51 Questions
What is the direction of molecule movement in diffusion?
From area of high concentration towards area of low concentration
What is the function of the plasma membrane?
To restrict the movement of some substances
Which type of transport uses cellular energy (ATP)?
Active transport
What is the name of the process by which ions (Na+, K+, Ca2+) pass through the plasma membrane?
Channel mediated diffusion
What is the result of osmosis on a cell?
An increase in internal water volume
What drives the process of simple diffusion?
Concentration gradient
What type of substances can pass through the plasma membrane by simple diffusion?
Small molecules (O2, CO2) or lipid soluble particles
What is the function of ATP in the cell?
To serve as the primary energy source for the cell
What is the characteristic of the hydrophilic head of a phospholipid molecule?
It is polar and faces the outside of the plasma membrane
What is the main function of integral proteins in the plasma membrane?
To facilitate transport across the plasma membrane
What is the definition of salts in the context of biology?
Compounds that dissociate in water into ions
What is the main function of peripheral proteins in the plasma membrane?
To regulate cell signaling pathways
What is the definition of ions in the context of biology?
Charged particles that are formed when salts dissociate in water
What is the fluid that surrounds the cell and is in contact with the plasma membrane?
Interstitial fluid
What is the main reason why many solutes cannot diffuse across the plasma membrane?
They are not lipid-soluble
What type of solution has a solute concentration greater than that inside the cell?
Hypertonic
Which of the following is an example of a primary active transport process?
Na+/K+ pump
What is the result of a red blood cell being placed in a 10% NaCl/ 90% H2O solution?
The cell will shrink
What is the purpose of the Na+/K+ pump in a cell?
To maintain a higher concentration of potassium in the cytoplasm
What is the primary function of the Na+/K+ pump?
To maintain a higher concentration of K+ in the cytoplasm
Which type of transport involves the infolding of the plasma membrane to form a vesicle?
Endocytosis
What is the difference between active and passive transport?
Active transport moves substances against the concentration gradient, while passive transport moves with it
What is the result of a red blood cell being placed in a 0.1% NaCl/ 99.9% H2O solution?
The cell will swell
What is the primary difference between phagocytosis and pinocytosis?
Phagocytosis involves the transport of solids, while pinocytosis involves the transport of liquids
What is the direction of molecule movement in exocytosis?
From the cytoplasm to the extracellular fluid
What is the energy source used to drive vesicular transport?
ATP
What is the purpose of the Na+/K+ pump in maintaining ion balance?
To maintain a balance of Na+ and K+ ions across the plasma membrane
Which type of transport does not use ATP?
Passive transport
What is the term for the transport of substances into the cell using vesicles?
Endocytosis
What is the term for the transport of substances out of the cell using vesicles?
Exocytosis
What is the primary function of vesicular transport?
To transport molecules across the plasma membrane
What is the result of a cell being placed in a hypotonic solution?
The cell will gain water and swell.
What is the purpose of primary active transport?
To move solutes against their concentration gradient.
What is the result of a cell being placed in an isotonic solution?
The cell will maintain its shape and size.
What is the purpose of the Na+/K+ pump?
To maintain the proper balance of Na+ and K+ ions.
What is the characteristic of primary active transport?
It uses ATP to drive the transport of solutes.
What is the primary function of the Na+/K+ pump in maintaining ion balance?
To generate a concentration gradient of Na+ and K+ ions across the plasma membrane
What is the primary characteristic of the plasma membrane that allows it to regulate the movement of substances?
Selective permeability
Which type of diffusion is facilitated by the shape change of carrier molecules?
Carrier-mediated diffusion
Which type of vesicular transport involves the infolding of the plasma membrane to form a vesicle?
Endocytosis
What is the energy source used to drive vesicular transport?
ATP
What is the primary function of ATP in the context of cellular transport?
To provide energy for the transport of ions across the plasma membrane
What is the result of a higher concentration of water outside a cell compared to inside the cell?
The cell will swell
What is the primary difference between phagocytosis and pinocytosis?
Phagocytosis involves the transport of solids, while pinocytosis involves the transport of liquids
What is the driving force behind the movement of molecules in passive transport?
Concentration gradient
Which of the following molecules is NOT an example of a protein?
CaCO3
Which type of transport process is driven by the concentration gradient of molecules across the plasma membrane?
Passive transport
What is the characteristic of the hydrophobic tail of a phospholipid molecule?
Nonpolar and uncharged
Which type of molecule can pass through the plasma membrane unassisted during simple diffusion?
Lipid-soluble molecules
What is the fluid that surrounds the cell and is in contact with the plasma membrane in the bloodstream?
Plasma
Which of the following is an example of a peripheral protein?
