Transcript Chemistry, Bonds, Phospholipids, triglycerides, proteins, ATP

Lecture 3 : How Matter is Organized
• Chemistry is the science of the
structure and interactions of matter.
– all living things consist of matter.
• Matter is anything that occupies space.
– mass is the amount of matter in any object.
– weight is the force of gravity acting on
matter.
• In outer space, weight is close to zero,
but mass remains the same as on
Earth.
Chemical Elements
• Elements are substances that can not be split into
simpler substances by ordinary means.
– 92 elements exist in nature
– 26 of naturally occurring elements are in the
body
– represented by chemical symbols ( first 1-2
letters of name )Na Natrium=Sodium
• 4 elements form 96 % of the body’s mass
– hydrogen, oxygen, carbon and nitrogen
• Trace elements are present in tiny amounts
– such as copper,selenium & zinc
Structure of Atoms
• Atoms are the smallest units of
matter that retain the properties of
an element
• Atoms consist of 3 types of
subatomic particles
– protons, neutrons and electrons
• Nucleus contains protons (p+) &
neutrons (neutral charge)
• Electrons (e-) surround the
nucleus as a cloud (electron shells
are designated regions of the
cloud)
Electron Shells
• Most likely region of the electron
cloud in which to find electrons
orbiting the nucleus
• Each electron shell can hold only
a limited number of electrons
– first shell can hold only 2 electrons
– 2nd shell can hold 8 electrons
– 3rd shell can hold 18 electrons
– higher shells (up to 7) hold many more electrons
• Number of electrons = number of protons
• Each atom is electrically neutral; charge = 0
Atomic Number & Mass Number
• Atomic number is number of protons in the nucleus.
• Mass number is the sum of its protons and neutrons.
Ions, Molecules, & Compounds
• Ions are formed by ionization
– an atom that gave up or gained an electron
– written with its chemical symbol and (+) or
(-)
• Molecule
– molecules = when 2 of the same atoms
share electrons
– compound = when 2 or more different
atoms share electrons
– written as molecular formula showing the
number of atoms of each element (H2O)
Chemical Bonds
• Bonds hold together the atoms in molecules and
compounds
• An atom with a full outer electron shell is
stable and unlikely to form a bond with another
atom
• Octet rule states that biologically important
elements interact to produce chemically stable
arrangements of 8 electrons in the valence
shell.
• Whether electrons are shared, lost or gained
determines the types of bonds formed
Free Radicals
• Atom with an unpaired electron in its outmost shell
• Unstable and highly reactive
• Can become stable
– by giving up electron
– taking one off another molecule (breaking apart important body
molecules)
Free Radicals & Your Health
• Produced in your body by absorption of
energy in ultraviolet light in sunlight, x-rays,
by breakdown of harmful substances, &
during normal metabolic reactions, fried
foods, smoking, drugs, exercise.
• Linked to many diseases -- cancer, diabetes,
Alzheimer, atherosclerosis and arthritis
• Damage may be slowed with antioxidants
such as vitamins C and E, selenium & betacarotene (precursor to vitamin A). Increased
serum thiol levels with spinal adjustments.
Atoms achieve stability by gaining,
losing or sharing electrons to fill
their outermost energy level. The
interaction often involves the
formation of chemical bonds which
hold the participating atoms
together once the reaction has
ended.
3 basic types of chemical bonds
1) Ionic
2) Covalent
3) Hydrogen
Bonds continued
• When chemical bonding occurs, the result is the creation
on NEW CHEMICAL ENTITIES called MOLECULES
and COMPOUNDS.
• Molecule refers to any chemical structure consisting of
atoms held together by a COVALENT BOND.
• Compound is any chemical substance made of atoms
or 2 or more elements regardless of the bond.
• Not all compounds consist of molecules. Salt (NaCl)
held together by ionic bond.
• Water=H2O is a compound. It contains 2 elements
Hydrogen and Oxygen held by covalent bond
Ionic Bonds
• Positively (cations) and negatively charged ions
(anions) attract each other to form an ionic bond
• Atoms become ions by losing or gaining electrons
• We assign + to charge on proton and - to charge on
electron.
