MAIN IDEA: The properties of water make it well suited to help maintain homeostasis in an organism.

Do Now:
 Name one way our bodies use water to maintain homeostasis
 https://www.youtube.com/watch?v=HVT3Y
3_gHGg

Properties of Water
 Water is polar; universal solvent
 Water is cohesive.
 Water is adhesive.
 Water is less dense as a solid.

What is a solvent?
 What happens when you take kool-aid powder and pour it into a cup of water?
 Discuss with someone close to you; what is the solute? What is the solvent?

Polarity
 polar molecules - molecules that have an unequal distribution of charges
 Polarity is the property of having two opposite poles.
 hydrogen bond - weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom; happens b/c of polarity; strong type of van der Waals force

Cohesive
 Molecules of water – attracted to each other b/c of H-bonds
 Causes surface tension
 Allows water to form droplets
 Allows insects to rest on water’s surface

Adhesive
 Water forms Hbonds with molecules on other surfaces
 Allows water to travel up stems of plants
(capillary action)

Question…
 Is a meniscus an example of cohesion or adhesion?
 Discuss with someone close to you

Ice is less dense than water
 As water cools to 4 °C, it becomes more dense.
 When it freezes, it is less dense than liquid water.
 Nutrients in bodies of water mix.
 Animals live under frozen surface of bodies of water in winter.

Question…
 What would happen in winter to animals that live in lakes if water was more dense as a solid? Think
 Discuss with someone next to you

What is a mixture?
 Substances combine, but do not change chemically
 Can be separated easily
 No chemical change occurs
 Ex: tea, saltwater, salad dressing, bag of candy

Types of Mixtures
 Homogeneous – mixture looks the same throughout
 Ex: salt water, soda
 Heterogeneous – mixture is different throughout
 Ex: salad, salad dressing

Solutions
 Homogenous mixture
 Molecules of one substance mix evenly w/those of another (dissolves)
 2 parts:
 Solute – substance that is dissolved
 Solvent – substance that does the dissolving
 Name solute & solvent in salt water


Concentrations of solutions
Dilute – less solute
 Concentrated – more solute
 Saturated – solution has as much solute as it can hold.

Colloids

2 substances that don’t mix evenly
 Stay mixed
 Usually thicker than most liquids
 If light is shined through, it scatters –
Tyndall effect
 Ex: fog, milk, jell-o, cream

Tyndall Effect

Suspension

2 substance that don’t mix evenly
 Do not stay mixed
 Particles – heavy and settle
 Ex: blood, flour and water, aerosols, ice cream

Compare and contrast heterogenous and homogenous mixtures:

Acids and Bases
Acids
 release hydrogen ions (H+) when dissolved in water
 Ex: stomach acid, vinegar, citrus fruit
Bases
 release hydroxide ions(OH-) when dissolved in water
 Ex: ammonia, soap, blood

pH and buffers
 pH - measure of concentration of H+ in a solution
 Acidic solutions - pH values lower than 7.
 Basic solutions – pH values above 7.
 pH of 7 = neutral
 Buffer – mixtures that react with acids or bases to keep the pH in a neutral range

Water
 Water pH = 7 (neutral)
 Water splits into H + and OH -
 Equal amounts of each

Salts
 Formed when acid and base react
 Ex: NaOH + HCl  NaCl + HOH
 base acid salt water
 Needed to control many life processes

MAIN IDEA: Organisms are made up of carbon-based molecules.

