biology 102 module1 exam ( 4 versions) question with detailed answers
Vmax - ANSWERS-Vmax represents the maximum rate at which an enzyme can
catalyze a reaction. A significantly higher Vmax in the control indicates that the normal
OAT enzyme operates much more efficiently than the mutant version.
KM - ANSWERS-KM reflects the substrate concentration needed to reach half of Vmax,
essentially indicating enzyme-substrate binding affinity. A 50-fold increase in KM means
that the mutant OAT requires much more substrate (ornithine) to function effectively.
Dominant-Negative Effect - ANSWERS-The dominant-negative effect refers to a
situation where a mutant protein interferes with the function of a normal protein. In this
context, the authors tested whether the mutant OAT could inhibit the activity of the
normal enzyme.
Effect of Arginine Injection - ANSWERS-In individuals with normal OAT, arginine
injections lead to a temporary increase in plasma ornithine, which is efficiently
processed. However, in individuals with mutated OAT, this results in an accumulation of
ornithine due to impaired conversion to P5C and proline.
Dietary Recommendations for Gyrate Atrophy - ANSWERS-A low-protein, low-ornithine,
and low-arginine diet helps reduce the substrate load on the defective pathway,
minimizing ornithine buildup and slowing GA progression.
Significance of Higher Vmax in Control - ANSWERS-A significantly higher Vmax in the
control indicates that the normal OAT enzyme operates much more efficiently than the
mutant version, suggesting that the mutation reduces the enzyme's catalytic capability.
50-Fold Increase in KM - ANSWERS-Yes, the increase in KM supports the conclusion.
A 50-fold increase in KM means that the mutant OAT requires much more substrate
(ornithine) to function effectively, signifying a reduced binding affinity due to the
mutation.
Testing Mutant OAT Effect - ANSWERS-The authors performed this experiment to
determine if the mutant OAT had a dominant-negative effect. They found that adding
mutant OAT did not inhibit the activity of the normal enzyme, suggesting the mutation's
impact is specific to the mutant enzyme itself.
Micrometer - ANSWERS-A unit of length equal to one millionth (10⁻⁶) of a meter or 10⁻⁴
centimeters.
Light Microscope - ANSWERS-Uses visible light and glass lenses to magnify cells up to
1000 times and resolve details as small as 0.2 µm. Requires careful sample preparation
.
,Fluorescence Microscope - ANSWERS-A specialized type of light microscope that uses
fluorescent dyes to label specific cell components. These dyes absorb light at one
wavelength and emit it at another, enabling visualization of structures smaller than 0.2
µm.
Electron Microscope - ANSWERS-Uses a beam of electrons instead of light to achieve
much higher resolution, revealing details as small as 1 nm.
Transmission Electron Microscope (TEM) - ANSWERS-Used for thin-section imaging of
internal structures.
Scanning Electron Microscope (SEM) - ANSWERS-Used to study surface details.
Prokaryote - ANSWERS-Single-celled organisms lacking a nucleus. They include two
domains: Bacteria and Archaea.
Bacteria - ANSWERS-The most diverse and abundant domain of prokaryotic life, found
in various shapes (spherical, rod-shaped, spiral). They inhabit environments ranging
from soil to human bodies.
Archaea - ANSWERS-A domain of prokaryotic organisms distinct from bacteria, often
inhabiting extreme environments. They are structurally similar to bacteria but
biochemically and genetically distinct.
Eukaryote - ANSWERS-Organisms whose cells contain a nucleus and organelles,
including plants, animals, fungi, and protists. They are typically larger and more
complex than prokaryotes.
Nerve Cell (Neuron) - ANSWERS-Neurons have long extensions called axons and
dendrites, which are essential for transmitting electrical signals over long distances and
receiving signals from other neurons.
Red Blood Cell (Erythrocyte) - ANSWERS-Red blood cells are biconcave in shape,
increasing their surface area for efficient gas exchange. They lack a nucleus,
maximizing space for hemoglobin to carry oxygen.
Central Dogma - ANSWERS-The framework for understanding the transfer of sequence
information between information-carrying biopolymers in living organisms.
Light Microscopy vs. Electron Microscopy - ANSWERS-Light microscopy uses visible
light while electron microscopy uses a beam of electrons.
