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WorksheetsCell Bio - Exam 3
Total questions: 111
Worksheet time: 38mins
The fluid mosaic model describes...
A model of fluid dynamics
A theory about cell division
The structure of cell membranes
A type of fluid used in biology
Cell membranes are:
the outer layer of a cell that controls what enters and exits
the powerhouse of the cell
responsible for protein synthesis
the genetic material of the cell
The cell membrane is involved in:
protection and support
energy production
genetic information storage
photosynthesis
Receptors are:
proteins that bind to specific molecules and trigger a response in the cell
molecules that are always found on the surface of cells
enzymes that catalyze chemical reactions
lipids that store energy
What are membrane proteins?
Proteins that are part of or interact with cell membranes
Proteins that are found only in the nucleus
Proteins that are involved in DNA replication
Proteins that are responsible for muscle contraction
Transporter proteins are involved in which of the following functions?
Catalyzing chemical reactions
Transporting molecules across cell membranes
Providing structural support to cells
Storing genetic information
What is a lipid bilayer?
A single layer of lipids
A double layer of lipids
A triple layer of lipids
A quadruple layer of lipids
What is the most abundant type of membrane lipid?
Phospholipids
Cholesterol
Glycolipids
Sphingolipids
What does amphipathic mean in the context of membrane lipids?
Having both hydrophilic and hydrophobic parts
Being entirely hydrophilic
Being entirely hydrophobic
Being neither hydrophilic nor hydrophobic
What are hydrophilic molecules known as?
Hydrophilic molecules are known as polar molecules.
Hydrophilic molecules are known as non-polar molecules.
Hydrophilic molecules are known as hydrophobic molecules.
Hydrophilic molecules are known as amphipathic molecules.
Hydrophobic molecules are:
Polar/Charged
Non-polar/Uncharged
Inside the membrane, the tails are ________.
hydrophobic
hydrophilic
What is the most common type of phospholipid?
Phosphatidylcholine
Phosphatidylethanolamine
Phosphatidylserine
Phosphatidylinositol
A membrane is needed to separate the watery environment inside and outside the cell because:
it allows selective permeability, controlling what enters and exits the cell.
it provides structural support to the cell.
it helps in cell division.
it stores genetic information.
What happens to the lipid bilayer when exposed to water?
It dissolves completely
It forms a micelle
It forms a sphere
It remains unchanged
_______ make up 50% of a cell's mass (weight)
lipids
proteins
carbohydrates/sugars
water
What are the 4 types of membrane lipid movement?
Lateral diffusion, Flexion, Rotation, Flip-flop
Lateral diffusion, Flexion, Rotation, Translocation
Lateral diffusion, Flexion, Rotation, Transversion
Lateral diffusion, Flexion, Rotation, Transition
The most common type of membrane lipid movement is:
Lateral diffusion
Flip Flop
Rotation
Flexion
Flexion in membrane lipid movement involves kinking and un-kinking of what?
Hydrophobic tails
Hydrophobic heads
Hydrophilic tails
Hydrophilic heads
Flip flop in membrane lipid movement requires what?
no energy
specific pH
specific enzymes
electrochemical gradient
Lipid rafts are specialized domains in the cell membrane. What is their primary function?
Facilitate cell signaling
Transport oxygen
Store energy
Produce proteins
The properties of fatty-acid tails that affect membrane fluidity include:
Length of the fatty-acid tails and saturation
Presence of cholesterol and temperature
Type of proteins embedded in the membrane
Concentration of ions in the surrounding environment
How does tail length affect the tightness of packing in cell membranes?
Shorter tails increase fluidity
Longer tails increase fluidity
Shorter tails decrease fluidity
Longer tails decrease interactions
How do double bonds in tails affect the tightness of packing in cell membranes?
More double bonds increase fluidity
Less double bonds increase fluidity
More double bonds decrease fluidity
Less double bonds decrease fluidity
What is the difference between unsaturated and saturated fatty acid tails in terms of structure?
Unsaturated tails have no kinks
Saturated tails have kinks
Unsaturated tails are kinked
Saturated tails are kinked
Fill in the blank: Cholesterol stiffens the bilayer and makes it _______.
more rigid.
less rigid
more permeable.
less stable.
How does cholesterol respond to temperature? There are 2 correct answer choices here.
In cold conditions, it stiffens the bilayer and makes it more rigid.