Organic Chemistry
 Carbon is a component of almost all biological molecules.
 4 electrons in outer energy level, so 4 electrons to share in 4 covalent bonds

Carbon


Carbon makes covalent bonds with other elements, like hydrogen, oxygen, and nitrogen (CHON)
Carbon molecules – can be straight chains, branched chains, or rings

Macromolecules
 Carbon atoms join to form carbon molecules.
 Macromolecules - large molecules formed by joining smaller organic molecules together.
 Polymers - molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds.
 Each link - monomer

Monomer

Polymer

4 Main Organic Compounds
 Carbohydrates, lipids, proteins, and nucleic acids
 All needed for proper cell function and structure

Carbohydrates
 Carbon, hydrogen, oxygen in ratio of
1:2:1
 Ex: glucose = C
6
H
12
O
6
 Reduces to 1:2:1
 (CH
2
O) n
 Key energy source in most foods
 Provides structural support in cells
 Ex: sugars and starches

Monosaccharides
 Values of n ranging from three to seven are called simple sugars, or monosaccharides.
(saccharide = sugar)
 Building blocks of carbohydrates
 Ex: glucose, fructose

Longer Carbohydrates
 2 monosaccharides = disaccharide
 More than 2 = polysaccharide

Lipids
 Made mostly of carbon and hydrogen
 Nonpolar, so not soluble, or mostly insoluble, in water

Types of Lipids
 Phospholipids – make cell membranes
 Steroids/sterols – ex: cholesterol – in animal cell membranes
 Pigments – ex: chlorophyll
 Fats, oils, and waxes

Fats and Oils
 Store a LOT of energy
 Mostly C-H bonds, which have a lot of energy
 Structure usually – 3 fatty acids bonded to glycerol (called triglyceride)
 Fat if solid at room temp; oil if liquid at room temp

Fatty acids

Saturated fats = all C’s bonded to at least
2 H’s; single bonds between carbons; most animal fats (butter, lard, grease)
 Unsaturated = some double bonds between carbons (1 = monounsaturated; more than 1 = polyunsaturated); liquid at room temp (oils); healthier to eat
 Hydrogenated = H added to unsaturated fats to improve texture

Proteins
 Made of amino acids – small carbon compounds made of CHONS
(carbon, hydrogen, oxygen, nitrogen, sometimes sulfur)
 20 different amino acids

Amino Acid Structure
 Contain a central carbon atom

One of carbon’s bond is to hydrogen
 The other three bonds are with an amino group ( –NH2), a carboxyl group (–COOH), and a variable group ( –R).
 Bond between 2 amino acids = peptide bond

Complexity of Protein Structure
 Primary structure – number and order of amino acids joined together
 Chain of amino acids = polypeptide
 Secondary structure – chain folds into a 3-D shape: helix or pleat

Protein Structure

What are proteins for?
 Enzymes – promote chemical reactions
 Structure of organisms: collagen (skin, ligaments, tendons..), bone, hair, muscles
 Provide antibodies and hormones
 Allow muscle contractions, blood clots
 Hemoglobin (carries oxygen in blood)

Nucleic Acids
 Store and transmit genetic information


Ex: DNA and RNA
Made of nucleotides – repeating units made of PCHON
 Sugar, base, phosphate group



DNA and RNA- both have 4 types of nucleotides
DNA – double helix (2 chains, spiral); genetic material
RNA – one strand, makes proteins

Fill in the blanks:



KOH + HBr
HCl +

LiOH + HBr 
+ H
2
O
 KCl + H
2
O
+
 ______ + ______  RbF + H
2
O

ANSWERS!




KOH + HBr  KBr + H
2
O
HCl + KOH  KCl + H
2
O
LiOH + HBr  LiBr + H
2
O
HF + RbOH  RbF + H
2
O

DO NOW
 Draw the atomic structure and the
Lewis structure for magnesium (Mg).
Is magnesium stable? If not, what should it do to become stable?
 Fill in the blanks:
HF + LiOH  +

Energy, Work, and Order
 Energy = ability to do work or cause change
 Potential = stored energy
 Kinetic = energy of motion
 For work to occur, potential energy must be converted to kinetic energy

Energy in Cells
 Energy is used for many things in cells:
 Moving substances
 Building new molecules
 Growth
 Reproduction
 Establishing and maintaining order

Establishing/Maintaining Order
 Atoms/molecules arranged in specialized order
 Organization allows cells and systems to function properly
 EX: cells organized to tissues, organized into organs, and finally body systems.
 Takes ENERGY to maintain organization

Energy and Order
 Cells, atoms, etc, WANT to be in a state of disorder
 Without energy, systems become simple/disorganized (entropy)
 Continual input of energy keeps a state of order
 Organisms = highly organized systems b/c of constant energy input
 Where is the energy from?

