Transcript Types of Organic compounds

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
– Does air have matter?
Chemical Elements
• Elements are substances that can not be split
into simpler substances by ordinary means.
– 112 elements ( 92 occur naturally )
– 26 of naturally occurring elements are in the body
– represented by chemical symbols ( first 1-2 letters
of name )
• 4 elements form 96 % of the body’s mass
– hydrogen, oxygen, carbon and nitrogen
• Trace elements are present in tiny amounts
– such as copper, tin, 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)
Atomic Number & Mass Number
• Atomic number is number of protons in the nucleus. .
• Mass number is the sum of its protons and neutrons.
Isotopes
Molecule, Element, compound
• Molecule= more than one atom existing in union
• Element= Molecule contains identical atoms
• Compound: Molecule contains different atoms
IONS: Charged particles
When an atom gains or loses electrons ions are
formed
Positively charged= cation
Negatively charged = anion
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
• Linked to many diseases -- cancer, diabetes, Alzheimer,
atherosclerosis and arthritis
• Damage may be slowed with antioxidants such as vitamins C
and E, selenium & beta-carotene (precursor to vitamin A)
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, donated or acquired
determines the types of
bonds formed
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 bond = share 2 pair
– triple bond = share 3 pair
Polar Covalent Bonds
• Unequal sharing of electrons between atoms.
• In a water molecule, oxygen attracts the
hydrogen electrons more strongly
– Oxygen has greater electronegativity as
indicated by the negative Greek delta sign.
Ionic Bonds
• Positively and negatively
charged ions attract each
other to form an ionic bond
• 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
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
Hydrogen bonds
• Hydrogen bonds are the most important inter
molecular force of attraction .
• Formed by the attraction between slightly positive
Hydrogen atom and a slightly negative atom of
another element.
• Too weak to create molecules but creates shapes
and stabilizes large molecules like proteins or
nucleic acids
Chemical Reactions
• When new bonds form or old bonds are broken
• Metabolism is all the chemical reactions in the body
Energy and Chemical Reactions
• Chemical reactions involve energy changes
• Law of conservation of energy
– energy can neither be created nor destroyed--just
converted from one form to another
• Reactions that yield energy = Exergonic reactions
(Larger to smaller molecules)
AB  A + B
• Reactions that require energy to occur= Endergonic
reactions (smaller to larger molecules )
A + B AB
Energy Transfer in Chemical
Reactions
• Chemical reactions usually involve
both
• Human metabolism couples
exergonic and endergonic
reactions, so that the energy
released from one reaction will
drive the other.
– Glucose breakdown releases energy
used to build ATP molecules that
store that energy for later use in
other reactions
Activation Energy
• Atoms, ions & molecules
are continuously moving
& colliding
• Activation energy is the
collision energy needed
to break bonds & begin a
reaction
• Increases in concentration & temperature, increase the
probability of 2 particles colliding
– more particles in a given space as concentration is raised
– particles move more rapidly when temperature is raised
Catalysts/Enzymes
• Normal body temperatures
and concentrations are too
low to cause chemical
reactions to occur
• Catalysts speed up chemical
reactions by lowering the
activation energy needed to
get it started
• Catalysts orient the
colliding particles properly
so that they touch at the
spots that make the
reaction happen
• Catalyst molecules are
unchanged and can be used
repeatedly to speed up
similar reactions.
Free Energy and
Activation
Energy Tutorial
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
• Example
– combining amino acids to
form a protein molecule
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
Inorganic Compounds & Solvents
• Most of the chemicals in the body are
compounds
• Inorganic compounds
– usually lack carbon & are structurally simple
– water, salts, acids and bases
• Organic compounds
– contain carbon & usually hydrogen
– always have covalent bonds
Dissociation
pH - measure or acidity/alkalinity pH = - log [H+]
acidic < 7 < basic
Acids-raise H+ content
Bases-lower H+ content:
release OH- or accepts H+
1pH unit = 10x difference
1000 as many H+ in a pH of 5 as there are in 8
Buffer-takes up or releases H+ or OH- to prevent
changes in pH. In the bicarbonate system, H2CO3 H+
base acceptor, HCO3- acid acceptor
What happens to shells in carbonated drinks?
Does Sea Ice Speed Up Ocean Acidification?
How does the bicarbonate system work in a blood plasma? In the ocean?
Ocean Acidification: 2, 3
Carbon dioxide
concentration in
metabolically active cells is
much greater than in
capillaries, so carbon
dioxide diffuses from the
cells into the capillaries.
