Transcript Properties of Water & Macromolecules

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=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
of water – attracted to each
other b/c of H-bonds
 Causes surface tension
 Molecules
 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
– mixture looks the
same throughout
Ex: salt water, soda
 Heterogeneous – mixture is different
throughout
Ex: salad, salad dressing
 Homogeneous
Solutions
 Homogenous
mixture
 Molecules of one substance mix
evenly w/those of another (dissolves)
 2 parts:
– substance that is dissolved
Solvent – substance that does the
dissolving
Name solute & solvent in salt water
Solute
Concentrations of solutions
– less solute
 Concentrated – more solute
 Saturated – solution has as much solute
as it can hold.
 Dilute
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
Bases
 release hydrogen  release hydroxide
ions (H+) when
ions(OH-) when
dissolved in water
dissolved in water
 Ex: stomach acid,  Ex: ammonia,
vinegar, citrus
soap, blood
fruit
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
1:2:1
Ex:
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
of amino acids – small carbon
compounds made of CHONS
(carbon, hydrogen, oxygen, nitrogen,
sometimes sulfur)
 20 different amino acids
 Made
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
structure – number and order
of amino acids joined together
 Primary
Chain
of amino acids = polypeptide
structure – chain folds into
a 3-D shape: helix or pleat
 Secondary
Protein Structure
What are proteins for?
– 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)
 Enzymes
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 
+ H 2O
 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 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
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
gases

 CO2 in
and O2 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
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.
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
 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