Chapter 4
1. Describe or list the four stages thought necessary for the origin of life on Earth.
1. Production of nucleotides and amino acids
2. Polymerization of these monomers into polymers
3. Enclosing the polymers in membranes
4. Membrane-bound protocells acquire cellular properties
2. Explain for each of these stages, the evidences used to support the theory of
evolution, and the problems with accepting the theory.
Evidence for Biogenesis
1. Production of Monomers - In
1953 Stanley Miller produced an
enclosed system which circulated
reducing gases. A spark produced
an energy source and produced
simple organic molecules. Some
scientists have also suggested
that a meteorite impact could have
brought a sufficient amount of
organic molecules to earth.
Scientists have also theorized that
molecules can form at the edge of
deep sea vents where
superheated gases are vented.
Problems with this Theory
1. Production of Monomers - It is
likely that Miller experimented with
the wrong atmosphere. It is likely
that the early atmosphere was
composed mostly of Carbon
monoxide, carbon dioxide,
nitrogen, sulfur dioxide, and water,
which would have a much lower
yield of amino acids. Scientists
also have suggested that a
meteorite impact would destroy
most if not all of the organic
molecules it might introduce into
the atmosphere. The synthesis of
ribose would be impossible under
earthly conditions because there
would have needed to exist an
enzyme to specify the production
of the 5 '3 phosphodiester, when
the 5 ’2 phosphodiester is
preferred in most cases. RNA is
just too big and complex to have
formed in an early earth system. A
miracle would be required for the
formation of monomers and RNA
in an early earth system.
2. Production of polymers - There
is no known random process by
which non useful amino acids and
nucleotides are filtered out so that
the useful ones may be used to
form higher structures. It is unlikely
that polymerization would occur in
an aqueous environment, but on
solid surfaces due to hydrolysis
competing with condensation. The
random polymerization of
monomers into polymers can
create useful polymers, but the
odds of that happening are lower
than randomly selecting a specific
atom anywhere in the universe.
There are 180 different
arrangements for a nucleotide, but
the odds of linking 40 nucleotides
in arrangement in all DNA and
RNA is 10e-90. A miracle would
be required for the formation of
polymers in an early earth system.
3. Formation of Membranes -
Membranes require complex
structures to be formed, and must
come from preexisting
membranes. A miracle would be
required for the formation of
membranes in an early earth
system.
4. Production of Cells - the
probability of random developing
very specific amino acid
sequences is so small that it is
essentially impossible. Molecular
biology is too complex for the
production of even the simplest
cells to have occurred by chance.
Cells need a minimum of 493
genes. DNA replication in the
simplest prokaryotes requires 14
enzymes (25 polypeptides). DNA
cannot replicate with proteins,
which can’t be formed without
DNA and RNA. DNA, RNA, and
proteins are all required in the
process of cell production. In order
to form membrane bound
protocells, a miracle is required.
3. List the mixture of gasses used by Stanley Miller, and later but similar
experiments, and what organic molecules were produced, and which important
monomer has never been produced by these “spark-discharge” experiments.
Stanley Miller used H2O, H2, CH4, and NH3 and he produced amino acids. Similar
experiments produced amino acids, nucleotides, and sugars, but none of these
experiments have ever been able to produce Ribose.
4. Describe the advantages of proposing the first genes and enzymes were made of
RNA, and why so few genes and enzymes today are composed of RNA.
If the first genes and enzymes were made of RNA, the protocells would have been able
to produce like cells. Today, less genes and enzymes are composed of RNA because it
is much less stable than DNA.
1. List the three tenets of the cell theory.
1. The cell is the foundational unit of life.
2. All organisms are made of cells.
3. All cells come from preexisting cells.
5. Explain the benefits of having many small cells rather than fewer larger cells.
Many small cells would allow more oxygen and nutrients to diffuse into an organism due
to the large surface area as compared to an organism made up of one large cell.
6. List the three types of microscopes, and their resolutions, benefits and
downsides.
Light Microscope - uses light passing through sample to observe objects. Resolving
power = 200 nm
Transmission Electron Microscope - Uses an electron beam passing through
samples to view objects. Cells must be killed and stained with heavy metals in order to
block the electron beam. Resolution = 0.2 nm
Scanning Electron Microscope - Coats the surface of sample with heavy metal
stains and uses an electron beam to observe the surface of an object. View is more 3
dimensional
Resolution is about 10 nm
7. List the seven major prokaryotic cellular organelles, their basic structure, and
functions.
