Membrane Transport

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What is the main function of NCX in many cell types?

Removing Ca2+ ions from plasma membranes, mitochondria, and endoplasmic reticulum (correct)

Promoting the influx of Ca2+ ions

Maintaining Na+ and K+ concentration differences

Inhibiting the transport of Na+ ions

Where is NCKX2 mainly located and what function does it serve?

Neuronal cell membranes - Constituting a Ca2+ clearance mechanism (correct)

Endoplasmic reticulum - Promoting synaptic plasticity

Mitochondria - Regulating memory formation

Plasma membrane - Controlling motor functions

What is the primary role of Na+, K+-ATPase in animal cells?

Maintaining Na+ and K+ concentration differences across the plasma membrane (correct)

Facilitating the influx of Na+ ions

Preventing the transport of K+ ions

Removing Ca2+ ions from mitochondria

Which of the following statements about NCX is true?

It is important for removing Ca2+ ions from the plasma membranes Signup and view all the answers

What role does NCX play in cellular function?

Regulating Ca2+ concentration Signup and view all the answers

What is the main function of leak channels in cells?

Facilitate the flow of ions down the concentration gradient Signup and view all the answers

How do ions pass through the selectivity filter in K+ channels?

By dehydrating and interacting with carbonyl groups Signup and view all the answers

Where are aquaporins most abundant in cells?

Plasma membrane Signup and view all the answers

Which of the following glands predominantly express aquaporins for water secretion?

Sweat glands Signup and view all the answers

What role do hormone-responsive aquaporins play in animals?

Facilitate the formation of concentrated urine Signup and view all the answers

In response to water deficit, what occurs in mammalian cells?

Activation of osmoreceptors Signup and view all the answers

What is the process of a cell taking in fluids and small particles dissolved in it called?

Pinocytosis Signup and view all the answers

Which process involves a cell engulfing a large particle, other cell, or pathogen?

Phagocytosis Signup and view all the answers

What are the cup-shaped lipoprotein structures at the cell plasma membrane called?

Porosomes Signup and view all the answers

Which process involves the release of large quantities of molecules from a cell?

Exocytosis Signup and view all the answers

What is the term for a cell that engulfs pathogens through phagocytosis?

Phagocyte Signup and view all the answers

What factor determines the speed of molecule diffusion across the cell membrane?

Size of the molecule and water association Signup and view all the answers

What contributes to the resting membrane potential of a cell?

Active transport (Na+,K+-ATPase) and passive diffusion Signup and view all the answers

Which ions contribute to the slight excess of positive charge on one side of the cell membrane?

Sodium (Na+) Signup and view all the answers

What does the electrochemical gradient affect in terms of solute transport?

Charged solute transport Signup and view all the answers

Which proteins can associate with the plasma membrane based on their topology?

Proteins containing hydrophilic and hydrophobic regions Signup and view all the answers

What happens to the interior of the cell regarding electrical charge during resting membrane potential?

Turns more negative Signup and view all the answers

What type of transport is simple diffusion?

Passive transport Signup and view all the answers

In simple diffusion, the flow of solutes is always ________.

Down their concentration gradient Signup and view all the answers

Which type of molecules can simply diffuse through the phospholipid bilayer?

Non-charged molecules Signup and view all the answers

Facilitated diffusion involves the movement of molecules through ________.

Membrane channels or carriers Signup and view all the answers

SGLT-1 working through facilitated diffusion is an example of solute transport depending on ________.

The solute's concentration gradient Signup and view all the answers

Passive transport involves movement ________.

Down a solute's concentration gradient Signup and view all the answers

What is the main reason why most polar molecules have restricted passage across the lipid bilayer of the cell membrane?

Hydrophilic nature Signup and view all the answers

Which characteristic of molecules plays a significant role in determining their permeability across the cell membrane?

Molecular weight Signup and view all the answers

What is the primary function of transport proteins in the cell membrane?

Transport of molecules and ions Signup and view all the answers

In the context of membrane transport, what distinguishes channels from transport proteins (carriers)?

Channels selectively allow specific ions or molecules to pass through Signup and view all the answers

Which type of diffusion involves the use of specific membrane proteins to facilitate the movement of molecules across the plasma membrane?

Facilitated diffusion Signup and view all the answers

What is the primary characteristic of active transport that distinguishes it from passive transport mechanisms?

Moves molecules against their concentration gradient Signup and view all the answers

What contributes to the resting membrane potential of a cell?

Passive diffusion of K+ ions into the cell Signup and view all the answers

How does the electrochemical gradient affect solute transport?

It influences the movement of charged solutes Signup and view all the answers

What type of molecules can associate with the plasma membrane based on their topology?

Proteins containing hydrophilic and hydrophobic regions Signup and view all the answers

What is the main role of Na+,K+-ATPase in animal cells in the context of membrane potential?

Maintaining the electrical charge imbalance across the membrane Signup and view all the answers

Which process primarily results in the interior of the cell becoming more negative during resting membrane potential?

Passive movement of negatively charged ions into the cell Signup and view all the answers

How does the size and association with water affect molecule diffusion across the membrane?