Fluorescence Microscopy vs. Regular Light Microscopy - ANSWERS-Fluorescence
microscopy uses fluorescent dyes to visualize specific structures, while regular light
microscopy does not.
,Living Cells Visualization - ANSWERS-Electron microscopy does NOT allow you to
visualize living cells.
Eukaryotes vs. Prokaryotes - ANSWERS-Eukaryotes have a nucleus and organelles,
while prokaryotes lack a nucleus.
Central Dogma - ANSWERS-Describes the flow of genetic information within a cell:
DNA is transcribed into RNA, and RNA is translated into protein.
Light Microscopy - ANSWERS-Uses visible light to illuminate specimens with a
maximum resolution of ~200 nm and allows observation of living cells.
Electron Microscopy - ANSWERS-Uses a beam of electrons with much shorter
wavelengths than light, achieving resolution up to ~1 nm for biological specimens, but
does not allow observation of living cells.
Fluorescence Microscopy - ANSWERS-Uses fluorescent dyes or proteins to label
specific cell components and employs specialized filters to detect emitted fluorescence.
Regular Light Microscopy - ANSWERS-Relies on natural light and staining techniques
without fluorescence, limited in distinguishing specific molecular features.
Eukaryotes - ANSWERS-Organisms that contain a nucleus to house DNA, possess
membrane-bound organelles, and are typically larger and more complex.
Prokaryotes - ANSWERS-Organisms that lack a nucleus, have DNA found in the
cytoplasm, and do not possess membrane-bound organelles.
Actin Filaments - ANSWERS-Thin, flexible protein threads made of actin that support
cell shape, enable cell crawling, and are essential for muscle contraction and cell
division.
Cell Wall - ANSWERS-A rigid layer surrounding plant, fungal, and some prokaryotic
cells, composed of cellulose in plants, providing mechanical strength and protection.
Chromosome - ANSWERS-A thread-like structure made of DNA and proteins that
carries genetic information and ensures accurate segregation during cell division.
Cytoplasm - ANSWERS-The entire contents within a cell's plasma membrane,
excluding the nucleus, including the cytosol and all organelles.
Cytoskeleton - ANSWERS-A network of protein filaments (actin filaments, intermediate
filaments, microtubules) that provides mechanical support and facilitates movement.
, Cytosol - ANSWERS-The fluid part of the cytoplasm where many metabolic reactions
occur, excluding organelles and large molecular structures.
Endocytosis - ANSWERS-The process by which cells internalize extracellular
substances through vesicle formation.
Exocytosis - ANSWERS-The process by which cells expel substances, like proteins or
waste, by vesicles fusing with the plasma membrane.
Extracellular Matrix - ANSWERS-A complex network of proteins and polysaccharides
secreted by cells that provides structural support and facilitates communication between
cells.
Protozoans - ANSWERS-Single-celled eukaryotic organisms, often motile, that can be
free-living or parasitic, such as Amoeba and Paramecium.
Intermediate Filaments - ANSWERS-Rope-like fibers providing tensile strength and
mechanical support, particularly in animal cells.
Microtubules - ANSWERS-Hollow cylinders made of tubulin that are part of the
cytoskeleton.
Cytoskeleton - ANSWERS-Provides structural support to maintain cell shape, facilitates
intracellular transport of organelles and vesicles, drives cell motility via extensions like
lamellipodia and filopodia, segregates chromosomes during cell division, and organizes
the intracellular environment.
Model Organism - ANSWERS-Species extensively studied to understand biological
processes, e.g., E. coli, yeast, C. elegans, Drosophila, and mice. These organisms are
essential for research due to their genetic simplicity and similarity to humans in key
processes.
Nuclear Envelope - ANSWERS-A double membrane surrounding the nucleus,
containing pores that regulate transport between the nucleus and cytoplasm.
Organelle - ANSWERS-Specialized subunits within cells, such as mitochondria,
chloroplasts, and the Golgi apparatus, performing specific functions.
Photosynthesis - ANSWERS-The process in which plants, algae, and some bacteria
convert light energy into chemical energy stored in glucose, using chloroplasts.
Plasma Membrane - ANSWERS-A lipid bilayer that encloses the cell, controlling the
movement of substances in and out while providing a platform for cell signaling and
interaction.