Organelle
Plasma Membrane
Nucleoid
Cytoplasm
Ribosomes
Cell wall
Capsule
Flagella
Structure
Single membrane
Aqueous
Aqueous
Solid (RNA and proteins)
Peptidoglycan membrane
Polysaccharides
Solid (proteins)
Function
Regulate Transport
Heredity
Biochemical reactions
Protein synthesis
Protection/support
Protection/hydration
Movement
8. For the following eukaryotic organelles, identify whether their structure is
aqueous, solid/made of proteins, or composed of membranes. If membranous, how
many membranes make up the organelle: Cytoplasm, Microtubules, Intermediate
Filaments, Microfilaments, Nucleus, Ribosomes, Rough Endoplasmic Reticulum,
Smooth Endoplasmic Reticulum, Golgi Apparatus, Lysosomes, Vacuoles, Peroxisomes,
Glyoxysomes, the Plasma Membrane, Mitochondria, Chloroplasts, Chromoplasts,
Leucoplasts, and the Cell Wall.
Organelle
Cytoplasm
Microtubules
Intermediate filaments
Microfilaments
Nucleus
Ribosomes
Rough ER
Smooth ER
Golgi Apparatus
Lysosomes
Vacuoles
Peroxisomes
Glyoxysomes
Plasma Membrane
Mitochondria
Chloroplasts
Chromoplasts
Leucoplasts
Structure
Aqueous
Solid
Solid
Solid
Membranous
Solid
Membranous
Membranous
Membranous
Solid
Membranous
Membranous
Membranous
Membranous
Membranous
Membranous
Membranous
Membranous
Number of Membranes
n/a
n/a
n/a
n/a
2 Membranes
n/a
1 Membrane
1 Membrane
1 Membrane
n/a
1 membrane
1 membrane
1 membrane
1 membrane
2 membranes
2 membranes
2 membranes
2 membranes
Cell Wall Solid n/a
9. For the same organelles, list the function(s) of that organelle.
Organelle
Cytoplasm
Microtubules
Intermediate filaments
Microfilaments
Nucleus
Ribosomes
Rough ER
Smooth ER
Golgi apparatus
Function
Made up of a wide variety of proteins,
many of which are important for the
formation of metabolic pathways like
glycolysis and fatty acid synthesis
Form cellular roads along which vesicles
and chromosomes move using molecular
motors (kinesin)
Maintain cellular shape and provide
mechanical strength to cells
1. Cellular movements (muscle
contraction, cytoplasmic streaming,
pseudopod formation.)
2. Cytoplasmic division (cytokinesis) to
divide a cell into two daughter cells during
mitosis and meiosis.
Stores DNA (hereditary information)
Protein synthesis
Synthesize glycoproteins, membrane-
bound proteins, and proteins destined for
various organelles
1. Detoxification of various poisons taken
into the body by modifying them to be
more polar and easy to excrete from the
cell.
2. Contains enzymes necessary for
glycogen and calcium metabolism
3. Synthesize phospholipids for
membranes and other lipids, including
steroid hormones
1. Add and/or modify carbohydrate portion
of glycoproteins
Lysosomes
Vacuoles
Peroxisomes
Glyoxysomes
Plasma membrane
Mitochondria
Chloroplasts
Chromoplasts
Leucoplasts
Cell Wall
2. Proteolysis - proteases cut proteins into
smaller, functional proteins
3. Concentrate, package, and sort
proteins before being transported to
cellular destinations
Digestion via hydrolytic reactions
1. Storage of food or waste material
2. Maintain turgor pressure
Contain catalase to degrade hydrogen
peroxide.
Contain enzymes for specific reactions
Turn lipids into carbohydrates for growth
1. Membrane transport - everything
leaving and entering the cell must pass
through the plasma membrane
2. Cell signaling - cells communicate with
each other and the external environment
3. Cell adhesion - multicellular organisms
need a way to hold cells together and
recognize each other.
Convert energy in organic molecules into
ATP (Aerobic respiration)
Photosynthesis
Produce and store various carotenoid
pigments producing red, yellow, and
orange colors in fruits and flowers
Store food (starch and fats)
Supports the cell
Limits the volume of the cell to help
maintain turgor pressure
Forms a barrier to prevent infection by
fungi and bacteria
10. List which organelles are included in the Cytoskeleton, and why they are
included together.