Smaller, less associated with water molecules diffuse more rapidly Signup and view all the answers

What is a distinguishing feature between channels and transporters in terms of solute interaction?

Channels interact more weakly with solutes compared to transporters Signup and view all the answers

What is the state where transporter binding sites are not accessible for solutes?

Occluded state Signup and view all the answers

What is the main function of gated ion channels?

Convert mechanical stimuli to chemical or electrical signals Signup and view all the answers

In which state of transporter proteins are the binding sites exposed to the outside?

Outward-open state Signup and view all the answers

What conversion do mechanosensitive channels perform?

Convert mechanical stimuli to chemical or electrical signals Signup and view all the answers

How do transporters differ from channels in terms of solute transfer?

Transporters undergo conformational changes for solute transfer, while channels do not Signup and view all the answers

What type of transport requires energy and is always mediated by transporters (carrier)?

Active transport Signup and view all the answers

Which type of transporter can be classified based on the direction of transport?

Uniport Signup and view all the answers

What type of transporter moves 2 molecules in the opposite direction?

Antiporter Signup and view all the answers

Which type of active transport is driven by a gradient generated by another active transporter?

Secondary active transport Signup and view all the answers

In endocytosis, what is surrounded by an area of plasma membrane to form a vesicle inside the cell?

Ingested material Signup and view all the answers

Which transporter works against the solute's concentration gradient and usually requires energy from ATP?

Na⁺/K⁺ ATPase Signup and view all the answers

What is the primary function of porosomes at the cell plasma membrane?

Act as secretory portals for molecules to be released Signup and view all the answers

Which process involves a cell exporting molecules such as neurotransmitters and proteins?

Exocytosis Signup and view all the answers

What distinguishes phagocytosis from pinocytosis in terms of the substances taken in by the cell?

Size of particles engulfed Signup and view all the answers

What is the main function of phagosomes in the context of cellular processes?

Engulf large particles during phagocytosis Signup and view all the answers

In exocytosis, what structures at the cell plasma membrane are involved in releasing intra-vesicular contents?

Porosomes Signup and view all the answers

What is a common characteristic of transport proteins?

Bind substrates at different locations through the membrane Signup and view all the answers

Which type of transporter removes calcium from cells?

Na+/Ca2+ exchanger Signup and view all the answers

How do most membrane proteins cross the lipid bilayer?

In a helical conformation Signup and view all the answers

What distinguishes the Na+/Ca2+ exchanger in terms of energy usage?

Utilizes energy stored in sodium electrochemical gradient Signup and view all the answers

Where does the Na+/Ca2+ exchanger transport calcium ions?

3 out of the cell and 1 Na+ into the cell Signup and view all the answers

What is a common structural feature of transport proteins?

Accessible substrate binding sites on both sides of the membrane simultaneously Signup and view all the answers

Which type of membrane transport protein forms pores for solutes to move across the membrane?

Channels Signup and view all the answers

In which state of transporters are the binding sites for solutes exposed to the inside of the cell?

Inward-open state Signup and view all the answers

What is the primary difference between channels and transporters in terms of solute interaction?

Transporters interact more strongly with solutes. Signup and view all the answers

Gated ion channels convert mechanical stimuli into which type of signals?

Electrical Signup and view all the answers

Which state of transporters indicates that the binding sites for solutes are not accessible?

Occluded state Signup and view all the answers

What distinguishes transport proteins from channels in terms of solute transfer?

Transport proteins transfer solutes more actively. Signup and view all the answers

What is the main function of aquaporins in cells?

Facilitation of osmotic water flow Signup and view all the answers

How does the size of ions affect their passage through the selectivity filter of K+ channels?

Smaller ions are not recognized in the filter Signup and view all the answers

Which type of glands predominantly express aquaporins to facilitate water secretion?

Sweat glands Signup and view all the answers

What causes an increase in the expression of aquaporins in the kidneys' collecting ducts?

Increase in water deficit Signup and view all the answers

How do leak channels differ from gated ion channels?

Leak channels are always open, while gated channels are essentially closed Signup and view all the answers

What distinguishes aquaporins that are hormone-responsive in animals?

They play a role in urine concentration Signup and view all the answers

What type of transport involves the movement of molecules against the solute's concentration gradient and usually requires energy from ATP?

Active transport Signup and view all the answers

Which of the following is a characteristic feature of primary active transporters?

Saturable kinetics like enzymes Signup and view all the answers

What is the term used for transporters that move 2 molecules in opposite directions?

Antiporters Signup and view all the answers

Which type of active transport is driven by a gradient generated by a primary active transporter?

Secondary active transport Signup and view all the answers

How does passive transport differ from active transport?

It involves movement of molecules down their concentration gradient Signup and view all the answers

What is the main difference between passive simple diffusion and channel-mediated transport?

Involvement of membrane proteins Signup and view all the answers

How does facilitated diffusion differ from simple diffusion?

Involves carrier proteins Signup and view all the answers

What determines the direction of transport in facilitated diffusion?