In cold conditions, it loosens the bilayer and makes it more fluid.
In warm conditions, it stiffens the bilayer and makes it more rigid.
In warm conditions, it loosens the bilayer and makes it more fluid.
What is an asymmetrical bilayer?
The 2 layers look the same
The 2 layers looks different
Flippase is an enzyme that catalyzes the transfer of _______ from one layer to the other.
phospholipids
transmembrane proteins
hydrophobic molecules
"cargo"
Transmembrane proteins are characterized by their ability to:
Span across the cell membrane
Bind to DNA
Catalyze chemical reactions
Transport oxygen in blood
Monolayer associated proteins are characterized by their ability to:
Bind to the lipid bilayer without spanning it
Span the entire lipid bilayer
Exist only in the cytoplasm
Form covalent bonds with lipids
______ membrane proteins are covalently attached to lipid molecules.
Bilayer
Lipid-linked
Glycolipid
Phosopholipid
Membrane proteins are involved in which of the following functions?
Signaling
DNA replication
Photosynthesis
Glycolysis
In what form do polypeptide (PP) chains cross the bilayer? 2 right answers here.
As alpha-helices
As beta-sheets
As random coils
As globular proteins
What part of an alpha helix is hydrophilic?
The back
The backbone
The R-groups
The front
What are peptide bonds and what is their significance?
Peptide bonds are covalent chemical bonds formed between two amino acid molecules.
Peptide bonds are ionic bonds formed between two nucleotides.
Peptide bonds are hydrogen bonds formed between two water molecules.
Peptide bonds are metallic bonds formed between two metal atoms.
Polypeptide (PP) chains cross the bilayer by:
diffusion through the lipid bilayer
transport through protein channels
endocytosis
active transport
What are the characteristics and functions of detergents in disrupting hydrophobic associations?
Detergents have hydrophilic and hydrophobic parts that allow them to interact with and disrupt hydrophobic associations.
Detergents are purely hydrophilic and do not interact with hydrophobic associations.
Detergents are purely hydrophobic and enhance hydrophobic associations.
Detergents do not affect hydrophobic associations at all.
The cell cortex is a specialized layer of cytoplasm on the inner face of the plasma membrane. What is its primary role?
To provide structural support to the cell
To facilitate cell division
To store genetic information
To transport nutrients across the membrane
The main component of the cell cortex of red blood cells (RBCs) is
Spectrin
Actin
Myosin
Tubulin
Integrins (intracellular-attachment proteins) overall MAIN function:
binding to the extracellular matrix
facilitating cell-cell adhesion
transporting ions across the membrane
acting as enzymes in metabolic pathways
Proteins can move freely within bilayers.
True
False
Membrane domains are specialized regions within a cell membrane that serve specific functions. Which of the following best describes membrane domains?
Regions within a cell membrane that are identical in composition and function.
Specialized regions within a cell membrane that serve specific functions.
Areas of the cell membrane that are devoid of proteins and lipids.
Sections of the cell membrane that are impermeable to all substances.
List the ways to restrict protein movement in the membrane.
By anchoring proteins to the cytoskeleton
By forming tight junctions
By using lipid rafts
All of the above
What are tight junctions?
A type of cell junction that prevents the passage of molecules and ions through the space between cells.
A type of cell junction that allows the passage of molecules and ions between cells.
A type of cell junction that connects the cytoplasm of two cells.
A type of cell junction that anchors cells to the extracellular matrix.
What is the carbohydrate layer?
A protective layer of polysaccharides on the surface of cells
A type of protein found in the cell membrane
A lipid layer that surrounds the nucleus
A type of nucleic acid involved in energy transfer
What are the functions of the carbohydrate layer?
Protection and support
Energy storage
Signal transduction
All of the above
Feasibility of diffusion through the membrane/lipid bi-layer depends on _______.
the properties of the molecules, such as size, polarity, and charge.
the temperature of the environment only.
the color of the molecules.
the age of the cell.
What is the main function of carrier (accessory) proteins in relation to the plasma membrane?
Translation
Transporting
Signaling
Polymerizing
Passive transport involves movement across the membrane from ______ to ______ concentrations.
high to low
low to high
The difference between passive and active transport is:
Passive transport requires energy, while active transport does not.
Active transport requires energy, while passive transport does not.
Both require energy.
Neither require energy.
What is facilitated diffusion?