Microtubules - Microtubules are hollow tubes that contribute to the cytoskeleton,
serving as the road system used by vesicles and chromosomes
Intermediate filaments - More stable than other organelles in the cytoskeleton. They
are not constantly growing and shrinking.
Microfilaments - Support the plasma membrane and provide strength and shape to the
cell.
These are all fibrous organelles that provide structure to the cell as well as perform
some other functions. They work together to give the cell its strength and shape.
11. Explain why only nuclear proteins retain their transit sequence (Nuclear
Localization Signal).
They must return to the new location of the nucleus after it moves to a new location in
the cell following division.
12. Describe the function of the Nuclear Pores.
Nuclear pores act as channels that allow small molecules and ions to pass freely into
and out of the nucleus.
13. Explain why the Nucleus, Smooth ER, Rough ER, Golgi Apparatus, and
Lysosomes are all considered part of the Endomembrane System. What is the overall
function of the Endomembrane System?
They are all interrelated and their functions are in some way relative to the other
organelles in the endomembrane system. This system functions to transport and clean
up material from around the cell.
14. Explain why the Mitochondria and Chloroplast are considered “Semi
Autonomous”.
These two organelles can divide independently of the rest of the cell and even contain
their own DNA. These two organelles function with minimal reliance upon the other
organelles of the cell.
15. Explain the Endosymbiont Theory and what details of Mitochondrial and
Chloroplast structure it helps to explain.
There were large and small prokaryotic cells, some that could perform cellular
respiration and some that could perform photosynthesis. The larger of two cells would
engulf the smaller of the two without digesting it. Over time these organelles would
merge into a double membraned organelle that could either perform cellular respiration
(mitochondrion) or photosynthesis (chloroplast).
16. Describe the structure and function of the Extracellular Matrix.
The extracellular matrix is an interwoven mat of fibrous protein such as glycogen, a
matrix of glycoproteins (proteoglycans), proteins which link other proteins into a
continuous unit. The extracellular matrix helps connect adjacent cells together.
17. Explain the overall function of “Cotranslational Sorting”.
Many proteins take the first step in sorting them to organelles as they are translated.
18. Explain the steps in the process of Cotranslational Sorting.
Cotranslational Sorting
1. The first 12-20 Amino acids are non-polar and form an ER sorting signal.
2. A special protein, the signal recognition protein (SRP) finds and binds the signal
(hydrophobic amino acids)
3. SRP drags the ribosome to the ER and attaches to the SRP receptor
4. When SRP docks with the receptor, the protein chain is threaded through the channel
protein.
5. Protein is now threaded through the ER so it will end up in the lumen of the ER.
6. The signal recognition protein is now finished and leaves.
7. Protein synthesis now continues, the signal sequence is removed, and the protein will
end up in the lumen of the ER.
8. After the proteins are translated, possibly glycosylated and modified in other ways,
they are packaged into vesicles for transport to the destination organelle.
9. The vesicles destined for an organelle have specific proteins embedded in the
membrane to help concentrate the proteins being carried, and to help the vesicle fuse
with the proper target organelle.
19. Explain the process of Post-Translational Sorting and the role of Transit
Sequences
Proteins designed for the nucleus, microbodies, mitochondria, and chloroplast are
synthesized on ribosomes in the cytoplasm and sorted after they are made
Post-Translational Sorting
1. The first 12-20 amino acids on these proteins are special sequences which act
as sorting signals.
2. The transit sequence (Matrix-targeting sequence for mitochondria) is bound
and transported to a receptor membrane on the outer mitochondrial
membrane.
3. Chaperone proteins keep the protein in an unfolded condition so it can be
threaded through the channel protein more easily.
4. Once bound, the protein is threaded through a channel protein.
5. The protein is delivered to the matrix, its signal sequence removed, the
chaperone proteins detach, it assumes it’s active shape and it becomes active
in the duty of the mitochondria.
6. Other signal/transit sequences deliver proteins to the nucleus, chloroplast, and
microbodies.
7. Nuclear proteins are unique in that their signal/transit sequences are not
removed.
8. The position of the nucleus keeps changing with each cell division and nuclear
proteins must be gathered and redelivered to the new nucleus,
Chapter 5
1. Describe the current Fluid Mosaic structure of a typical biological membrane and
explain the arrangement of phospholipids and proteins in particular.
