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WorksheetsCell Bio 1
Total questions: 98
Worksheet time: 49mins
Which of the following is NOT a major type of phospholipid found in cells?
Phosphatidylserine
Phosphatidylcholine
Phosphatidylethanolamine
Triglyceride
What effect do cis double bonds in fatty acids have on membrane fluidity?
Increase membrane fluidity
Decrease membrane fluidity
Have no effect on membrane fluidity
Make the membrane rigid
Which type of fatty acid has straight chains that stack neatly and result in low membrane fluidity?
Saturated fats
Unsaturated fats
Trans fats
Essential fats
What is the function of cholesterol at low temperatures in the membrane?
Increases fluidity
Decreases fluidity
Acts as a receptor
Creates kinks in fatty acids
Which factor increases membrane fluidity?
High temperature
Low temperature
Saturated fatty acids
High cholesterol at high temperature
What is the main function of receptor proteins in the cell membrane?
Communication and detection of external signals
Transport of molecules across the membrane
Providing structural support
Increasing membrane fluidity
Which type of protein spans the entire membrane and is embedded within the bilayer?
Integral (Transmembrane) proteins
Peripheral proteins
Lipid-bound proteins
Glycoproteins
What is the main function of channel proteins?
Passive transport of molecules
Active transport of ions
Cell recognition
Anchoring the cell
Which type of protein is loosely attached to the membrane surface and is easily detached?
Peripheral proteins
Integral proteins
Carrier proteins
Lipid-bound proteins
What is required for carrier proteins to move substances against the concentration gradient?
ATP/energy
Water
Oxygen
Glucose
Where are lipid-bound proteins located?
Inside the lipid bilayer
On the outer surface of the membrane
Spanning the membrane
Attached to glycoproteins
What do carbohydrates attach to in the membrane?
Lipids or proteins
Water molecules
DNA
Cholesterol
What is the function of carbohydrates on the outer surface of the membrane?
Cell recognition and communication
Active transport
Anchoring the cell
Passive transport
Which protein type is involved in passive ion/molecule transport and does not require energy?
Channel (integral)
Carrier (integral)
Peripheral
Lipid-bound
Which protein type is rare and has limited function?
Lipid-bound
Integral
Peripheral
Carrier
What is the direction of transport for channel (integral) proteins?
High to low concentration
Low to high concentration
Either direction
No direction
What does the term "extracellular" refer to?
Inside the cell
Outside the cell
Between cells
Facing the intracellular side
Which type of movement involves phospholipid flipping from one leaflet to the other and is very slow?
Lateral diffusion
Transbilayer diffusion (Flip-Flop)
Facilitated diffusion
Osmosis
Which enzyme moves phospholipids from the outer leaflet to the inner leaflet and uses ATP?
Floppase
Scramblase
Flippase
Kinase
What is the direction of movement for floppase?
Outer → Inner leaflet
Inner → Outer leaflet
Bidirectional exchange
Side-to-side within the same leaflet
Which type of passive transport involves the movement of water?
Simple diffusion
Osmosis
Facilitated diffusion
Transbilayer diffusion
In facilitated diffusion, what happens after the Cl⁻ ion binds to the protein channel?
The protein channel closes
The protein flips, exposing the chloride to the inside of the cell
The protein is degraded
The ion is pumped out of the cell
Which type of movement is described as "fast and frequent" and occurs within the same leaflet?
Transbilayer diffusion
Lateral diffusion
Flippase activity
Osmosis
What is required for catalyzed movement of phospholipids in most cases?
Water
ATP
Oxygen
Glucose
Which protein catalyzes bidirectional exchange of phospholipids and does not require ATP?
Flippase
Floppase
Scramblase
Kinase
During osmosis, water moves from regions of:
High solute (hypertonic) to low solute (hypotonic)
Low solute (hypotonic) to high solute (hypertonic)
High pressure to low pressure
High temperature to low temperature
What is required for active transport to occur in cells?
Energy (usually ATP)
Oxygen
Light
Water
Which pump moves 3 Na⁺ ions out and 2 K⁺ ions into the cell?
Na⁺/K⁺ ATPase pump
H⁺/K⁺ ATPase pump
Ca²⁺/Na⁺ exchanger
SGLT2 transporter
What type of transport moves molecules against their concentration gradient using energy?
Active transport
Passive transport
Filtration
Diffusion
Which of the following is an example of a symporter?
SGLT2 (Na⁺ + glucose into cell)
Na⁺/K⁺ ATPase pump
H⁺/K⁺ ATPase pump
Digoxin
What is the main function of exocytosis?
To move materials out of the cell
To move materials into the cell
To break down proteins
To synthesize DNA
Where are proteins synthesized before being transported in vesicles?
Rough endoplasmic reticulum (ER)
Golgi apparatus
Mitochondria
Lysosome
Which process requires a vesicle with cargo to fuse with the membrane and release contents inside the cell?
Endocytosis
Exocytosis
Filtration
Diffusion
What is the role of the Golgi apparatus in vesicular transport?
