) of a Hydrogen δ+ atom in a polar covalent bond can create a hydrogen bond. This occurs when it is chemically attracted to another electronegative atom with a negative dipole (δ–) usually, Oxygen or Nitrogen of another molecule. δ+ Hydrogen-Bond Attraction between 2 or H-Bonds are not δ– more M-o-l-e-c-u-l-e-s physical bonds- they are weak attractions. (represented by a dotted line between parts of molecules. δ+ δ+ 43 Chemical Bond Hydrogen Bonds δ– Water O H δ+ (H2O) H-BOND H δ+ Hydrogen-Bond H-BOND H-BOND δ– Ammonia (NH3) N H H δ+ H δ+ H-BOND δ+ Individual hydrogen bonds are “weak Hydrogen bond interactions result when a hydrogen bonds” (can easily be disrupted & broken). atom covalently bound to an electronegative atom However… collectively they are strong. (such as Oxygen or Nitrogen ) interacts with an electronegative atom of another molecule. Chemical Bond Hydrogen Bonds CONFUSION ALERT δ– δ+ O-H bonds are polar covalent Attraction between 2 bonds Attractions between or more M-o-l-e-c-u-l-e-s two or more Atoms δ+ Hydrogen-Bond δ– Within Molecule N-H bonds are polar covalent δ+ δ+ bonds δ+ Chemical Bond Hydrogen Bonds Where do we see H-bonds in Biology? H2O as the “solvent of life”? Protein folding The covalent bonds are both polar allowing hydrogen However, H-bonds can be formed by many other bonding between water molecules. compounds as well; proteins use H-bonds to fold Each hydrogen can form 1 H-bond with another oxygen upon themselves. Each oxygen can have 2 H-bonds with other hydrogens. Table of Contents 1. Basic particles of matter 2. Chemical bonds Ionic Bonds Nonpolar Covalent Bonds Polar Covalent Bonds Hydrogen Bonds 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Chemical Reactions What is a chemical reaction? When atoms in compounds break apart and rearrange to form new compounds with new properties, a CHEMICAL REACTION has occurred. Some evidence that a chemical reaction has taken place includes: Heat production Color change Precipitate formation Gas production Chemical Reactions What goes on during a chemical reaction? Reactants are rearranged to form products: x[A] + y[B] → z[AB] Cells use chemical reactions to store chemical energy. Chemical energy is used to fuel other reactions to help maintain homeostasis. Usable Energy: ATP Carbohydrates + Heat + + O2 CO2 + Water Chemical Reactions 2 types of chemical reactions for a reaction to take place, energy is either spent or released: Exergonic reaction: Endergonic reaction: Breaking down molecules Building molecules releases the energy stored requires the energy in chemical bonds. stored in ATP. Releases energy & occurs Energy is needed & is not spontaneously spontaneous Example: cellular respiration Example: Muscle growth glucose + O2 → CO2 + H2O + energy (ATP) amino acids + energy (ATP) → protein Chemical Reactions Recall the chemical reactions in metabolism: = The sum of all chemical processes (Catabolic and Anabolic Reactions) = Energy processing: rearranging atoms in molecules to make and consume ATP Food molecules the many molecules that form muscles ATP CATABOLIC PATHWAYS ANABOLIC PATHWAYS Digesting large food molecules Using ATP energy to build and grow into smaller ones muscles during exercise the many building blocks for building in the body Chemical Reactions Usable Energy: ATP 1. Glucose catabolism during cellular respiration in the mitochondria turns adenosine diphosphate (ADP) into the high energy adenosine triphosphate (ATP) molecule. 2. ATP is charged with chemical energy stored in its bonds (currency of the cell ). 