A process of passive transport of molecules across a membrane via specific transmembrane proteins
A type of active transport requiring energy to move molecules against a concentration gradient
The movement of water molecules through a selectively permeable membrane
The process of engulfing particles by the cell membrane to form a vacuole
Which of the following is true regarding coupled reactions?
Coupled reactions use the energy from one reaction to drive another.
Coupled reactions occur simultaneously.
Coupled reactions are energetically unfavorable
Coupled reactions do not involve energy transfer.
List the main types of active transport.
Endocytosis, exocytosis, and pinocytosis
Light-driven, ATP-driven, Coupled
Consitutive, Secretive
Simple diffusion, facilitated diffusion, and osmosis
The function of an ATP driven pump is to:
transport molecules across cell membranes
synthesize proteins
replicate DNA
produce energy in the form of ATP
Light driven transporters couple uphill transport with the input of energy from what source?
light energy
chemical energy
thermal energy
mechanical energy
What is the driving force that moves ions across the membrane called?
Electrochemical gradient
Osmotic pressure
Hydrostatic pressure
Concentration gradient
Chemically, solutes want to move from where there's a lot of them (high concentration) to where there's less of them (low concentration).
True
False
If electrical and chemical aspects want the same thing, what type of driving force is it?
Electrochemical
Mechanical
Thermal
Gravitational
The difference in voltage between each side of the membrane is called:
Membrane potential
Action potential
Resting potential
Threshold potential
Which ion has a much higher concentration outside the cell than inside?
Ca2+
Na+
K+
What is the chemical symbol for Calcium?
Ca
C
Cl
K
Which ion is the most tightly regulated?
Which type of transport involves molecules moving opposite directions?
Inport
Symport
Antiport
Transport
Which type of transport involves molecules moving in the same direction?
Symport
Antiport
Diffusion
Osmosis
What happens to Na+ in the Glucose/Na+ symporter?
Na+ "hitches a ride" with glucose
Na+ "blocks" the glucose transport
Na+ "competes" with glucose for transport
Na+ "inhibits" the process
How is glucose passively released?
From intestinal epithelia cells for other tissues to use
Through active transport mechanisms
Via facilitated diffusion involving ATP
By osmosis across cell membranes
What happens to Ca2+ after muscle contraction?
Ca2+ pump returns Ca2+ to the sarcoplasmic reticulum
Ca2+ is converted into another element
Ca2+ is permanently removed from the cell
Ca2+ binds permanently to troponin
What are the 2 main types of Membrane Transport proteins?
Channel, Receptor
Channel, Transporter
Transporter, Anchor
Anchor, Receptor
Gated ion channels are not continuously open.
True
False
What are the different types of gated ion channels?
Ligand, Chemical, Voltage
Chemical, Mechanical, Voltage
Ligand, Mechanical, Voltage
Ligand, Mechanical, Chemical
Nicotinic Acetylcholine Receptor is a type of ______-gated ion channel.
mechanical
voltage
Voltage gated ion channels respond to changes in ______ potential.
membrane
action
The Resting Membrane Potential (RMP) is:
the electrical potential difference across the cell membrane when the cell is at rest
the electrical potential difference across the cell membrane during an action potential
the electrical potential difference across the cell membrane when the cell is depolarized
the electrical potential difference across the cell membrane when the cell is hyperpolarized
Leaky K+ channels are:
channels that allow potassium ions to leak out of the cell, maintaining the resting membrane potential
channels that allow sodium ions to enter the cell, causing depolarization
channels that transport calcium ions across the cell membrane
channels that are impermeable to all ions
The giant squid is significant in neuron studies because of its:
large axon size, which allows for easier study of nerve impulses
ability to regenerate neurons quickly
unique neurotransmitter production
role in marine ecosystems
An action potential is:
a sudden increase in voltage across a cell's membrane
a gradual decrease in voltage across a cell's membrane
a constant voltage across a cell's membrane
no change in voltage across a cell's membrane
A stimulus depolarizes the membrane to trigger an action potential by:
opening sodium channels, allowing Na+ ions to enter the cell
closing potassium channels, preventing K+ ions from leaving the cell
increasing the permeability of the membrane to chloride ions
decreasing the permeability of the membrane to calcium ions
The direction of action potentials is:
Bidirectional
Unidirectional
Multidirectional
Non-directional
The 3 conformations of voltage-gated Na+ channels are:
open, closed, and inactive
active, passive, and neutral
conductive, non-conductive, and semi-conductive
polarized, depolarized, and repolarized
A propagating action potential (signal) is prevented from going backwards by:
the refractory period (inactivation of Na+ channels)
the myelin sheath.
the synaptic cleft.
the activation of Na+ channels
A synapse is a:
junction between two neurons
type of neurotransmitter
part of the neuron cell body
type of brain cell
How does an action potential/signal switch from electrical to chemical?