Vmax - ANSWERS-Vmax represents the maximum rate at which an enzyme can
catalyze a reaction. A significantly higher Vmax in the control indicates that the normal
OAT enzyme operates much more efficiently than the mutant version.
KM - ANSWERS-KM reflects the substrate concentration needed to reach half of Vmax,
essentially indicating enzyme-substrate binding affinity. A 50-fold increase in KM means
that the mutant OAT requires much more substrate (ornithine) to function effectively.
Dominant-Negative Effect - ANSWERS-The dominant-negative effect refers to a
situation where a mutant protein interferes with the function of a normal protein. In this
context, the authors tested whether the mutant OAT could inhibit the activity of the
normal enzyme.
Effect of Arginine Injection - ANSWERS-In individuals with normal OAT, arginine
injections lead to a temporary increase in plasma ornithine, which is efficiently
processed. However, in individuals with mutated OAT, this results in an accumulation of
ornithine due to impaired conversion to P5C and proline.
Dietary Recommendations for Gyrate Atrophy - ANSWERS-A low-protein, low-ornithine,
and low-arginine diet helps reduce the substrate load on the defective pathway,
minimizing ornithine buildup and slowing GA progression.
Significance of Higher Vmax in Control - ANSWERS-A significantly higher Vmax in the
control indicates that the normal OAT enzyme operates much more efficiently than the
mutant version, suggesting that the mutation reduces the enzyme's catalytic capability.
50-Fold Increase in KM - ANSWERS-Yes, the increase in KM supports the conclusion.
A 50-fold increase in KM means that the mutant OAT requires much more substrate
(ornithine) to function effectively, signifying a reduced binding affinity due to the
mutation.
Testing Mutant OAT Effect - ANSWERS-The authors performed this experiment to
determine if the mutant OAT had a dominant-negative effect. They found that adding
mutant OAT did not inhibit the activity of the normal enzyme, suggesting the mutation's
impact is specific to the mutant enzyme itself.
Micrometer - ANSWERS-A unit of length equal to one millionth (10⁻⁶) of a meter or 10⁻⁴
centimeters.
Light Microscope - ANSWERS-Uses visible light and glass lenses to magnify cells up to
1000 times and resolve details as small as 0.2 µm. Requires careful sample preparation
.
,Fluorescence Microscope - ANSWERS-A specialized type of light microscope that uses
fluorescent dyes to label specific cell components. These dyes absorb light at one
wavelength and emit it at another, enabling visualization of structures smaller than 0.2
µm.
Electron Microscope - ANSWERS-Uses a beam of electrons instead of light to achieve
much higher resolution, revealing details as small as 1 nm.
Transmission Electron Microscope (TEM) - ANSWERS-Used for thin-section imaging of
internal structures.
Scanning Electron Microscope (SEM) - ANSWERS-Used to study surface details.
Prokaryote - ANSWERS-Single-celled organisms lacking a nucleus. They include two
domains: Bacteria and Archaea.
Bacteria - ANSWERS-The most diverse and abundant domain of prokaryotic life, found
in various shapes (spherical, rod-shaped, spiral). They inhabit environments ranging
from soil to human bodies.
Archaea - ANSWERS-A domain of prokaryotic organisms distinct from bacteria, often
inhabiting extreme environments. They are structurally similar to bacteria but
biochemically and genetically distinct.
Eukaryote - ANSWERS-Organisms whose cells contain a nucleus and organelles,
including plants, animals, fungi, and protists. They are typically larger and more
complex than prokaryotes.
Nerve Cell (Neuron) - ANSWERS-Neurons have long extensions called axons and
dendrites, which are essential for transmitting electrical signals over long distances and
receiving signals from other neurons.
Red Blood Cell (Erythrocyte) - ANSWERS-Red blood cells are biconcave in shape,
increasing their surface area for efficient gas exchange. They lack a nucleus,
maximizing space for hemoglobin to carry oxygen.
Central Dogma - ANSWERS-The framework for understanding the transfer of sequence
information between information-carrying biopolymers in living organisms.
Light Microscopy vs. Electron Microscopy - ANSWERS-Light microscopy uses visible
light while electron microscopy uses a beam of electrons.