There are two layers of phospholipids (phospholipid bilayer) called leaflets (extracellular
and cytosolic). Phospholipids being amphipathic, the fatty acid tails are on the interior of
the bilayer while the polar heads border the surrounding organic material either inside or
outside the cell. Polar molecules cannot pass through the hydrophobic membrane center
(non-polar fatty acid tails) while non-polar molecules typically diffuse right through the
membrane. Proteins are embedded in the phospholipid bilayer. There can be anywhere
from 15 to 70 times more lipids than proteins in the membrane. Proteins usually
determine the exact function of the membrane as well as do the work of the membrane.
2. Describe the role that phospholipids, and proteins, play in the function of
membranes.
In a membrane, phospholipids have selective permeability, typically only allowing non-
polar molecules to diffuse to the other side of the membrane. Proteins do the work of the
membrane and determine the exact function of any given membrane.
3. Describe the main types of lipids found in membranes and the functions they
perform.
Up to 25% of an animal cell can be made of cholesterol and plant cells contain a lipid
with a similar structure called phytosterol.They both help to maintain the structure of the
membrane. Cholesterol affects the fluidity of the membrane at various temperatures.
4. Differentiate between peripheral and integral proteins, how are they defined?
Peripheral Proteins are loosely bound to the membrane. They are bound by hydrogen
or ionic bonds to transmembrane proteins or the heads of phospholipids. The exposed
portion of peripheral proteins are usually polar to allow for binding. Because they only
occur in one leaflet of the membrane, they cause membranes to be asymmetric with
differing functions.
Integral Proteins are more closely associated with the membrane. The exposed portion
of the integral proteins are usually nonpolar. There are two types of integral proteins.
Transmembrane proteins traverse the membrane with domains forming alpha helices.
They occur on both sides of the membrane and may be found on the cytoskeleton. Lipid
anchored proteins have a lipid covalently bound to the protein. The lipid is inserted into
the phospholipid bilayer, anchoring the protein.
5. Describe why biological membranes are described as fluid.
Phospholipids in the membrane are not covalently bonded and are free to move.
6. Describe why biological membranes are described as a mosaic.
The bilayer maintains its relative structure in that the phospholipids remain in their
respective leaflets. The bilayer is studded with proteins that make it “mosaic”
7. Explain what it means for a phospholipid to “flip-flop”.
It means that a phospholipid would swap from one leaflet of the membrane to the other
leaflet using a flippase.
8. Which of the three components of membranes can be asymmetric between the
two leaflets of the membrane?
The two leaflets can have different lipids due to the rarity in flip-flopping.
9. List the 3 factors which can influence membrane fluidity, and whether each would
increase or decrease fluidity.
1. Shorter hydrocarbon chains make the membrane more fluid
2. More unsaturated hydrocarbon chains make the membrane more fluid
3. More cholesterol makes the membrane more fluid at low temperatures and less
fluid at high temperatures
10. In what form are carbohydrates present in membranes? List the organelle and
leaflet in which they may be found.
Carbohydrates occur as glycolipids and glycoproteins. They can be found in the exterior
leaflet of the plasma membrane.
11. What function(s) do carbohydrates play in membranes?
Glycolipids and glycoproteins in the membrane function as antigens, identifying the cell
of an organism. They also label proteins with signals for cellular destinations. Some cells
also have a thick layer of carbohydrates outside the plasma membrane such as
glycocalyx, which shields the cell from the immune system of other cells.
12. In what organelle are Phospholipids synthesized, and how are they spread
throughout the cell to other organelles?
Phospholipids are synthesized in the smooth ER and spread throughout the cell by
insertion to the membrane followed by transfer from the cytosolic membrane to the
exterior membrane where they can then reach other organelles through transfer by
vesicles, lateral diffusion, and transport via lipid exchange proteins.
13. In what organelle are transmembrane proteins synthesized? How are they
inserted into the membrane when most proteins are large and polar and membranes are
so non-polar?
Transmembrane proteins are synthesized in the rough ER. Hydrophobic alpha helices
are left in the membrane, which form transmembrane proteins. Proteins are then moved
to other membranes by vesicles.
14. In what two organelles can glycoproteins be synthesized?
Glycoproteins are synthesized in the rough ER and the Golgi Apparatus.
15. Name the 3 major mechanisms that solutes can be transported through
membranes.