Through the release of neurotransmitters at the synapse
By changing the ion concentration inside the neuron
Through the movement of electrical impulses along the axon
By altering the membrane potential of the neuron
The difference between excitatory and inhibitory synapses is:
Excitatory synapses increase the likelihood of the firing action potential of a cell, while inhibitory synapses decrease it.
Excitatory synapses decrease the likelihood of the firing action potential of a cell, while inhibitory synapses increase it.
Both excitatory and inhibitory synapses increase the likelihood of the firing action potential of a cell.
Both excitatory and inhibitory synapses decrease the likelihood of the firing action potential of a cell.
The synaptic cleft is:
a gap between neurons where neurotransmitters are released
a part of the neuron that receives signals
a type of neurotransmitter
a protective layer around the neuron
A signal is relayed between neurons without physically touching by:
direct electrical connection
chemical synapses
magnetic fields
mechanical vibrations
The components of neuron structure are:
Dendrites, Axon, Cell body
Nucleus, Mitochondria, Ribosome
Cell wall, Chloroplast, Vacuole
Cytoplasm, Endoplasmic reticulum, Golgi apparatus
Where does the post-synaptic acetylcholine receptor bind?
On the pre-synaptic neuron
On the post-synaptic neuron
In the synaptic cleft
On the axon terminal
Electrophysiology is the study of?
Electrical properties of biological cells and tissues
Chemical reactions in the body
Genetic information processing
Mechanical movements in organisms
Neurogenesis is the process of:
cell death in the brain
formation of new neurons
synaptic pruning
neurotransmitter release
When is our brain in top shape?
In your late 50's - early 60's
In your late 30's - early 40's
In your late 20's - early 30's
In your late 70's - early 80's
The function of membrane enclosed organelles is to:
store genetic information
synthesize proteins
compartmentalize cellular processes
provide structural support
The endomembrane system is a group of membranes and organelles in eukaryotic cells that works together to modify, package, and transport lipids and proteins. How was it formed?
Through the invagination of the plasma membrane
By the fusion of vesicles
From the endosymbiotic theory
By the division of pre-existing organelles
Proteins get from the cytosol into the nucleus by:
diffusion through the nuclear membrane
active transport through nuclear pores
being packaged into vesicles
osmosis
Proteins get from the cytosol into the ER/mitochondria/chloroplast through:
vesicular transport
protein translocators
diffusion
osmosis
Proteins get from the ER onward and from one organelle to another by:
diffusion through membranes
vesicular transport
active transport using ATP
osmosis
Signal sequences are ________
hydrophobic
hydrophilic
amphipathic
What is the nuclear envelope continuous with?
The DNA
The Golgi
The ER Lumen
The plasma membrane
which type of filaments can change length?
intermediate
microtubule
micro
what is the name of the quaternary protein structure intermediate filaments form into?
twisted-twisted
di-helices
coiled-coiled
alpha-dispiro
More intermediate filaments make the structures
stronger
weaker
Which is correct
Nuclear Lamins make Nuclear Lamina
Nuclear Lamina make Nuclear Lamins
The Positive end of a microtubule
grows (polymerizes)
shrinks (depolymerizes)
stays stagnant
Changes Length (both)
Microtubules function is dictated by
organizing centers
if it's a plus/minus type
Environment
Basal Body is for _____
Centrosome + Centrioles are for _____
Cilia
Mitotic Spindle
Mitotic Spindle
Cilia
Capping Proteins will make the cell...
non-polar (same shape)
polar (shape change)
Kinesins move to the ____ end
Dynein's move to the ____ end
+
-
-
+
haha, that's a trick question! it depends
Cilia and Flagellum primarily move
themselves
fluid around them
Which is used in the power stroke
kinesin
dynein
Myosin is actins
motor protein
actin binding protein
carrier protein
after the lamellipodium attaches to the integrin, what does myosin do?
contract
release
