Introduc8on to Chemistry
• Atoms -‐ smallest par8cle of an element that has the elements proper8es
• protons (+) = Atomic number • neutrons (no charge) • Protons and neutrons together make up the nucleus
• electrons (-‐) – used to form bonds with other elements
Electrons
• found in regions of space called electron shells (energy shells) • each shell can hold a limited number of electrons
• for atoms with atomic numbers of 18 or less, the following rules apply: • the first shell can hold up to 2 electrons • the second shell can hold up to 8 electrons • the third shell can hold up to 8 electrons • lower shells are filled first • if the outermost shell is full, the atom is stable
Molecules and Compounds 1. Molecule: when two or more atoms
combine (usually for nonmetals) Organic compounds all contain CARBON!! 2. Compound: when two or more atoms
of different elements combine – Two types 1. Covalent 2. Ionic
Covalent Bond
Formed when atoms share electrons. They “hold hands”.
• Hydrogen atoms form single bonds • Oxygen atoms form two bonds • Nitrogen atoms form three bonds • Carbon atoms form four bonds
2-‐11
Ions
Ion • an atom that has gained or lost an electron(s) • an electrically charged atom • atoms form ions to become stable
• a posiMvely charged ion is formed when an atom loses an electron(s)
• a negaMvely charged ion is formed when an atom gains an electron(s) 2-‐9
Ionic Bond
• an aOracMon between an atoms that are negaMvely and posiMvely charged • “opposites aOract”
Ionic Bond
• formed when electrons are transferred from one atom to another atom
Review
Name and describe the two types of chemical bonds. What is an ion? How are ions needed by living things?
Ions allow living organisms to use elements to construct other compounds necessary for its survival.
– In a polar covalent bond • Electrons are shared unequally
between atoms, creating a polar molecule
• Water is a polar molecule! (–) (–)
(+) (+)
O
H H
1. Water is the solvent of life. Being polar allows water to dissolve ionically bonded compounds easily. When compounds dissolve in water they form a solution.
+
–
–
–
–
– –
–
–
– – +
+ +
+ +
Na+
+
Na+
Cl–
Ion in solu8on Salt
crystal
Cl–
Proper8es of Water
Proper8es of Water 2. Hydrogen bonds make water cohesive. The water molecules “stick” to each other, so one H2O molecule holds on to another H2O molecule. This creates surface tension.
Proper8es of Water 3. Water is adhesive (holds on to
different/other substances)
ex: molecules can move from a plant’s roots to its leaves
• Capillary AcMon Surface tension is also responsible for another phenomena known as capillary ac8on. Capillary acMon occurs when water climbs upward through a small space, defying gravity due to the forces of adhesion and surface tension.
Proper8es of Water 4. Expansion – water expands when it freezes, which is opposite to most substances
– results in ice having a lower density than liquid water so the ice floats
-‐-‐ ponds “freeze on top” so organisms are able to live underneath the ice layer. -‐-‐ problem for roads, water will get in cracks of the pavement and freeze and it will cause the roads to crack and have potholes.
Proper8es of Water 5. Water has unique thermal properties
a. high specific heat b. high boiling point c. high thermal conductivity d. good evaporative coolant (sweating)
*also called heat of vaporization So, as our sweat evaporates, we begin to feel cooler.
What is the pH scale? pH=power of hydrogen
• Measures the concentra8on of (hydrogen) H+ ions
• Acids -‐ pH number below 7 and a high number of H+ ions (low amount of OH-‐)
• Bases -‐ pH number above 7 and have a high number of OH-‐ (low amount of H+)
• Pure water is neutral and has a pH of 7.0
Acid rain -‐-‐contains sulfuric acid and nitric acid
* Acid rain pH < 5.6 * Acid rain washes away vital
minerals from soil, kills aqua8c organisms & strip nutrients from plants
Inorganic Substances-do NOT contain carbon
• Water – Most abundant in living things – Universal Solvent – Most reactions occur in water – Transports wastes, nutrients, etc. – Absorbs heat
• Oxygen – Must have in cellular respiration to release energy
• Carbon Dioxide – Waste product of cellular respiration
• Salts – Major sources on ions used in metabolic processes – Na, Cl, K, Ca, Mg, P
Organic substances-‐all contain carbon.
Name the 4 major types of organic macromolecules are: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids
#1- Carbohydrates • Provides immediate energy for metabolic activites
• Made of C, H, O
• Ratio 1:2:1 (C6H12O6)
• Monosaccharides: simple sugars (glucose) – These are the building blocks (monomers)
• Disaccharides: two simple sugars combined together (lactose)
• Polysaccharides: complex carbohydrates (glycogen, cellulose and starch)
#2- Lipids • Insoluble in water • Typically 3 fatty acids and 1 glycerol
(Triglycerides) • Store energy and have more energy than
carbs • Made of C, H, O Same elements in carbs,
just don’t have the 1:2:1 ratio. • Examples-Fats, oils, waxes, steroids,
cholesterol • Lipids provide insulation, protection,
structure of cell membranes
#3- Proteins • Provide energy after carbs and lipids
are used up. • Provide structure, movement of
muscles, transport, regulation, defense for the body
• Examples-hormones, enzymes, receptors, and antibodies, hair, nails, hooves
• Building block (monomer) is the amino acid – 20 amino acids of which 12 are
essential • Made of C, H, O, N • Held together by hydrogen bonding
(peptide bonds) so heat, pH change, radiation, etc. affect the bonding
33
An enzyme is a special kind of protein
1. Most enzymes are proteins that can speed up a chemical reaction and lower the activation energy needed.
2. Enzymes act as catalysts, which make a reaction go faster but without themselves being used up. 3. Usually end in -ase.