Fluorescence Microscopy vs. Regular Light Microscopy - ANSWERS-Fluorescence
microscopy uses fluorescent dyes to visualize specific structures, while regular light
microscopy does not.
,Living Cells Visualization - ANSWERS-Electron microscopy does NOT allow you to
visualize living cells.
Eukaryotes vs. Prokaryotes - ANSWERS-Eukaryotes have a nucleus and organelles,
while prokaryotes lack a nucleus.
Central Dogma - ANSWERS-Describes the flow of genetic information within a cell:
DNA is transcribed into RNA, and RNA is translated into protein.
Light Microscopy - ANSWERS-Uses visible light to illuminate specimens with a
maximum resolution of ~200 nm and allows observation of living cells.
Electron Microscopy - ANSWERS-Uses a beam of electrons with much shorter
wavelengths than light, achieving resolution up to ~1 nm for biological specimens, but
does not allow observation of living cells.
Fluorescence Microscopy - ANSWERS-Uses fluorescent dyes or proteins to label
specific cell components and employs specialized filters to detect emitted fluorescence.
Regular Light Microscopy - ANSWERS-Relies on natural light and staining techniques
without fluorescence, limited in distinguishing specific molecular features.
Eukaryotes - ANSWERS-Organisms that contain a nucleus to house DNA, possess
membrane-bound organelles, and are typically larger and more complex.
Prokaryotes - ANSWERS-Organisms that lack a nucleus, have DNA found in the
cytoplasm, and do not possess membrane-bound organelles.
Actin Filaments - ANSWERS-Thin, flexible protein threads made of actin that support
cell shape, enable cell crawling, and are essential for muscle contraction and cell
division.
Cell Wall - ANSWERS-A rigid layer surrounding plant, fungal, and some prokaryotic
cells, composed of cellulose in plants, providing mechanical strength and protection.
Chromosome - ANSWERS-A thread-like structure made of DNA and proteins that
carries genetic information and ensures accurate segregation during cell division.
Cytoplasm - ANSWERS-The entire contents within a cell's plasma membrane,
excluding the nucleus, including the cytosol and all organelles.
Cytoskeleton - ANSWERS-A network of protein filaments (actin filaments, intermediate
filaments, microtubules) that provides mechanical support and facilitates movement.
, Cytosol - ANSWERS-The fluid part of the cytoplasm where many metabolic reactions
occur, excluding organelles and large molecular structures.
Endocytosis - ANSWERS-The process by which cells internalize extracellular
substances through vesicle formation.
Exocytosis - ANSWERS-The process by which cells expel substances, like proteins or
waste, by vesicles fusing with the plasma membrane.
Extracellular Matrix - ANSWERS-A complex network of proteins and polysaccharides
secreted by cells that provides structural support and facilitates communication between
cells.
Protozoans - ANSWERS-Single-celled eukaryotic organisms, often motile, that can be
free-living or parasitic, such as Amoeba and Paramecium.
Intermediate Filaments - ANSWERS-Rope-like fibers providing tensile strength and
mechanical support, particularly in animal cells.
Microtubules - ANSWERS-Hollow cylinders made of tubulin that are part of the
cytoskeleton.
Cytoskeleton - ANSWERS-Provides structural support to maintain cell shape, facilitates
intracellular transport of organelles and vesicles, drives cell motility via extensions like
lamellipodia and filopodia, segregates chromosomes during cell division, and organizes
the intracellular environment.
Model Organism - ANSWERS-Species extensively studied to understand biological
processes, e.g., E. coli, yeast, C. elegans, Drosophila, and mice. These organisms are
essential for research due to their genetic simplicity and similarity to humans in key
processes.
Nuclear Envelope - ANSWERS-A double membrane surrounding the nucleus,
containing pores that regulate transport between the nucleus and cytoplasm.
Organelle - ANSWERS-Specialized subunits within cells, such as mitochondria,
chloroplasts, and the Golgi apparatus, performing specific functions.
Photosynthesis - ANSWERS-The process in which plants, algae, and some bacteria
convert light energy into chemical energy stored in glucose, using chloroplasts.
Plasma Membrane - ANSWERS-A lipid bilayer that encloses the cell, controlling the
movement of substances in and out while providing a platform for cell signaling and
interaction.