Processing vesicles
Synthesizing proteins
Producing ATP
Breaking down waste
What does the term "hypertonic" refer to?
Higher solute concentration
Lower solute concentration
Equal solute concentrations
No solute present
Which type of receptor binds particles coated with IgG antibodies or complement proteins?
Opsonin receptors
Scavenger receptors
Toll-like receptors
Antibodies
What is the main function of phagocytosis?
To engulf and digest target particles
To produce antibodies
To transport oxygen
To synthesize proteins
Which of the following is NOT a step in the phagocytosis process?
Contact
Binding
Photosynthesis
Engulfing
What is the typical intracellular potassium concentration in cells?
~150 mM
~5 mM
~50 mM
~500 mM
Which molecule is a reactive compound that enhances damage by forming other reactive molecules inside the phagolysosome?
Nitric oxide
Antimicrobial peptides
Binding proteins
Antibodies
What is the main role of antimicrobial peptides in the phagolysosome?
Disrupt bacterial membranes
Bind to nutrients
Produce antibodies
Lower pH
Which of the following is true about isotonic solutions?
They have equal solute concentrations on both sides of a membrane.
They have higher solute concentration outside the cell.
They have lower solute concentration inside the cell.
They contain no solutes.
Which enzyme is responsible for actively pumping K+ in and Na+ out of the cell?
Na+/K+ ATPase
DNA polymerase
RNA polymerase
Amylase
What is the net intracellular charge when K⁺ inside is balanced by anions such as proteins, phosphate, and chloride?
Positive
Negative
Neutral
Variable
What type of channels does the membrane have that allow K⁺ to leave the cell?
Sodium-selective leak channels
K⁺-selective leak channels
Calcium-selective leak channels
Chloride-selective leak channels
What happens to the membrane potential when K⁺ efflux increases?
Membrane potential becomes more positive
Membrane potential becomes more negative
Membrane potential stays the same
Membrane potential becomes zero
Which force pushes K⁺ out of the cell during membrane potential development?
Electrical gradient
Concentration gradient
Osmotic pressure
Hydrostatic pressure
At equilibrium, what is true about K⁺ movement across the membrane?
K⁺ movement in is greater than out
K⁺ movement out is greater than in
K⁺ movement in equals out
No K⁺ movement occurs
What is the equilibrium potential for K⁺ (K⁺: ) as given in the material?
+40 mV
0 mV
-92 mV
-70 mV
According to the injection thought experiment, what happens to Vm if only K⁺ permeability exists and the K⁺ concentration gradient is maintained?
Vm always returns to -92 mV
Vm stays at -46 mV
Vm becomes positive
Vm becomes zero
Which two conditions must be met for a membrane potential to exist?
Concentration gradient and temperature
Permeability to K⁺ and membrane thickness
Concentration gradient and permeability to K⁺
Permeability to Na⁺ and membrane thickness
What is the formula for membrane potential (Vm) for monovalent ions as given in the material?
Vm = 61.5 × log([ion]in / [ion]out)
Vm = 61.5 × log([ion]out / [ion]in)
Vm = 58 × log([ion]out / [ion]in)
Vm = 58 × log([ion]in / [ion]out)
What is the formula used to calculate the membrane potential (Vm) for divalent ions such as Ca²⁺?
Vm = (61.5 / z) × log([ion]out / [ion]in)
Vm = (58 / z) × log([ion]in / [ion]out)
Vm = (70 / z) × log([ion]out / [ion]in)
Vm = (61.5 × z) × log([ion]in / [ion]out)
Which ion, when it exits the cell, makes the cell membrane potential negative and close to -92 mV?
Potassium (K⁺)
Sodium (Na⁺)
Chloride (Cl⁻)
Calcium (Ca²⁺)
What is the approximate membrane potential when Na⁺ enters the cell?
+67 mV
-92 mV
-86 mV
+123 mV
In a real cell, what does the resting membrane potential depend on?
Ion concentration gradients and relative permeability of each ion
Only the concentration of potassium ions
The size of the cell
The temperature of the environment
What is the result when the membrane potential calculation is dominated by potassium (K⁺) with 95% permeability?
Membrane potential close to K⁺'s preference
Membrane potential close to Na⁺'s preference
Membrane potential close to Cl⁻'s preference
Membrane potential close to Ca²⁺'s preference
What is exocytosis used for in a cell?
To remove waste or insert proteins into the cell membrane
To break down glucose for energy
To replicate DNA
To transport oxygen
What is a vesicle in the context of exocytosis?
A membrane-bound bubble that encloses material inside the cell
A type of protein channel
A DNA segment
A type of ion
What happens during waste removal via exocytosis?
A vesicle with waste proteins travels to the membrane, fuses, and ejects contents
The cell absorbs nutrients from the environment
The cell divides into two daughter cells
A vesicle forms around incoming material
What is the main function of endocytosis in a cell?
To expel waste from the cell
To bring needed substances into the cell
To produce energy for the cell
To divide the cell into two
Which type of endocytosis is also known as "cell eating"?
