Water and Solutions

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=HVT3Y3_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 dropletsAllows insects to rest on water’s surface

Adhesive Water forms H-

bonds 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 throughoutEx: salt water, soda

Heterogeneous – mixture is different throughoutEx: salad, salad dressing

Solutions

Homogenous mixture Molecules of one substance mix

evenly w/those of another (dissolves) 2 parts:

Solute – substance that is dissolvedSolvent – substance that does the

dissolvingName 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

6.4: The Building Blocks of Life

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 1:2:1Ex: glucose = C6H12O6

Reduces to 1:2:1 (CH2O)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 togetherChain 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 PCHONSugar, 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 + H2O

HCl + KCl + H2O LiOH + HBr + ______ + ______ RbF + H2O

ANSWERS!

KOH + HBr KBr + H2O

HCl + KOH KCl + H2O

LiOH + HBr LiBr + H2O

HF + RbOH RbF + H2O

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 substancesBuilding new moleculesGrowth Reproduction Establishing and maintaining order

Establishing/Maintaining Order

Atoms/molecules arranged in specialized order

Organization allows cells and systems to function properlyEX: 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

sunlight

6H2O + 6CO2 6O2 + C6H12O6

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 gasesCO2 in and O2 outGases cannot pass through waxy part of leaf

Sunlight captured in chloroplasts in cells, which produce chlorophyll (pigment-absorbs light)

Stomata

Chloroplast

Respiration

Glucose energy Decomposition reaction Occurs in mitochondria ALL organisms go through respiration-

some aerobic, some anaerobic

Mitochondria: “the powerhouse”

Respiration cont’d

Glucose + oxygen carbon + water + energy

dioxide

C6H12O6 + 6O2 6CO2 + 6H2O + 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. Glycolysis

2. Krebs Cycle

3. 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 H2O H+ + OH-

H2O 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