Passive diffusion, Facilitated diffusion, Primary active transport
16. Of these 3 major mechanisms, which use a protein transporter, which require the
expenditure of energy, and which can move the solute against the concentration
gradient?
Facilitated diffusion requires a protein transporter. Primary active transport expends
energy and can move solute against the concentration gradient.
17. Define the term Simple or Passive Diffusion.
Simple diffusion is the net movement of a solute from an area of high concentration to an
area of low concentration.
18. What is the energy source used to move solute by Simple Diffusion?
Kinetic energy moves solute in simple diffusion.
19. What are the 4 major solutes moved across membranes by Simple Diffusion?
CO2, N2, O2, Ethanol
20. What are the 4 major factors that determine the rate of Simple Diffusion, and do
they increase or decrease the rate?
Electrical charges decrease the rate of diffusion. High temperatures increase the rate of
diffusion, lower temperatures decrease, small molecules increase the rate, large
molecules decrease, From high concentration to low concentration increases the rate of
diffusion.
21. Define the term “Facilitated Diffusion”, paying particular attention to the factor
which facilitates the diffusion.
Facilitated diffusion is the diffusion of macromolecules and polar molecules through the
use of a protein.
22. Differentiate between channel proteins and carrier proteins in the mechanism of
transport.
Channel proteins act as a gate, allowing molecules to diffuse when they are opened.
Carrier proteins bind to the solute and carry it through the membrane.
23. Differentiate between ligand-gated and voltage-gated channels in the mechanism
which causes each to open.
Ligand-gated proteins open when a signal molecule (ligand) is bound. Voltage-gated
proteins open when a membrane is depolarized.
24. List the 3 types of protein transporters and indicate how many different solutes
are moved, and in what direction.
Uniports transfer one solute molecule in one direction. Symports transport two solute
molecules in the same direction. Antiports transfer two solute molecules in opposite
directions.
25. Define the term Primary Active Transport, indicating whether a protein
transporter is used, whether energy is expended, and whether it requires the
expenditure of energy.
Primary active transport is the transport of a substance against its concentration gradient
with the expenditure of energy. A transport protein is not required for primary active
transport.
26. Describe how Primary Active Transport is used to drive Secondary Active
Transport.
Primary Active Transport pumps an uneven amount of cations across the plasma
membrane
27. What type of protein transporter (see #24 above) is used for Secondary Active
Transport?
Secondary active transport uses an antiport.
28. Define the term Osmosis, and indicate which of the 3 major types of transport
(see #15 above) is used.
Osmosis is the diffusion of water through a semipermeable membrane. Osmosis is
passive transport.
29. List the 3 different types of solutions in which a cell can be placed, and which
way water would move through the membrane.
Isotonic solutions have the same concentration of water on both sides of the membrane
and water does not move between the two. A hypertonic solution has a higher
concentration of solute and lower concentration of water. A cell placed in a hypertonic
solution will lose volume. A hypotonic solution has a lower concentration of solute and a
higher concentration of water. A cell placed in a hypotonic solution will gain volume.
30. Define the terms Endocytosis and Exocytosis, explaining why they are
fundamentally different from the 3 mechanisms used to transport solute through a
membrane.
Endocytosis brings large size materials into the cell using vesicle formation. Exocytosis
discards materials from the cell using vesicles. These are inherently different from the
three mechanisms because they don’t require kinetic energy, proteins, or energy
expenditure, but vesicles.
31. How does receptor-mediated endocytosis differ from “regular” endocytosis? How
does the receptor aid the process?
Receptors concentrate materials before bringing them into the cell rather than just
bringing materials into the cell. Materials that are oddly or inconveniently shaped are
made more circular by the cell receptors so that they are easier to transport into the cell.
32. List the 3 major types of cell junctions and the function(s) of each.
Anchoring junctions are where integral proteins connect to the cytoskeletons of adjacent
cells.
Tight junctions limit movement of materials through intercellular spaces and limit the
movement of proteins within the membrane.
Gap junctions allow passage of ions and small molecules for communication between
cells.
33. Which of the 4 major classes of organic molecules compose the cell junctions?
Cell junctions are composed of proteins.
34. To what cellular organelle do the proteins of cell junctions connect, to enable
them to function?
Proteins connect to the cytoskeleton to enable the cell junctions to function.