About 7% of the CO2
directly dissolves in the
plasma. Another 23% binds
to the amino groups in
hemoglobin. The remaining
70% is transported in the
blood as bicarbonate ion.
Concept of pH
• pH scale runs from 0 to
14 (concentration of H+
in soln.)
• pH of 7 is neutral
(distilled water)
• pH below 7 is acidic and
above 7 is alkaline
• What is more acid than lemon?
• In a test of pH levels, a glass of milk was found to have a pH of 6.0. A
glass of grape juice had a pH of 3.0. What is the relationship between
the pH levels of the milk and grape juice?
A The milk is 100 times more acidic than the grape juice
B The grape juice is 3 times more acidic than the milk
C The milk is 3 times more acidic than the grape juice
D The grape juice is 1000 times more acidic than the milk
• How many more H+’s do tomatoes have than bananas? Lemons than milk?
Bleach than soap?
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)
Water & It’s Properties
• Most important inorganic compound in living
systems, Medium of nearly all chemical reactions
• Polarity
– uneven sharing of electrons
• makes it an excellent solvent for ionic or polar substances
• gives water molecules cohesion
• allows water to moderate temperature changes
• Participates as a product or reactant in certain
reactions in the body
– hydrolysis reactions
• water is added to a large molecule to separate it into
two smaller molecules
• digestion of food
– dehydration synthesis reaction
• two small molecules are joined to form a larger
molecule releasing a water molecule
Water as a Solvent
• Most versatile solvent known
– polar covalent bonds (hydrophilic vs hydrophobic)
– its shape allows each water molecule to interact
with neighboring ions/molecules
• Water dissolves many substances
Water has a high surface tension
• Water is wet
• Water is attracted to itself, and this attraction,
due to H bonds is stronger than the attraction to
the air above
• Adhesion and cohesion allow for capillary action
water transport in plants
• Occurs as solid, liquid and gas within normal
temperature ranges on Earth
Water = good evaporative coolant
• Heat of vaporization is also high
– amount of heat needed to change from liquid to gas
– evaporation of water from the skin removes large amount of
heat
• B/c it takes a lot of energy to change water from a liquid to
a gas, it takes energy with it
• Heat capacity is high
– 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
– large amount of water in body helps lessen the impact of
environmental changes in temperature
Water as a Lubricant
• 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
Ice floats
• Water has a high freezing point and lower density
as a solid than a liquid
Chemical Reactions
• energy causes rearrangement of e-'s and new bonds, new
compounds are formed, E can be force of collision, heat,
electricity etc.
• reactants yield product(s)
• Balanced equations (energy cannot be created or
destroyed). Balance the following equations:
CH4 + O2  CO2 + H2O
CuO + NH3  Cu + H2O + N2
NH3 + O2  NO + H2O
CH4 + 2O2 = CO2 + 2H2O
3CuO + 2NH3 = 3Cu + 3H2O + N2
4NH3 + 5O2 = 4NO + 6H2O
• Mixtures-- combination of substances in
which the individual components retain
their own properties
• solutions-- or
more
substances
is
distributed evenly in another substance
solution=solvent(H2O)+solute(dissolvedparticles)
• suspension-- particles of materials
temporarily mixed together (blood)
• colloid-- particles larger than solution,
smaller than suspension (cytosol)
are
Chemistry Tutorial
• The Biology Project:
http://www.biology.arizona.edu/biochemistry
/tutorials/chemistry/main.html
Carbon & Its Functional Groups
• Properties of carbon atoms
– forms bonds with other carbon atoms produce large,
stable molecules
• with many different shapes (rings, straight or
branched chains)
• Many functional groups can attach to carbon skeleton
– esters, amino, carboxyl, phosphate groups (Table 2.5)
• Very large molecules called macromolecules (polymers if all
monomer subunits are similar)
• The properties of different biological molecules
depend on certain characteristic groupings of
atoms called functional groups.
• If you know the properties of some of the
functional groups, you will be able to quickly look
at many simple biological molecules and get some
idea of their solubility and possible identity. The
names of the six most important functional groups
are:
• Hydroxyl
• Carbonyl
• Carboxyl
• Amino
• Sulfhydryl
• Phosphate
Hydroxyl
• Two functional groups containing oxygen, the
hydroxyl and carbonyl groups, contribute to
water solubility.
• Hydroxyl groups have one hydrogen paired
with one oxygen atom (symbolized as -OH).
Hydroxyl groups are not highly reactive, but
they readily form hydrogen bonds and
contribute to making molecules soluble in
water. Alcohols and sugars are "loaded" with
hydroxyl groups.