3. When ATP is converted to ADP, a phosphate is transferred to another molecule which drives most cellular work in the body. 2. “Charged” version ☺ 3. Using ATP energy to build and 1. Making ATP from energy released during grow muscles during exercise food breakdown in cellular respiration “spent” version  Chemical Reactions Energy Coupling For a reaction to take place, energy is either spent or released By coupling two reactions, you can provide sufficient energy for an endergonic reaction to proceed; our body does this all the time: Chemical Reactions Most reactions are in dynamic equilibrium Dynamic Equilibrium = a state of balance between continuing processes At any given temperature or pressure level, reactions will equilibrate at the same product concentration to reactant concentration ratio. Le Chatelier’s Principle explains that changing the concentration of reactants or products will influence the direction of a reaction. Initial Condition Final Condition At Equilibrium: At Equilibrium: A B A B A B A A + B B A B A A A + B B B A B A B A B x[A] y[B] z[AB] x[A] y[B] z[AB] If [A] or [B] is reduced: At New Equilibrium: A + B A B A B A B A A + B B A B A B x[A] y[B] z[AB] x[A] y[B] z[AB] If [AB] is reduced: At New Equilibrium: A B A A + B B A B A A + B B A B x[A] y[B] z[AB] x[A] y[B] z[AB] Chemical Reactions Why are chemical reactions important? They’re responsible for creating & breaking down the biomolecules. Types of chemical compounds Organic compounds are chemical compounds Inorganic compounds do not contain that have carbon covalently bound to hydrogen carbon and hydrogen (if they do, there are no Carbon remains an important atom in forming the C-H bonds). biomolecules due to how it can bond: Ex: inorganic phosphate Chemical Reactions Biomolecules The major macromolecules are mostly P-O-L-Y-M-E-R-S : complex molecules made up of repeated simpler MONOMER units connected by covalent bonds. Single unit: Monomers A chain of monomers forms a P-O-L-Y-M-E-R  Chemical Reactions Types of chemical reactions Monomer Polymer How do 2 or more monomers form a polymer? This is a dehydration synthesis reaction This is an anabolic reaction requiring energy 2 monomers bond together through the loss of a water molecule (condensation)  Chemical Reactions Types of chemical reactions Monomer Polymer Polymer Monomer How do 2 or more monomers form a polymer? How do polymers break down into monomers? This is a dehydration synthesis reaction Polymers are disassembled to monomers by hydrolysis decomposition reaction This is an anabolic reaction requiring energy This is a catabolic reaction releasing energy 2 monomers bond together through the loss of a water molecule (condensation) Polymers split apart through the addition of a water molecule. Chemical Reactions Recall 1. What is a covalent bond? 2. What is a polar covalent bond? 3. What is a hydrogen bond? Table of Contents 1. Basic particles of matter 2. Chemical bonds 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Importance of Water Water is polar The polar nature of water makes it very important because this polarity allows water to form intermolecular Hydrogen-bonds between water molecules Attraction between 2 or more M-o-l-e-c-u-l-e-s Importance of Water Hydrophilic & Hydrophobic HYDROPHILIC HYDROPHOBIC Water Loving Water Fearing 🫣 Compounds that are polar dissolve Compounds that are non-polar DON’T in water which is also polar dissolve in water (which is polar) These compounds are considered These compounds are considered hydrophilic (water-loving ) hydrophobic (water-fearing 🫣 ) Water is important because of its polarity, and this affords it many other properties… Importance of Water 1. Cohesion & Adhesion These forces influence some of water’s special properties. H-bonds make water molecules Adhesion “adhesive”: meaning that they stick to certain polar surfaces. H-bonds also make water molecules Cohesion “cohesive”: meaning that they have a strong tendency to stick to each other. Importance of Water 2. Good Solvent Water (polar) can dissolve any other polar substance (anything with a charge or partial charge) Water can dissolve: Small Ionic compounds into separate Large polar compounds ions surrounded by H2O molecules. are similarly dissolved. Importance of Water 3. Reactivity In the human body, chemical reactions occur in water. However, in some chemical reactions, water molecules can be… OR products, as in dehydration reactants, as in hydrolysis reactions synthesis reactions Importance of Water 4. High Heat Capacity What is temperature? A measure of the average kinetic energy (motion) of