Receptor protein
Study Notes
The Plasma Membrane
- Composed of a phospholipid bilayer with cholesterol, integral proteins, and peripheral proteins
- Phospholipid molecule has a hydrophilic (polar) head and a hydrophobic (nonpolar) tail
- Integral proteins are embedded within the phospholipid bilayer, while peripheral proteins are found on the surface
Transport across the Membrane
- Occurs between extracellular fluid, interstitial fluid, plasma, and intracellular fluid
- Types of transport: passive (no energy input from the cell) and active (uses cellular energy, e.g. ATP)
Terminology
- Salts: compounds that dissociate in water into ions (e.g. NaCl, CaCO3, KCl)
- Ions: charged molecules (e.g. Na+, K+, Ca2+, Cl-)
- Proteins: complex molecules present in the body (e.g. hormones, enzymes, antibodies, collagen, keratin, hemoglobin)
- ATP: primary energy source for the cell, made by mitochondria
- Solute: substance being dissolved
- Solvent: substance that dissolves the solute (e.g. water)
Passive Processes
- Simple diffusion: unassisted passage of small molecules (e.g. O2, CO2) or lipid-soluble particles, driven by concentration gradient
- Facilitated diffusion: channel-mediated diffusion allows passage of ions (e.g. Na+, K+, Ca2+), driven by concentration gradient
- Carrier-mediated diffusion: shape change to transport sugars, amino acids, and other substances through the membrane, driven by concentration gradient
- Osmosis: movement of solvent (water), driven by concentration gradient, can change the shape of a cell
Osmosis
- Isotonic solution: same solute concentration as inside the cell
- Hypertonic solution: greater solute concentration than inside the cell, leading to less water (solvent)
- Hypotonic solution: lower solute concentration than inside the cell, leading to more water (solvent)
Active Processes
- Uses cell energy (ATP) to drive movement of solutes across the plasma membrane, against concentration gradient
- Primary active transport: ATP is used to drive transport of substances across the plasma membrane (e.g. Na+/K+ pump)
- Vesicular transport: molecules or particles are transported across the plasma membrane in vesicles, using ATP to drive movement
Vesicular Transport
- Endocytosis: transport substances into the cell, infolding of the plasma membrane fuses to create a vesicle (e.g. phagocytosis for solids, pinocytosis for liquids)
- Exocytosis: transport substances out of the cell, vesicle fuses with plasma membrane and releases contents
The Plasma Membrane
- Composed of a phospholipid bilayer with cholesterol, integral proteins, and peripheral proteins
- Phospholipid molecule has a hydrophilic (polar) head and a hydrophobic (nonpolar) tail
- Integral proteins are embedded within the phospholipid bilayer, while peripheral proteins are found on the surface
Transport across the Membrane
- Occurs between extracellular fluid, interstitial fluid, plasma, and intracellular fluid
- Types of transport: passive (no energy input from the cell) and active (uses cellular energy, e.g. ATP)
Terminology
- Salts: compounds that dissociate in water into ions (e.g. NaCl, CaCO3, KCl)
- Ions: charged molecules (e.g. Na+, K+, Ca2+, Cl-)
- Proteins: complex molecules present in the body (e.g. hormones, enzymes, antibodies, collagen, keratin, hemoglobin)
- ATP: primary energy source for the cell, made by mitochondria
- Solute: substance being dissolved
- Solvent: substance that dissolves the solute (e.g. water)
Passive Processes
- Simple diffusion: unassisted passage of small molecules (e.g. O2, CO2) or lipid-soluble particles, driven by concentration gradient
- Facilitated diffusion: channel-mediated diffusion allows passage of ions (e.g. Na+, K+, Ca2+), driven by concentration gradient
- Carrier-mediated diffusion: shape change to transport sugars, amino acids, and other substances through the membrane, driven by concentration gradient
- Osmosis: movement of solvent (water), driven by concentration gradient, can change the shape of a cell
Osmosis
- Isotonic solution: same solute concentration as inside the cell
- Hypertonic solution: greater solute concentration than inside the cell, leading to less water (solvent)
- Hypotonic solution: lower solute concentration than inside the cell, leading to more water (solvent)
Active Processes
- Uses cell energy (ATP) to drive movement of solutes across the plasma membrane, against concentration gradient
- Primary active transport: ATP is used to drive transport of substances across the plasma membrane (e.g. Na+/K+ pump)
- Vesicular transport: molecules or particles are transported across the plasma membrane in vesicles, using ATP to drive movement
Vesicular Transport
- Endocytosis: transport substances into the cell, infolding of the plasma membrane fuses to create a vesicle (e.g. phagocytosis for solids, pinocytosis for liquids)
- Exocytosis: transport substances out of the cell, vesicle fuses with plasma membrane and releases contents
Learn about the plasma membrane, a crucial component of the cellular level of organisation. This quiz covers the anatomy and functions of the plasma membrane in cells.
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