Genistein and daidzein, two phytoestrogens from legumes
Notice that the only difference between these two molecules
is the additional hydroxyl (-OH) group on genistein. Both
are typical isoflavones. Genistein, however, is considerably
more estrogenic than daidzein; chemists attribute this to
the influence of the additional hydroxyl group. The hydroxyl
groups are important for binding to estrogen receptors.
Carbonyl
• Carbonyl groups have one oxygen atom doublebonded to a carbon atom (symbolized as -C=O).
Like hydroxyl groups, carbonyl groups contribute
to making molecules water-soluble. All sugar
molecules have one carbonyl group, in addition to
hydroxyl groups on the other carbon atoms.
– Aldehyde groups, where the C=O group is at the end of
an organic molecule. A hydrogen atom is also located on
the same carbon atom.
– Keto groups, where the C=O group is located within an
organic molecule. All sugars have either a keto or an
aldehyde group.
• Carbonyl
-COH
C3H6O
aldehyde =
end (propanol)
ketone =
inside (acetone)
Carboxylic Acids
• Carboxyl groups are weak acids, dissociating
partially to release hydrogen ions.The carboxyl
group (symbolized as COOH) has both a carbonyl
and a hydroxyl group attached to the same carbon
atom, resulting in new properties.
Carboxyl groups frequently ionize, releasing the H from the
hydroxyl group as a free proton (H+), with the remaining O
carrying a negative charge. Molecules containing carboxyl
groups are called carboxylic acids and dissociate partially
into H+ and COO–.
Carboxyl groups are common in many biological molecules,
including amino acids and fatty acids.
Amino Group
• Nitrogen in biological molecules usually occurs in
the form of basic amino groups.Nitrogen is
another abundant element in biological molecules.
Having a valence of 3, nitrogen normally forms
three covalent bonds, either single, double, or
triple bonds.
Amino groups (-NH2) are common functional groups
containing nitrogen. Amino groups are basic, and
often become ionized by the addition of a hydrogen
ion (H+), forming positively charged amino groups (NH3+).
Sulfhydryl
• Sulfur is found mainly in proteins in the form of
sulfhydryl groups or disulfide groups.Like oxygen,
sulfur typically has a valence of 2, although it can
also have a valence of 6, as in sulfuric acid.
Sulfur is found in certain amino acids and proteins
in the form of sulfhydryl groups (symbolized as SH). Two sulfhydryl groups can interact to form a
disulfide group (symbolized as -S-S-).
Phosphate Groups
• In biological molecules, phosphorus occurs mainly
in the form of acidic phosphate groups.
• Phosphorus normally has a valence of 5. Its most
common functional group in organic molecules is as a
phosphate group (symbolized as –OPO32-).
Phosphorus is covalently paired to 4 oxygen atoms
in phosphate groups: one P=O bond and three P-Obonds.
Importance of Functional Groups in
Biology
Function Groups Practice
Match the columns
1.
2.
3.
4.
5.
6.
Types of Organic compounds
Four major groups of organic
compounds, necessary for life are:
polymers
monomers____
– Carbohydrates
monosacchrides
– Lipids
fatty acids
– Proteins
amino acids
– Nucleic acids
nucleotides
Carbohydrates
• Diverse group of substances 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 to produce energy
• 3 sizes of carbohydrate molecules
– monosaccharides
– disaccharides
– polysaccharides
Mono saccharides
“one sugar”
•
•
•
•
Called simple sugars
Contain 3 to 7 carbon atoms
(CH2O)n
We can absorb only 3 simple sugars
without further digestion in our small
intestine
– glucose found in syrup or honey
– fructose found in fruit
– galactose found in dairy products
Disaccharides (“two”)
• Formed by combining 2 monosaccharides by
dehydration synthesis (releases a water molecule)
• Name of bond= Glycosidic bond
– sucrose = glucose & fructose
Condensation Rxn & Dehydration
Synthesis
• 2 Condensation & Hydrolysis QT Mov
Disacchrides of distinction
glucose + fructose = sucrose
glucose + glucose = maltose
glucose + galactose = lactose
Polysaccharides
• > 100’s of monomers by
dehydration synthesis
• In animals
– Glycogen: glucose
polymer, found in liver &
skeletal muscle, when
blood sugar level drops,
liver hydrolyzes glycogen
to create and release
glucose into the blood
(“many”)
Polysaccharide
Lipids = fats, oils, steroids, waxes
• Formed from C, H and O
• 18-25% of body weight
• Hydrophobic
– fewer polar bonds because of fewer oxygen atoms
– insoluble in water
• Combines with proteins for transport in blood
– Lipoproteins
• Three functional classes:
Storage lipid:
-Triglycerides: Common body fat.