Energy in Reactions
 Synthesis rxns use energy
 Often, they react very slowly
 Need catalysts
 Catalyst = substance that promotes chem rxns but is not affected/used up
 Enzyme = specialized catalyst in organisms.

Photosynthesis
 Process by which autotrophs (producers) like plants (and some bacteria and green algae) make their own food
 Uses water, carbon dioxide, and energy from sunlight to make glucose (sugar)
 Takes place if organism has chlorophyll
(green pigment)
 Usually happens in leaves

Photosynthesis cont.
 Synthesis reaction
 Requires energy in form of sunlight

Photosynthesis cont’d sunlight
Water + carbon dioxide  oxygen + glucose
6H
2
O + 6CO
2 sunlight
 6O
2
+ C
6
H
12
O
6
Glucose = sugar; stored as sugar to give plants energy, and starch to give consumers energy

Photosynthesis cont’d


Plants get water from roots, transported to leaves by xylem
Stomata – “doorways” into leaves for gases
 CO
2 in and O
2 out
 Gases cannot pass through waxy part of leaf
 Sunlight captured in chloroplasts in cells, which produce chlorophyll (pigmentabsorbs light)

Stomata

Chloroplast

Respiration
 Glucose  energy
 Decomposition reaction
 Occurs in mitochondria
 ALL organisms go through respirationsome aerobic, some anaerobic

Mitochondria: “the powerhouse”

Respiration cont’d
Glucose + oxygen  carbon + water + energy dioxide
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O + energy

Energy Molecules
 Energy stored in ATP as chemical energy
 ATP: adenosine triphosphate

ATP  ADP
 ADP: andenosine diphosphate
 Remains when ATP is used
 Cycle replaces ATP supply

3 Steps of Respiration
1.
2.
3.
Glycolysis
Krebs Cycle
Electron Transport System

Glycolysis (pg. 397)
 Glyco = sugar
 Lysis = to split apart
 Glucose split in half
 Net 2 ATP

Krebs cycle (pg. 399)
 3-carbon molecules disassembled
 Carbon dioxide released
 Energy released – gain of 2 ATP (4 total so far)
 Hydrogen also released  electron transport

Electron Transport Chain (pg. 400)

Hydrogen’s electrons transferred from carrier to carrier, releasing energy

“Caught” by oxygen – makes water
(released)
 34 ATP gain (38 total)
 44% energy from glucose  ATP
 Only 25% of gas in car  usable energy!

Oxygen/Carbon Dioxide Cycle
 Oxygen is a waste product of photosynthesis, but is used in respiration.
 Carbon dioxide is a waste product of respiration, but is used in photosynthesis.

Two Types of Chemical Rxns
Synthesis
 Compounds are made
 Energy is required/used
 Ex: Making glucose
(photosynthesis)
Decomposition
 Compounds are broken down
 Energy is released
 Ex: breaking down food
(digestion)

Synthesis or Decomposition?
Na + Cl  NaCl
NaCl  Na + Cl

Synthesis or Decomposition?
Na + Cl  NaCl synthesis
NaCl  Na + Cl decomposition

Ionization Reactions
 Ionic bonds can separate in solution
 Ex: salt in water separates to Na + and
Cl ions in the water


Compounds NOT made of ions can undergo ionization
Ex: water – not made of ions, but very few water molecules separate into ions


Important for many life functions
H
2
O  H + + OH -

H
2
O  H + + OH -
 H + = hydrogen ion (H lost an e-, and now it’s only a proton)
 OH = hydroxide ion (it has the e- lost by the hydrogen ion)
 Ionized water: hydrogen ions = hydroxide ions
 When hydrogen ions ≠ hydroxide ions, the solution is an acid or a base