• In the body, ionic bonds are found mainly in teeth and
bones
• An ionic compound that dissociates in water into + and ions is called an electrolyte( Na+Cl-)salt
The Ionic Bond in Sodium Chloride
• Sodium loses an electron
to become Na+ (cation)
• Chlorine gains an electron
to become Cl- (anion)
• Na+ and Cl- are attracted
to each other to form the
compound sodium chloride
(NaCl) -- table salt
• Ionic compounds generally
exist as solids
Covalent Bonds
• Some atoms can complete there outer shells not
by gaining or losing electrons but by SHARING.
• Individual Hydrogen atoms DON’T exist in
nature. Instead we find H molecules. Molecular
H consists of a PAIR of H atoms.
• In chemical shorthand Molecular hydrogen =
H2. H is symbol for Hydrogen and the subscript
2 indicates the number of atoms.
Covalent Bonds
• Atoms share electrons to
form covalent bonds
• Electrons spend most of
the time between the 2
atomic nuclei
– single bond = share 1pair
– double bone = share 2 pair
– triple bond = share 3 pair
• Polar covalent bonds
share electrons unequally
between the atoms
involved
Polar Covalent Bonds
• Unequal sharing of electrons between atoms.
• In a water molecule, oxygen attracts the hydrogen electrons
more strongly so the electrons spend more time orbiting the
oxygen nucleus than orbiting the hydrogen nucleus
– Oxygen has greater electronegativity as indicated by the
negative Greek delta sign.
Hydrogen Bonds
• Covalent & ionic bonds tie atoms together to form
molecules and compounds. Other WEAK forces also act
between adjacent molecules and even between atoms
within a large molecule. The MOST IMPORTANT OF
THESE WEAK ATTRACTIVE FORCES is the
HYDROGEN BOND.
• A HYDROGEN BOND is the attraction between + on the
HYDROGEN atom of a polar covalent bond and a – on
an oxygen or nitrogen atom of another polar covalent
bond.
• Hydrogen bonds are to weak to create molecules but
can change molecular shape. Surface tension( insects )
States of Matter
• Matter exists as either SOLID, LIQUID or GAS.
• Solids maintain their volume and their shape at
ordinary temperature and pressure.
• Liquids have a constant volume but no fixed
shape.
• Gas has neither a constant volume nor fixed
shape.
• WATER is the only substance that can exist
as ALL 3.
Lecture 4 BASIC ENERGY CONCEPTS
• To understand the relationship between MATTER and
ENERGY it’s essential to discuss chemical reactions.
• WORK- Movement of an object or change in the
physical structure of matter ( walking or running) (
converting water to water vapor)
• ENERGY- Capacity to perform work. Need energy to do
work.
• Kinetic energy- energy in motion. Falling off ladder, it’s
kinetic energy that does damage.
• Potential energy- stored energy that has potential to do
work.
• The potential energy in batteries is converted into kinetic
energy that vibrates sound producing membranes of
headset of I-POD.
Potential  Kinetic Energy
• Cells perform work as they synthesize complex
molecules into, out of, and within the cell.
• Cells of skeletal muscle at REST have potential
energy in the form of protein filaments and the
covalent bonds between molecules inside the
cells.
• When the muscle contracts it performs work.
Potential energy is converted into kinetic energy
and HEAT IS RELEASED.
• As a result when you exercise, your body
temperature rises.
Thermodynamic laws
• Energy can’t be created or destroyed
• Energy can only be converted from
one form to another.
• The conversion is never 100%
efficient. Each time energy exchange
occurs some energy is released into
non useable form.
TYPES of chemical reactions
• 3 types of chemical reactions.
• Decomposition
• Synthesis
• Reaction ( exchange/reversible )
Decomposition Reactions-Catabolism
• Large molecules are split into smaller
atoms, ions or molecules
• All decomposition reactions occurring
together in the body are known as
catabolism
• Usually are exergonic since they release
more energy than they absorb
Catabolism
• AB A + B
• When you eat a meal of Proteins, Fats, and
Sugars which are too complex to be absorbed,
decomposition reactions in the digestive tract
break down these molecules.