Pinocytosis
Receptor-mediated endocytosis
Phagocytosis
Exocytosis
What is a key feature of receptor-mediated endocytosis?
It is non-specific
It uses a lock-and-key recognition system
It only occurs in plant cells
It digests large particles
Which type of cell junction allows direct passage of water, ions, and electrical signals between adjacent cells?
Tight junctions
Desmosomes
Gap junctions
Plasmodesmata
What proteins are gap junctions made of in vertebrates?
Claudins
Connexins
Cadherins
Inexins
Where are tight junctions commonly found?
Cardiac muscle and neurons
Organs like bladder, kidneys, and intestines
Skin and heart muscle
Plant cell walls
Which cell junction acts like "spot welds" and is found in tissues subject to stretching?
Gap junctions
Tight junctions
Desmosomes
Plasmodesmata
What is unique about plasmodesmata compared to other cell junctions?
They are only found in animal cells
They are specialized for plant cells and punch holes through cell walls
They prevent all molecules from passing between cells
They are made of connexin proteins
What can mutations in gap junctions cause?
Ectodermal dysplasia
Skin blistering disorders
Increased hormone action
Enhanced nerve impulses
What is a possible result of desmosome mutations?
Skin blistering disorders
White matter breakdown
Muscle hypertrophy
Enhanced cell division
What is the first step in the signal transduction process?
Ligand binds to a receptor
Intracellular signaling proteins are activated
Cellular response occurs
Receptor undergoes conformational change
What do ligand-gated ion channels convert?
Chemical signal to electrical signal
Electrical signal to chemical signal
Hormone to enzyme
Protein to carbohydrate
Where is the binding site usually located in ligand-gated ion channels?
Extracellular
Intracellular
On the nucleus
On the mitochondria
Which type of receptor is only found in eukaryotes and is the most abundant class?
G-Proteins Coupled Receptors
Ligand-Gated Ion Channels
Voltage-Gated Ion Channels
Enzyme-Linked Receptors
What do G-proteins bind when they are active?
GTP
GDP
ATP
ADP
What is the function of G-Proteins Coupled Receptors?
Regulate smell, taste, vision, and mood
Produce antibodies
Synthesize DNA
Store calcium ions
What happens to the alpha subunit of a G-protein after it exchanges GDP for GTP?
It dissociates from the beta-gamma dimer
It binds to the receptor
It is degraded
It produces ATP
What do target proteins generate in the G-Protein Coupled Receptor mechanism?
Second messengers
Primary messengers
Enzymes
Hormones
What is hydrolyzed to GDP to reset the system in G-protein signaling?
ATP
GTP
cAMP
ADP
Which protein accelerates GTP hydrolysis to turn off the signal in G-protein signaling?
Adenylate cyclase
SH2 protein
RGS protein
Kinase
What is the ligand in the example of adrenergic receptor signaling?
Insulin
Epinephrine
NGF
PDGF
What does adenylate cyclase convert ATP into?
GDP
GTP
cAMP
ADP
What type of proteins are enzyme-linked receptors?
Transmembrane proteins
Cytoplasmic proteins
Nuclear proteins
Extracellular proteins
What is the function of enzyme-linked receptors?
Store genetic information
Speed up biochemical reactions
Transport oxygen
Break down glucose
What is the ligand-binding site of enzyme-linked receptors called?
Intracellular domain
Extracellular domain
Cytoplasmic domain
Nuclear domain
Which of the following is the most common type of enzyme-linked receptor?
G-protein coupled receptor
Receptor tyrosine kinase
Ion channel receptor
Steroid receptor
What do receptor tyrosine kinases (RTKs) phosphorylate to activate signal pathways?
Serine residues
Threonine residues
Tyrosine residues
Histidine residues
What can mutations in RTKs cause?
Diabetes
Cancer
Heart disease
Arthritis
What is the main function of the nucleus in a cell?
DNA storage
Energy production
Lipid destruction
Protein breakdown
Which organelle is responsible for energy (ATP) production in the cell?
Mitochondrion
Lysosome
Golgi Apparatus
Peroxisome
What is the analogy for the Golgi Apparatus in a cell?
Shipping department
Powerplant
Security
Blueprint room
Which organelle is involved in lipid/steroid production and detoxification?
Smooth ER
Rough ER
Nucleus
Lysosome
What is the function of lysosomes in the cell?
Protein breakdown
Energy production
DNA storage
Lipid destruction
What structure surrounds the nucleus and allows molecular exchange?
Nuclear envelope
Cell wall
Plasma membrane
Mitochondrial membrane
Where does transcription (DNA to RNA) occur in the cell?
Nucleus
Cytoplasm
Golgi Apparatus
Mitochondrion
What is the site of ribosome production in the cell?
Nucleolus
Smooth ER
Lysosome
Peroxisome
Which endoplasmic reticulum is studded with ribosomes?
Rough ER
Smooth ER
Golgi Apparatus
Lysosome
What is the main function of peroxisomes?
Lipid destruction and ROS detox
Protein production
DNA storage
Energy production