the particles in a sample of matter, expressed in terms of degrees designated on a standard scale. Motion of the particles INCREASES with temperature. What is heat capacity? Copper: 0.092 cal/(g x °C) Aluminum: 0.214 cal/(g x °C) Heat capacity refers to the amount of heat that must be absorbed or O2: 0.217 cal/(g x °C) Ethanol: 0.583 cal/(g x °C) lost to change the temperature of a substance by 1°C. Water: 1.000 cal/(g x °C) Importance of Water 4. High Heat Capacity Why does water have such a high specific heat? Because of hydrogen bonds! When water is heated, the energy must first be absorbed to break the bonds. Only after the bonds are broken can the energy increase the movement of the water molecules. Water therefore resists temperature change. What does this mean for the body? Vaporized water molecules lost to the environment (i.e. sweating) carries a lot of heat away from the body Water absorbs a lot of heat and stabilizes our body temperature by resisting temperature change Importance of Water 5. Lubrification By reducing friction between solid surfaces, water acts as a great lubricant. A thin layer of serous fluid between larger structures will reduce the friction between them this allows your organs to slide against each other in your abdominal cavity without breaking ☺ Table of Contents 1. Basic particles of matter 2. Chemical bonds 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules Acids & Bases Water Dissociates A water molecule can spontaneously break into (OH-) and (H+) O- O O- O H +H H H H+ H H H O O- O O- This always happens, and there are usually H +H the same amount of (OH-) and (H+) H H H +H H H O- O O- O H +H H H H +H H H Acids & Bases Acidic Substances Molecules that can release H+ It increases the [ ] of H+ in a solution It decreases the [ ] of OH- in a solution Acids & Bases Basic Substances Molecules that accept/combine with H+ It decreases the [ ] of H+ in a solution It increases the [ ] of OH- in a solution  Acids & Bases pH Scale pH value indicates the concentration of H+ ion in a solution and ranges from 0 to 14 Low pH (acidic) mean high [H+] concentration lower values being acidic Neutral pH mean equal H+ and 7 being neutral and OH- concentration High pH (basic) mean low H+ concentration higher values being basic Acids & Bases pH Scale Solutions are more basic Solutions become more (alkaline) when a compound acidic when a compound can remove H+ ions from the can add H+ ions to the solution (or by increasing the solution (or by decreasing amount of OH- ions). the amount of OH- ions). Acids (like HCl, H2CO3, and H2SO4) and bases (like NaOH or KOH) will influence the pH of a solution; why? Bases dissociate into Na+ + OH-, where the Acids dissociate into H+ + Cl-, where the OH- combines with H+ ions to make water. concentration of H+ increases. Acids & Bases Buffers The internal pH of most living cells must remain very close to pH 7 Buffers minimize changes in concentrations of H+ and OH− in a solution The forward reaction can donate hydrogen ions when they have been depleted. Bicarbonate Carbonic Acid Ion ACID BASE The reverse reaction can accept hydrogen ions from the solution when they are in excess Acids & Bases Buffers Buffers minimize the change in H+ and OH− in a solution. If the blood is too acidic: the acid will donate its H+ to the HCO3- (a base) and shift the equation to the left causing the concentration of free H+ will change minimally. H+ Acids & Bases Buffers Buffers minimize the change in H+ and OH− in a solution. If the blood is too acidic: the acid will donate its H+ to the HCO3- (a base) and shift the equation to the left causing the concentration of free H+ will change minimally. H+ If the body is too basic: the base OH− will steal a H+ from the H2CO3 (an acid) and shift the equation to the right, and the concentration of free H+ will change minimally. OH- Acids & Bases pH values in the human body Acids & Bases Buffers in the human body This buffering system can minimize shifts in pH up to a point. Certain metabolic products acidify our blood, like carbon dioxide and lactic