Electric potential across the membrane Signup and view all the answers

Which type of molecules are able to diffuse through the phospholipid bilayer in passive simple diffusion?

Small or non-charged molecules Signup and view all the answers

What distinguishes passive facilitated diffusion from active transport?

Requirement of energy Signup and view all the answers

Membrane Transport

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Questions and Answers

What is the main function of NCX in many cell types?

Where is NCKX2 mainly located and what function does it serve?

What is the primary role of Na+, K+-ATPase in animal cells?

Which of the following statements about NCX is true?

What role does NCX play in cellular function?

What is the main function of leak channels in cells?

How do ions pass through the selectivity filter in K+ channels?

Where are aquaporins most abundant in cells?

Which of the following glands predominantly express aquaporins for water secretion?

What role do hormone-responsive aquaporins play in animals?

In response to water deficit, what occurs in mammalian cells?

What is the process of a cell taking in fluids and small particles dissolved in it called?

Which process involves a cell engulfing a large particle, other cell, or pathogen?

What are the cup-shaped lipoprotein structures at the cell plasma membrane called?

Which process involves the release of large quantities of molecules from a cell?

What is the term for a cell that engulfs pathogens through phagocytosis?

What factor determines the speed of molecule diffusion across the cell membrane?

What contributes to the resting membrane potential of a cell?

Which ions contribute to the slight excess of positive charge on one side of the cell membrane?

What does the electrochemical gradient affect in terms of solute transport?

Which proteins can associate with the plasma membrane based on their topology?

What happens to the interior of the cell regarding electrical charge during resting membrane potential?

What type of transport is simple diffusion?

In simple diffusion, the flow of solutes is always ________.

Which type of molecules can simply diffuse through the phospholipid bilayer?

Facilitated diffusion involves the movement of molecules through ________.

SGLT-1 working through facilitated diffusion is an example of solute transport depending on ________.

Passive transport involves movement ________.

What is the main reason why most polar molecules have restricted passage across the lipid bilayer of the cell membrane?

Which characteristic of molecules plays a significant role in determining their permeability across the cell membrane?

What is the primary function of transport proteins in the cell membrane?

In the context of membrane transport, what distinguishes channels from transport proteins (carriers)?

Which type of diffusion involves the use of specific membrane proteins to facilitate the movement of molecules across the plasma membrane?

What is the primary characteristic of active transport that distinguishes it from passive transport mechanisms?

What contributes to the resting membrane potential of a cell?

How does the electrochemical gradient affect solute transport?

What type of molecules can associate with the plasma membrane based on their topology?

What is the main role of Na+,K+-ATPase in animal cells in the context of membrane potential?

Which process primarily results in the interior of the cell becoming more negative during resting membrane potential?

How does the size and association with water affect molecule diffusion across the membrane?

What is a distinguishing feature between channels and transporters in terms of solute interaction?

What is the state where transporter binding sites are not accessible for solutes?

What is the main function of gated ion channels?

In which state of transporter proteins are the binding sites exposed to the outside?

What conversion do mechanosensitive channels perform?

How do transporters differ from channels in terms of solute transfer?

What type of transport requires energy and is always mediated by transporters (carrier)?

Which type of transporter can be classified based on the direction of transport?

What type of transporter moves 2 molecules in the opposite direction?

Which type of active transport is driven by a gradient generated by another active transporter?

In endocytosis, what is surrounded by an area of plasma membrane to form a vesicle inside the cell?

Which transporter works against the solute's concentration gradient and usually requires energy from ATP?

What is the primary function of porosomes at the cell plasma membrane?

Which process involves a cell exporting molecules such as neurotransmitters and proteins?

What distinguishes phagocytosis from pinocytosis in terms of the substances taken in by the cell?

What is the main function of phagosomes in the context of cellular processes?

In exocytosis, what structures at the cell plasma membrane are involved in releasing intra-vesicular contents?

What is a common characteristic of transport proteins?

Which type of transporter removes calcium from cells?

How do most membrane proteins cross the lipid bilayer?

What distinguishes the Na+/Ca2+ exchanger in terms of energy usage?

Where does the Na+/Ca2+ exchanger transport calcium ions?

What is a common structural feature of transport proteins?

Which type of membrane transport protein forms pores for solutes to move across the membrane?

In which state of transporters are the binding sites for solutes exposed to the inside of the cell?

What is the primary difference between channels and transporters in terms of solute interaction?

Gated ion channels convert mechanical stimuli into which type of signals?

Which state of transporters indicates that the binding sites for solutes are not accessible?

What distinguishes transport proteins from channels in terms of solute transfer?

What is the main function of aquaporins in cells?

How does the size of ions affect their passage through the selectivity filter of K+ channels?

Which type of glands predominantly express aquaporins to facilitate water secretion?

What causes an increase in the expression of aquaporins in the kidneys' collecting ducts?

How do leak channels differ from gated ion channels?

What distinguishes aquaporins that are hormone-responsive in animals?

What type of transport involves the movement of molecules against the solute's concentration gradient and usually requires energy from ATP?