• Decomposition involving water is important in
breakdown of complex molecules. HYDROLYIS is
taking:
H20  H + OH
• When a covalent bond is broken, it releases
kinetic energy that can perform the work.
• When the energy is released cells perform vital
functions.
Synthesis Reactions--Anabolism
• Two or more atoms, ions or molecules combine
to form new & larger molecules
• All the synthesis reactions in the body together
are called anabolism
• Usually are endergonic because they absorb
more energy than they release
• Ex: The formation of water from hydrogen and
oxygen molecules.
• DEHYDRATION SYNTHESIS or condensation is
formation of a complex molecule by the
REMOVAL of WATER. The opposite of
hydrolysis.
Exchange Reactions
• Substances exchange atoms
– consist of both synthesis and decomposition
reactions
• Example
– HCl + NaHCO3  H2CO3 + NaCl
– ions have been exchanged between
substances
Reversible Reactions
• Chemical reactions can be reversible.
– Reactants can become products or products
can revert to the original reactants
• Indicated by the 2 arrows pointing in
opposite directions between the reactants
and the products
• AB
A + B
Reversible Reactions
• This is important with acid & bases to balance the pH.
• If you take carbonic acid and add OH then your left
with bicarbonate ( base).
H2CO3  HCO3
• If we take Bicarcbonate and add H then we end up
with carbonic acid.
HCO3  H2CO3
• Below is a type of response to pH in body fluids.
• C02 + H2O  H2CO3  HCO3 + H
•


Inorganic Compounds & Solvents
• Most of the chemicals in the body are
compounds
• Inorganic compounds
– usually lack carbon & hydrogen are
structurally simple
– water, carbon dioxide (a by-product of cell
metabolism), oxygen (important in metabolic
reaction,) acids, bases and salts
(compounds held together by IONIC BONDS )
• Organic compounds
– contain carbon & hydrogen
– always have covalent bonds
WATER PROPERTIES
• We will be concerned primarily with water
and how its properties are essential for
life. Most of the other inorganic
molecules exist in association with
water. Both carbon dioxide and oxygen for
example are gas molecules that are
transported in body fluids. All inorganic
acids, bases and salts dissolve in body
fluids as well. Water is known as the
universal SOLVENT
Water
• Water makes up about 2/3 of total body weight.
• The bonds in water are oriented in such a way that the
hydrogen atoms are close together. As a result the water
molecule has a (+) and (–) poles. Water is called
POLAR MOLECULE.
• Many inorganic compounds are held together by ionic
bonds. In water these COMPOUNDS undergo
IONIZATION = dissociation.
• Aqueous solution containing +/- ions will conduct
electrical current. + & - move toward each other.
• Many inorganic/organic molecules will dissolve in
water=solution. The medium in which other atoms, ions
molecules are dispersed is called the solvent. The
dispersed substances are the solute.
Water Functions
• Heat capacity is high. It can absorb a large amount of
heat with only a small increase in its own temperature.
• large number of hydrogen bonds in water
– bonds are broken as heat is absorbed instead of increasing
temperature of water.
• The cohesive nature of water molecules allows
blood and body fluids to flow smoothly through
vessels and tissue spaces and allows for uniform
distribution of solutes.
• Major component of lubricating fluids within the body
– mucus in respiratory and digestive systems
– synovial fluid in joints
– serous fluids in chest and abdominal cavities
• organs slide past one another
Electrolytes
• Soluble inorganic molecules whose ions
conduct an electrical current in solution are
electrolytes.
• NaCl is an electrolyte.
• Changes in the concentration of electrolytes in
body will effect every vital function. Ex:
decreased potassium levels will lead to general
muscular paralysis and increased levels will
cause weak or irregular hear beats.
• The balance (homeostasis) is regulated by
Kidneys ( ion excretion) the digestive tract
(ion absorption) and skeletal system
(ion storage or release)
Electrolytes
• + IONS (Cations)
•
•
•
•
•
Na
K
Ca
Mg
- Sodium
- Potassium
- Calcium
- Magnesium
- IONS (Anions)
Cl
HCO3 – Bicarbonate
HPO4 – Phosphate
SO4 – Sulfate
PROTEINS
• These are used in acid/base balance and action
potentials.