Chapter 6
1. Be able to define Kinetic Energy, Potential Energy, Chemical Energy,
Metabolism, Enthalpy, Chemical Equilibrium, Biological Catalyst, Enzyme, Active Site,
Allosteric Protein.
Kinetic Energy - The energy possessed by all moving objects.
Potential Energy - Energy possessed due to location or arrangement.
Chemical Energy - Form of potential energy stored in molecules because of the
arrangement of atoms
Metabolism - The total chemical activity of a living organism.
Enthalpy - Total chemical energy of a molecule.
Chemical Equilibrium - Point in a reversible chemical reaction at which there is no
net change in the concentration of reactants and products.
Biological Catalyst - Substance that speeds up a chemical reaction between
biological molecules without being used up itself.
Enzyme - Protein catalysts, speeding up biochemical reactions.
Active Site - Site where substrate is bound and reaction is catalyzed.
Allosteric Protein - Protein with more than one shape depending upon whether or
not a ligand is bonded.
2. Differentiate between Anabolic and Catabolic Chemical Reactions and Pathways.
Catabolic Reactions occur when large molecules are broken down into smaller ones
with the release of potential chemical energy.
Anabolic Reactions occur when small molecules are built into larger ones with the input
of potential chemical energy.
Pathways are a series of chemical reactions.
3. Differentiate between Exergonic and Endergonic Reactions.
Exergonic Reactions release energy.
Endergonic Reactions require the input of energy.
4. If given the concentration of products and reactants at chemical equilibrium, be
able to calculate the Chemical Equilibrium Constant.
K = Products/Reactants
5. If given the Chemical Equilibrium Constant, and the concentration of either
products or reactants, be able to calculate the concentration of the other.
K = Products/Reactants
6. If given the Chemical Equilibrium Constant, and the initial concentration of
reactants for a reaction, be able to calculate the concentration of both products and
reactants at Chemical Equilibrium.
K = Products/Reactants
7. If given the Enthalpy of a chemical reaction’s products and
reactants, be able to calculate the change in Free Energy (∆G).
∆G (Enthalpy Products) - (Enthalpy Reactants)
8. If given ∆G and the enthalpy of either the products or reactants,
be able to calculate the enthalpy of the other.
∆G (Enthalpy Products) - (Enthalpy Reactants)
9. For an Exergonic or Endergonic Reaction, know whether a
positive or negative ∆G should be expected.
Exergonic - negative result
Endergonic - positive result
10. For an Exergonic or Endergonic Reaction, know whether the Chemical
Equilibrium should be greater or less than one.
Exergonic - Greater than one
Endergonic - Less than one
11. Explain why ATP is a high energy molecule.
Negative Phosphate groups repel one another.
12. Explain how Endergonic Reactions, which require the input of energy, are able to
occur. Where does the energy come from?
Endergonic reactions use the energy released in exergonic reactions.
13. Describe what Activation Energy is, and how Enzymes can reduce it.
Activation energy is the small amount of energy required in order for endergonic
reactions to take place. Enzymes bring reactants together, lowering the reaction energy
required for endergonic reactions to occur.
14. Differentiate between Competitive and Noncompetitive Inhibition.
Noncompetitive Inhibition Occurs when an inhibitor binds to a separate site, changing
the shape of an enzyme to an inactive conformation.
Competitive Inhibition Occurs when a molecule is shaped like the substrate and blocks
the active site of an enzyme.
15. Differentiate between Cofactors and Coenzymes.
Cofactors Are inorganic ions that bind to enzymes temporarily.
Coenzymes Are organic that bind to enzymes temporarily and participate in the
reaction.
16. What is a Rate-limiting Reaction in a Metabolic Pathway, and where in the
Pathway do they typically occur?
A rate limiting reaction is the slowest reaction in the metabolic pathway and limits the
overall rate of the metabolic pathway. It is normally at the front of the pathway.
17. Explain how Feedback Inhibition works to control a Metabolic Pathway so that
the product of the pathway is produced only when needed (in short supply).
Feedback Inhibition Occurs when a product from the end of a metabolic pathway acts
as a noncompetitive inhibitor, inactivating an enzyme early in the pathway.
18. What happens chemically when a protein is denatured? What type of chemical
bonds are broken?
Protein denaturation occurs when hydrogen bonds in the tertiary structure of the protein
are broken.
19. What are the most common denaturing agents?
Heat, strong acids, strong bases, highly charged ions