acid Carbonic Bicarbonate Acid Ion ACID BASE Lungs reduce the presence Excrete H + ions and of carbonic acid in the reabsorb HCO3- by blood by exhalating CO2 the kidneys Help maintain a blood pH range between 7.35 and 7.45. Acids & Bases Buffers in the human body How is H2CO3 created? Carbonic anhydrase combines H2O and CO2. Table of Contents 1. Basic particles of matter 2. Chemical bonds 3. Chemical reactions 4. Importance of water 5. Acids & Bases 6. Introduction to biomolecules  Introduction to Biomolecules The cells of living things are made up of 4 classes of large biomolecules LIPIDS NUCLEIC ACIDS CARBOHYDRATES PROTEINS Make up cell membranes Encodes & transmits Provides a source of 1. pores/pumps for transport & long term energy genetic information energy to the cell 2. enzymes to speed up reactions  Introduction to Biomolecules The cells of living things are made up of 4 classes of large biomolecules LIPIDS NUCLEIC ACIDS CARBOHYDRATES PROTEINS Make up cell Encodes & transmits Provides a source of 1. pores/pumps for transport membranes & long term genetic information energy to the cell 2. enzymes to speed up reactions energy acting as the border acting as the parliament of acting as Hydro Quebec of acting as bridges for transport agent of the cell the cell the cell and workers of the cell Introduction to Biomolecules The major macromolecules are mostly P-O-L-Y-M-E-R-S : complex molecules made up of repeated simpler MONOMER units connected by covalent bonds. Single unit: Monomers A chain of monomers forms a P-O-L-Y-M-E-R  Introduction to Biomolecules e.g. starch Not made up of Monomer Monosacharides (a.k.a. simple sugars) Amino Acid Nucleotide repeating monomers (20 different types) (5 different types) (but still has an organization!) Polymer Polysacharide Peptide/Protein Nucleic Acid Introduction to Biomolecules The macromolecules are composed of smaller units Most are P-O-L-Y-M-E-R-S: complex molecules made up of repeated simpler units (monomers) connected by covalent bonds. P-O-L-Y-M-E-R-S MONOMER Proteins Amino acids Nucleic acids Nucleotides Carbohydrates Monosaccharides Polysacharides Lipids (not always a polymer) Fatty acids Introduction to Biomolecules Monomer Polymer Protein Amino Acid 1 Amino Acid 2 Nucleic Acid Nucleotide 1 Nucleotide 2 Monosaccharide 1 Monosaccharide 2 Polysaccharide (disaccha ride in this case) Introduction to Biomolecules Breaking and Building Macromolecules ATP ATP CATABOLIC PATHWAYS ANABOLIC PATHWAYS Ex: Breaking down macromolecules Ex: Building macromolecules releases energy requires energy Assignment #2 Assignment #2 Review Take Away of the class ❑ Atoms are the smallest unit of matter and are composed of protons, neutrons, and electrons. ❑ Matter is composed of elements, whose basic units are atoms. Ions are atoms with an unusual number of electrons, while isotopes are atoms with an unusual number of neutrons. ❑ Atoms can interact by sharing or transferring electrons to form molecules and compounds. ❑ Ionic and covalent bonds are strong bonds, while compounds that share electrons unevenly can also interact via weaker H-bonds. ❑ Water’s many properties provide benefits to the human body. It dissolves substances, is involved in many chemical reactions, and influences thermoregulation. ❑ The concentration of H+ ions will determine the acidity or alkalinity of a solution. Buffers help prevent shifts in the pH of body fluids, helping maintain homeostasis. ❑ Biomolecules includes carbohydrates, proteins, nucleic acids, and lipids. They are commonly polymers (except some lipids) formed via dehydration synthesis and decomposed via hydrolysis. Review Questions to think about 1. What are the different components of an atom? 2. What type of bonds involve the sharing of electrons? 3. What is the difference between a polar and non-polar covalent bond? 4. What are the important characteristic of water and how do they help support life? 5. If I had more reactants to an equation at equilibrium, what does Le Chatelier’s principle suggests will happen? 6. How does a buffer minimizes change in pH?