Hydrophilic & Hydrophobic Compounds
• Some organic molecules contain polar
covalent bonds which also attract water
molecules. The hydration spheres that
form may then carry these molecules into
SOLUTION.
• Molecules such as GLUCOSE ( an
important soluble sugar) that interact
readily with water is called
HYDROPHILIC. (Water- Loving)
Hydrophobic
• When organic molecules lack polar
covalent bonds or have few. These
molecules don’t have + or – terminals and
are said to be non polar.
• The most familiar hydrophobic
molecule are fats and oils of all kinds.
• Think of what happens if you spill gasoline
or oil in ocean. They form slicks instead of
dissolving.
Inorganic Acids, Bases & Salts
• Acids, bases and salts always dissociate into ions if they are
dissolved in water
– acids dissociate into H+
and one or more anions
– bases dissociate into OHand one or more cations
– salts dissociate into anions
and cations, none of which
are either H+ or OH• Acid & bases react in the body to form salts
• Electrolytes are important salts in the body that carry electric
current (in nerve or muscle)
ACID and BASES
• The human body can only remain healthy if it’s fluids
exist within a narrow band of pH. The pH scale
measures the relative concentration of HYDROGEN H+
and HYDROXIDE OH-.
• The pH scale goes from 0-14
• 0-6.9 is ACID: stomach HCL, beer, wine, tomatoes saliva
( contains more Hydrogen than Hydroxide)
• pH of 7 = neutral ( equal # of Hydrogen & Hydroxide)
• pH above 7 = Base ( more Hydroxide than Hydrogen)
blood, ocean water, bleach, ammonia (7.35-7.45 blood)
Should eat more alkaline FORMING foods to remain
healthier. Diet should have little acid forming foods.
80% alkaline foods and 20% acidic foods
Acid/ Base
• The strength of acid/base is determined by the ability of
the substances to dissociate into individual ions.
• HCL( hydrochloric acid) ( muriatic acid)  H+ Cl• Can lower the pH of pools
• NaOH (sodium hydroxide) Strong base----- Na+ + OH• Strong bases have industrial uses like drano.
• If acid or base is swallowed the UNIVERSAL ANTIDOTE
is RAW EGG WHITES, WATER & MILK. Then take to
hospital for further evaluation. Never vomit the acids up.
You will damage the tissues a second time.
Buffer Systems of the Body
• Body fluids vary in pH but the range of each is limited and is
maintained by a variety of buffering systems.
– gastric juice 1.2 to 3.0; saliva 6.35 to 6.85; bile 7.6 to 8.6
and blood 7.35 to 7.45
• Buffers stabilize the pH of a solution by removing or
replacing hydrogen ions. They involve a WEAK ACID and
its related salt.
– carbonic acid - bicarbonate buffer system NaHCO3
otherwise known as baking soda. Alka-Seltzer can
neutralize the acid in the stomach.
– HCL + NaOH - H2O + NaCl
– This reaction produces water and salt. By adding HCL you
neutralize both the strong acid and strong base.
Carbonic Acid Bicarbonate Buffering System
• Carbonic Acid H2CO3
• Bicarbonate
HCO3
• If you add H which is an ACID it will go to the BASE to
make it less basic or more acidic. If there is HCO3 in a
flask of water and you add H, the result is H2CO3
•
• HCO  H2CO
ADD H
3
•
ADD OH
• H2CO3  HCO3
3
A base became an acid
A acid became a base
Lecture 5 -Organic Compounds
• Always contain carbon and
hydrogen & generally Oxygen
• Usually long chain of Carbon atoms
linked by covalent bonds
• The carbon atoms typically form
additional bonds with Hydrogen or
Oxygen.
• Make up 40% of body mass.
• 4 Main Classes: Carbs, Lipids,
Proteins, and Nucleic Acids.
Functional groups of Organic Compounds
• Carboxyl Group –COOH : Acts as an acid, releasing H
bonds to become R…--COO - Examples are Fatty
acids and Amino Acids
• Amino Group –NH2 Can accept or release H bonds
depending on the pH. An example are Amino acids
• Hydroxyl Group –OH Strong base dissociate to release
hydroxide ions ( OH-) Examples Carbohydrates, amino
acids, and fatty acids.