1. Substrate-‐ substance being changed by enzyme
2. AcMve site-‐ region on enzyme where substrate aOaches (this is the enzyme substrate complex)
*Enzymes work by either breaking or forming compounds.
* As an enzyme works, it combines with it substrate and converts it to products.
Chemical ReacMons and Enzymes
36
Factors that can affect Enzyme activity
• Temperature-‐low temps can make enzymes inacMve, high temps can denature the enzyme
• pH • ConcentraMons of substrates or enzymes
#4- Nucleic Acids • Form genes and take part in
protein synthesis • 2 Kinds: -DNA (Deoxyribonucleic Acid) -RNA (Ribonucleic Acid) • Made of C, H, O, N, P • Building block (monomer) is a nucleotide. Nucleotides are made of a sugar, phosphate, and a N base.
DNA vs. RNA
• DNA is double stranded • Contains the sugar deoxyribose • Has nitrogen bases called adenine (A) cytosine (C) thymine (T) guanine (G)
• RNA is a single strand • Contains the sugar ribose * Has nitrogen bases called adenine (A) cytosine (C) Uracil (U) guanine (G)
substrate
Ac8ve site
enzyme
products
ENZYME PRACTICE
1. Label the diagram with these terms: products, active site, enzyme, substrate
2. Answer true of false to the following statements:
a. _______ One enzyme can be used for many different types of chemical reactions. b. _______ Enzymes are used only once because they change shape after a reaction occurs. c. _______ Enzymes speed up reactions. d. _______ Raising the temperature will not change the rate of a reaction that uses an enzyme e. _______ Enzyme require specific pH levels.
F F
F T
T
41
Releasing Energy From ATP • ATP is constantly being used and remade by cells
• ATP provides all of the energy for cell activities
• The high energy phosphate bonds can be BROKEN to release energy
42
Releasing Energy From ATP
• Adding A Phosphate Group To ADP stores Energy in ATP
• Removing A Phosphate Group From ATP Releases Energy & forms ADP
Loose
Gain
43
Cells Using Biochemical Energy Cells Use ATP For: • Active transport • Movement • Photosynthesis • Protein Synthesis • Cellular respiration • All other cellular reactions
____________ __________ ___________________
SecMon 8-‐1
ATP
Go to Sec8on:
Adenine 5-‐carbon sugar Phosphate Groups
-‐ Adenosine Triphosphate
44
+
45
Energy
+
How energy is released?
A phosphate is removed by breaking the bond between the second and third
phosphate-‐releasing ENERGY!
Importance of ATP
o Energy storage chemical for cell processes
o Most of ATP is produced via electron transport chain
o Main reason that cells need oxygen: to allow them to make lots of ATP
o Involved in both photosynthesis and respira8on
Photosynthesis
6 CO2 + 6 H2O + Sunlight à C6H12O6 + 6 O2 Carbon Dioxide + Water + Sunlight à Glucose + Oxygen
49
Factors AffecMng the Rate of Photosynthesis
• Amount of available water
• Temperature • Amount of available light energy
Photosynthesis has 2 stages: 1. Light Dependent Reac8on *happens in the thylakoids (grana) • Uses light energy • Produce Oxygen from water • Convert ADP to ATP 2. Light Independent Reac8on Also known as the Calvin Cycle or Dark Reac8on * happens in the open area called the stroma
All cells carry on some form of cellular respiraMon. Most plants and animals require oxygen.
Cellular Respira8on
C6H12O6 + 6 O2 à 6 CO2 + 6 H2O + 38 ATP Glucose + Oxygen à Carbon dioxide + Water + Energy
How much energy does cellular respiration produce???
1) Glycolysis: Produces 2 ATP per Glucose
2) Krebs Cycle =2 ATP 3) Electron Transport Chain: 32 ATP
molecules per Glucose
Grand Total = 36 ATP
What happens if oxygen is not available after glycolysis???
• Instead of pyruvic acid entering the mitochondria, fermentation occurs in the cytoplasm
• It is known an anaerobic respiration
• There are 2 types: Alcoholic Lactic Acid
Reactants (what you start with)
Photosynthesis – Carbon dioxide – Water
Cellular Respira8on -‐-‐ Glucose (sugar) -‐-‐ Oxygen
Oxygen
Products (what you end with)
Photosynthesis – Glucose (sugar)
Cellular Respira8on -‐-‐Chemical energy = ATP
Oxygen