Regulatory lipid:
- Steroids: act as hormone
- Eicosanoids: hormones
Structural lipid:
– Phospholipids: Cell membrane
– Glycolipids: Cell membrane
Triglycerides
• 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
Triglyceride Formation
• Triglycerides =
three fatty
acids attached
by dehydration
synthesis to
one molecule of
glycerol by an
ester bond
Figure 2.15
Saturation of Triglycerides
• Determined by the
number of single or
double covalent bonds
in fatty acid
• Saturated fats contain
single covalent bonds
and are covered with
hydrogen atoms----lard
• Unsaturated are not
completely covered
with hydrogen---safflower oil, corn oil
• Polyunsaturated fats
contain even less
hydrogen atoms----olive
and peanut oil
Regulatory lipids: Steroids
• Formed from 4 rings of
carbon atoms joined
together
• Common steroids
– sex hormones, bile salts,
vitamins & cholesterol
• Cholesterol found in animal
cell membranes
– starting material for
synthesis of other
steroids
Which is most soluble in
water?
Eicosanoids
• Lipid type derived from a fatty
acid called arachidonic acid
– prostaglandins = wide variety of
functions
•
•
•
•
•
•
modify responses to hormones
contribute to inflammatory response
prevent stomach ulcers
dilate airways
regulate body temperature
influence formation of blood clots
– leukotrienes = allergy &
inflammatory responses
Structural lipids
Phospholipids: Glycerol+ fatty acids + phosphate
Part of cell membrane. Ex. Lecithin.
Glycolipid: Glycerol+ fatty acid+ sugar chain.
Part of cell membrane surface.
Chemical Nature of Phospholipids
amphi pathic
head
tails
Lipid Behavior in Various
Environments
How do phospholipids behave
• In an oil spill?
• Submerged in water?
• In a living cell?
Lipoproteins
• What
determines
the density
of
lipoproteins?
Nucleic acids are chains of nucleotides
• Three types: DNA, RNA, ATP
• Function: Storage of genetic
information and energy
• Nucleotides are composed of:
sugar, phosphate,nitrogenous base
–
–
–
–
Sugar = deoxyribose (DNA) or ribose (RNA & ATP)
DNA Bases = adenine, thymine, cytosine, guanine
RNA bases = adenine, uracil, cytosine, guanine
Base Pairing: A-T, G-C or A-U. Held together by
hydrogen bonds
DNA Structure
• 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 = nitrogenous
base (A-G-T-C) + pentose
sugar + phosphate group
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
– messenger RNA
– ribosomal RNA
– transfer RNA
Adenosine Triphosphate (ATP)
• Temporary molecular storage of energy as it is
being transferred from exergonic catabolic
reactions to cellular activities
– 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
aerobic respiration to create 36 to 38 molecules
of ATP
Amino Acid Structure
•Central carbon atom
•Amino group (NH2)
•Carboxyl group (COOH)
•Hydrogen
•Side chains (R groups) vary between amino acids
Proteins
• Contain carbon, hydrogen, oxygen, and
nitrogen
• Constructed from combinations of 20
amino acids.
• Levels of structural organization
– primary, secondary and tertiary
– shape of the protein influences its ability to form
bonds
Which Amino Acids
are hydrophobic?
How do you know?
Which Amino
Acids are
alkaline?
Why?
Formation of a peptide 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.
Levels of Structural Organization
•
•
•
•
Primary is unique sequence of amino acids
Secondary is alpha helix or pleated sheet folding
Tertiary is 3-dimensional shape of polypeptide chain
Quaternary is relationship of multiple polypeptide chains
The four levels of protein
configuration
• Primary is unique
sequence of amino acids
• Secondary is alpha helix
or pleated sheet folding
• Tertiary is 3-dimensional
shape of polypeptide
chain
• Quaternary is
relationship of multiple
polypeptide chains
•
•
Protein Folding Tutorial:
Protein folding in Water
Bonds of protein Structure
• Hydrogen bond forms
the secondary structure
• Disulfide bonds stabilize
the tertiary structure of
protein molecules
• Disulfide bond between
2 polypeptide chains
create quaternary
structure
Protein Denaturation
• Function of a protein depends
on its ability to recognize and
bind to some other molecule
• Hostile environments such as
heat, acid or salts will change
a proteins 3-D shape and
destroy its ability to function
– raw egg white when cooked is
vastly different
Glycoprotein and Proteoglycan
• Proteins exist in combination with sugar.