• Phosphate Group –PO4 Links other molecules to form
larger structures. Stores energy in high NRG bonds.
Example: phospholipids, nucleic acids.
Isomers
• Isomers have same molecular formulas but
different structures (glucose & fructose are both
C6H12O6
• STRUCTURAL
FORMULA OF
GLUCOSE
Carbohydrates
• Sugars and Starches that make up
roughly ½ of U.S. diet.
• Important for energy sources that are
catabolized rather than stored.
• 3 sizes of carbohydrate molecules
– monosaccharides
– disaccharides
– polysaccharides
Carbohydrates
• Diverse group of substances formed from C, H, and O
– ratio of one carbon atom for each water molecule
(carbohydrates means “watered carbon”)
– glucose is 6 carbon atoms and 6 water molecules
(H20)
• Main function is source of energy for ATP formation
• Forms only 1 % of total body weight
– glycogen is storage form of glucose in liver and
muscle tissue
– sugar building blocks of DNA & RNA
(deoxyribose & ribose sugars)
C6H12O6 - Glucose
Monosaccharides
• Called simple sugars
• Contain 3 to 7 carbon atoms
• We can absorb only 3 simple sugars
without further digestion in our small
intestine
– glucose found in syrup or honey
(metabolic fuel)
– fructose found in fruit
– galactose found in dairy products
Disaccharides
• Formed by combining 2 monosaccharides by dehydration synthesis
(releases a water molecule)
– sucrose (table sugar)= glucose & fructose
– Maltose(beer) = glucose & glucose
– Lactose(dairy) = glucose & galactose (lactose intolerance)
– ALL carbs except monosaccharides need to be broken down by
hydrolysis before they can provide useful energy.
– Sugars are stored as fat for energy. ( artificial sweeteners can’t be
broken down)
Polysaccharides- 3 Complex Carbohydrates
• Contain 10 or 100’s of monosaccharides joined by
dehydration synthesis.
• STARCH: The storage form of glucose in plants. High
concentrations of glucose in plant or animal cells is
TOXIC. Surplus stores of glucose is converted to starch
for safety.
• Glycogen is the storage form of glucose in animals.
Glycogen is stored in the liver (hepatocytes) and in muscle
cells. If serum glucose levels fall, glycogen is converted
into glucose
• Cellulose: can only digest small amounts via bacterial
action. Cellulose is called dietary fiber. Water soluble
found in fruits veggies. LOWER CHOLESTEROL.
Insoluble fiber is in nuts and grains.
Lipids = fats
• Formed from C, H and O
– includes Fats, oils, waxes,
• 18-25% of body weight
• Hydrophobic
– insoluble in polar solvents like water
• BUT can combines with proteins for transport in blood
(lipoproteins LDL’s, HDL’s )
• They form the essential structural component of all cells.
• They provide twice the energy as carbs gram for gram when
broken down in the body.
• 5 Classes: Fatty acids, eicosanoids, glycerides, steroids,
phospholipids.
Fatty Acids
• Fatty acids is a long Carbon chain with a
carboxylic group at the end
• C—C—C—C—COOH
• Carboxyl tells us the Carbon and a
hydroxyl (-OH) group are the important
structural features of fatty acids.
• Lauric Acid found in coconut oil.
• They can be saturated or unsaturated.
Triglycerides
• Neutral fats composed of a single glycerol molecule
and 3 fatty acid molecules
– three-carbon glycerol molecule is the backbone
• Very concentrated form of energy
– 9 calories/gram compared to 4 for proteins &
carbohydrates
– our bodies store triglycerides in fat cells if we eat
extra food. Major source of stored energy in the
body.
– Fatty Acids help make up Triglycerides in 2
forms. SATURATED & UNSATURATED.
Triglycerides
• 3 fatty acids & one glycerol molecule
• Fatty acids attached by dehydration systhesis
Triglycerides continued
• Saturated fatty acids are found in animal products and are
solid at room temperature and linked to cardiovascular
dis-ease.
• Unsaturated Fatty Acids are liquids at room
temperature and found in plants. When good unsaturated
fatty acids are heated as in deep frying, oxidation of fatty
acids occurs.
( olive oil, peanut oil )
• Margarine is made of corn oil a polyunsaturated fatty acid.
Corn oil is hydrogenated by bubbling hydrogen gas through
it. Hydrogenating polyunsaturated fats produces trans fats
which are harmful to the body.
Oils & Waxes
• Oils are very similar to polyunsaturated
fatty acids. Oils are lipids that are
liquids at room temperature. Oils we
produce act as natural sun block, barrier
to bacteria and lubricant for skin.
• Waxes- Are lipids that are solid at room
temperature. Produced to protect dust
particles form entering the external canal.
Lecture 6 Phospholipids
• Consists of a lipid molecule joined to a
phosphate.
• They act as the structural component of
the cell and are used by the body to
emulsify fats.
• They have a phosphate group --PO4 ( hydrophilic end )
• They have a lipid ( Fatty Acids) ( hydrophobic end)
Phospholipids
• Composition of phospholipid molecule
– a polar head
• a phosphate group (PO4-3) & glycerol molecule
• can form hydrogen bonds with water
– 2 nonpolar fatty acid tails
• interact only with lipids
• Composition of cell membrane
– double layer of phospholipids with tails in
center
– Participates in transport of lipids in plasma
Chemical Nature of Phospholipids
head
tails
Steroids
• Cholesterol- structural basis of all body steroids. We
ingest it form eggs, milk, cheese, and our liver makes
80% of what we need.
• Bile salts-these breakdown products of cholesterol are
released by the liver into the digestive tract, where they
aid in fat digestion and absorption.
• Vitamin D- A fat soluble vitamin produced in the skin on
exposure to UV radiation. Needed for bone growth and
calcium absorption, and immune function.
• Sex hormones- Estrogen and progesterone(female) and
Testosterone(male). Needed for normal sexual function
• Adrenocorticol hormones- Cortisol a glucocorticoid is a
metabolic hormone needed to maintain blood glucose
levels. Aldosterone regulates salt and water balance by
Fat Soluble vitamins
• A- ingested in orange pigmented vegetables
and fruits. Converted in the retina to retinal. Part
of vision. Also used to heal epithelial
membranes.
• E- Ingested in plant products like wheat germ
and green leafy vegetables. Wound healing,
fertility, neutralizes free radicals, anticancer.
• K- Made available by humans largely by action
of intestinal bacteria. Needed for blood clotting.
• Co-Enzyme Q10(COQ10) not a vitamin- Needed
by the mitochondria for the Electron Transport
Chain (ETC) for ATP production. Muscles need
Steroids
• All animal cells membranes contain cholesterol.
• HDL/LDL- Statin Drugs/Liver/Nerves/Depression
• It’s obtained by absorption from animal products
or made within the body. Limit intake to under
300mg a day.
Four Ring Structure of Steroids
Eicosanoids
• Lipid type derived from a fatty acid called
arachidonic acid
– prostaglandins = wide variety of functions and
can be blocked by NSAIDS or COX inhibitors.
•
•
•
•
•
•
•
Regulates blood pressure
Uterine contractions
contribute to inflammatory response
prevent stomach ulcers
dilate airways
regulate body temperature
influence formation of blood clots
– leukotrienes = allergy & inflammatory responses
Proteins
• The most abundant organic component of the body.
• Functions consist of:
• Support- Structural proteins: framework of the body
providing strength. Collagen, keratin, elastin
• Movement- Contractile proteins needed for muscle
contraction. Actin any Myosin.
• Transport proteins- Hemoglobin transports oxygen in
blood. Lipoproteins transport lipids and cholesterol.
• Buffering- Assist in pH changes. Albumin acts as acid
and base to prevent wide swing in Ph.
• Catalysis-ENZYMES accelerate chemical reactions in
cells.
• Regulation of metabolism- growth hormone, insulin.