• Glycoprotein: Protein + sugar chain. Found in cell
membrane. Serve as surface proteins.
• Proteoglycan: Protein + sugar chain. Also present in
cell membrane. Can have enzymatic activity.
Enzymes
• Enzymes are protein molecules that act as
catalysts by lowering Activation Energy
• Enzyme = apoenzyme + cofactor
– Apoenzymes are the protein portion
– Cofactors are nonprotein portion
• may be metal ion (iron, zinc, magnesium or calcium)
• may be organic molecule derived from a vitamin
• Enzymes usually end in suffix -ase and are named
for the types of chemical reactions they catalyze
• How Enzymes Work
• Enzyme Tutorial
• Enzyme Catalysis
Enzyme Functionality
• Highly specific
– acts on only one
substrate
• active site versus induced
fit
– speed up only one
reaction
• Very efficient
– speed up reaction up to
10 billion times faster
• Under nuclear control
• Co-factors first bind to
the enzyme = enzyme
activated
Enzyme Structure Interactions
Lock and Key: shape and active
site of enz is only compatible
w/
substrate,
forming
substrate enzyme complex
-enz reused but are eventually
decomposed=constant synthesis
-usually end in "ase" and take
name of substrate
Factors Affecting Enzyme Action
Temperature:
– 40oC, denaturation
Enzyme Saturation
Concentration of substrate
pH
– pepsin ( gastric protease) pH
2
– trypsin (pancreatic protease)
pH 8
Saturation
Cofactors
Cofactors can aid how enzyme
works. If they are organic, then
they are “coenzymes” these are
enzyme activators
Allosteric
&
Cofactors
inhibitors
activators
Competitive
Pharmacological Enzyme
Inhibitors
Allosteric Regulation
Biochemical Pathway
Competitive vs Noncompetitive
Inhibitors
• Competitive vs Noncompetitive Inhibitors
In this animation, the enzyme is olive, the substrate is green,
the competitive inhibitor is red and the products A & B are
yellow and blue. The enzyme has binding site into which either
the substrate or the competitive inhibitor may fit.
Which product, A or B, would most likely be a competitive
inhibitor?
• The enzyme has 2 binding sites, one for the
substrate (the active site) and the other for the
allosteric activator (the regulatory site). Allosteric
Activation
– Nerve gas permanently blocks pathways involved in nerve
message transmission, resulting in death.
– Penicillin, the first of the "wonder drug" antibiotics,
permanently blocks the pathways certain bacteria use to
assemble their cell wall components.
Examples of Enzyme function
• Ethylene levels cause changes in the production of different
enzymes, allowing fruits to ripen.
• In eukaryotic cells the mRNA transcript undergoes a series
of enzyme regulated modifications.
• The enzyme RNA-polymerase reads the DNA molecule in the
3' to 5' direction and synthesizes complementary mRNA
molecules that determine the order of amino acids in the
polypeptide.
• ATP Synthase
• DNA polymerase, ligase, RNA polymerase, helicase and
topoisomerase,
Positive Feedback
• Amplification occurs when the stimulus is further
activated, which in turn initiates an additional
response that produces system change
•
•
•
•
Lactation in mammals
Onset of labor in childbirth
Ripening of fruit
Blood clotting
• Estrogen & Progesterone in Female System
Negative Feedback/ Feedback
Inhibition
When the product is in abundance,
it binds competitively with its
enzyme's active site; as the
product is used up, inhibition is
reduced and more product can be
produced. In this way the
concentration of the product is
always controlled within a certain
range.
•Operons in gene regulation
•Temperature regulation in animals
•Plants response to water
limitations
1
A
2
B
3
C
4
D
1
A
2
B
3
C
4
D
5
E
6
F
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Resources
Animations:
Microbiology:
BioTopics Contents:
What is an Enzyme:
Lipid Behavior in Various Environments
Organic Molecules
Interactive Animations for Biochemical Processes
Biology Project Chemistry Tutorial
Chemistry Target Practice
Importance of Functional Groups
Functional groups Matching
Identify the Biomolecules Matching
"Hot Potatoes" Practice matching exercises
Factors that affect the rate of Chemical Reactions with Alka Seltzer
Properties of Water
Properties of Water & Transpiration
Enzyme Specificity Tutorial
Enzyme Kinetics Animation
Water Potential Quiz