Protein function continued
• Defense- Tough waterproof proteins of the
skin, hair, nails protect the body from
hazards. Proteins called antibodies are
components of the immune system, helps
protect us from foreign matter. Special
clotting proteins restrict bleeding after an
injury to the cardiovascular system.
Proteins
• 12-20% of body weight
• Contain carbon, hydrogen, oxygen, and nitrogen
• Constructed from combinations of 20 amino acids.
– dipeptides formed from 2 amino acids joined by a
covalent bond called a peptide bond
– polypeptides chains formed from 10 to 2000 amino
acids.
• Levels of structural organization
– primary, secondary and tertiary
– shape of the protein influences its ability to form bonds
Amino Acid Structure
• Central carbon atom
• Amino group (NH2)
• Carboxyl group
(COOH)
• Side chains (R
groups) vary between
amino acids
Formation of a Dipeptide Bond
• Dipeptides formed from 2 amino acids joined by a
covalent bond called a peptide bond
– dehydration synthesis
• Polypeptides chains formed from 10 to 2000 amino
acids.
Enzymes
• Enzymes are protein molecules that act as
catalysts
• Enzymes usually end in suffix -ase and are
named for the types of chemical reactions they
catalyze
• Steak in dish of water at 100 degrees could take
months to fully breakdown. BUT in digestive tract,
it only takes hours b/c of digestive ENZYMES.
• Cofactor- An ion or molecule that must bind to the
enzyme for reaction to occur. (Ca, Mg, Zn)
Enzyme Functionality
• Acts on only one substrate
• Lipases work only on lipids
– speed up only one reaction
• Very efficient
– speed up reaction up to 10
billion times faster.
– Enzymes are globular
proteins that contain specific
areas called ACTIVE SITE.
The active site will bond with
the substrate.
– Induced fit ( lock and key
model)
Nucleic Acids - DNA & RNA
• Huge molecules containing
C, H, O, N and phosphorus
• Each gene of our genetic
material is a piece of DNA
that controls the synthesis
of a specific protein
• A molecule of DNA is a
chain of nucleotides
• Nucleotide = 1)nitrogenous
base (A-G-T-C) + 2)pentose
sugar + 3)phosphate group
• This is DNA- Double Helix
•
Main function is storage & transfer
of info essential for synthesis of
proteins.
DNA
• DeoxyriboNucleic Acid- DNA determines
our characteristics of eye color, hair color,
blood type.
• It affects aspects of body structure and
function b/c DNA ENCODES the info
needed to build proteins.
• Used to identify criminal, victim or a child’s
parents
– need only strand of hair, drop of semen or
spot of blood
Main Nitrogenous Bases
•
•
•
•
•
•
A=Adenine
G=Guanine
C=Cytosine
T=Thymine
Purines are Adenine & Guanine Double ringed
Pyramidines Cytosine & Thymine Single ringed
RNA Structure
• Differs from DNA
– single stranded
– ribose sugar not deoxyribose sugar
– uracil nitrogenous base replaces
thymine
• Types of RNA within the cell, each with a
specific function. Performs protein synthesis
– messenger RNA- transcription
– ribosomal RNA
– transfer RNA-translation
High energy compounds
• To perform their vital functions, cells must use
energy, obtained from breaking down organic
substrates via catabolism.
• A high energy bond is a covalent bond whose
breakdown releases the energy the cell can use.
• In our cells, a high NRG compound connects a
phosphate group PO4 to an organic molecule.
This is called PHOSPHORYLATION.
• AMPADPATP
Adenosine Triphosphate (ATP) High energy compound
• ATP is needed for: muscle contraction,
transport of substances across cell
membranes, movement of structures within
cells and movement of organelles
• Consists of 3 phosphate
groups attached to
adenine & 5-carbon
sugar (ribose)
Formation & Usage of ATP
• Hydrolysis of ATP (removal of terminal
phosphate group by enzyme -- ATPase)
– releases energy
– leaves ADP (adenosine diphosphate)
• Synthesis of ATP
– enzyme ATP synthase catalyzes the
addition of the terminal phosphate
group to ADP
– energy from 1 glucose molecule is used
during both anaerobic and aerobic
respiration to create 36 to 38 molecules of
ATP