36 Questions
What is a key factor that influences the type and magnitude of transport across a membrane?
Thickness and rigidity of the plasma membrane
Which process involves movement of substances against their concentration gradient requiring energy input?
Primary active transport
In which scenario does water move to areas of highest concentration of solute?
When solute concentration is higher outside the membrane
Which of the following is an example of primary active transport?
Sodium-Potassium pump
Which term best describes a solution that has a higher solute concentration compared to the egg's internal environment?
Hyper-osmotic
What is the primary factor that dictates the direction of water movement in osmosis?
Difference in solute concentration across the membrane
If a cell is placed in a solution where the solute concentration is equal to that inside the cell, what term describes this situation?
Iso-osmotic
In passive transport, which process involves molecules moving through a protein channel down their concentration gradient?
Simple diffusion
What is the primary difference between iso-osmotic and hyper-osmotic solutions?
The solute concentration on both sides of the membrane
In the context of osmosis, what is the significance of equilibrium?
It indicates that water movement has stopped
Which scenario best describes a hyper-osmotic solution?
A higher solute concentration on one side of the membrane
If a cell is placed in a solution where the solute concentration is lower than inside the cell, what term describes this situation?
Hypo-osmotic
What is the primary difference between hyper-osmotic and hypo-osmotic solutions?
Hyper-osmotic solutions have higher solute concentration outside the membrane, while hypo-osmotic solutions have higher solute concentration inside the membrane.
Which type of transport mechanism requires an input of energy in the form of ATP?
Active transport
In facilitated diffusion, how do molecules move across the membrane?
With the help of membrane proteins called transporters based on their concentration gradients
If a solution has a higher solute concentration compared to the egg's internal environment, what term describes this situation?
Hyper-osmotic
Which factor primarily influences the type and magnitude of transport across a membrane?
Concentration gradients, membrane permeability, and presence of transport proteins
What differentiates simple diffusion from facilitated diffusion?
Facilitated diffusion involves the movement of molecules based on their concentration gradients with the help of transporters.
In the context of transport mechanisms, what distinguishes a selective membrane from a fully permeable membrane?
A fully permeable membrane only allows water to move across.
Which of the following is an accurate statement regarding osmosis?
Hypertonic solutions attract water causing cell swelling.
Which of the following examples illustrates secondary active transport?
Sodium-glucose linked transporter 2
In the context of membrane transport, what is the primary difference between simple diffusion and facilitated diffusion?
Facilitated diffusion involves the movement of molecules down their concentration gradient through specific membrane proteins, while simple diffusion does not require proteins.
Which of the following scenarios best describes a hyper-osmotic solution?
A solution where the solute concentration is higher outside the cell compared to inside the cell.
Which of the following best represents an example of primary active transport?
Movement of sodium and potassium ions by the sodium-potassium pump.
In a scenario where a cell is placed in a solution with a higher solute concentration, but the solutes cannot pass through the membrane, what will happen to the cell's volume?
The cell's volume will increase.
If a solution with a higher solute concentration is separated by a membrane from an area with lower solute concentration, what kind of movement will occur through the membrane?
Only water will move across the membrane.
Which statement best describes the outcome of diffusion through a fully permeable membrane to both water and solute?
Both water and solutes move freely in any direction across the membrane.
Which of the following examples best represents selective passive transport?
Calcium (Ca2+) ions moving through ligand-gated channels
What is a characteristic of simple diffusion based on the given information?
It enables the diffusion of lipid-soluble molecules like ethanol.
What role do voltage-gated channels play in cellular processes according to the text?
Generating electrical signals for nerve impulse transmission
Which factor is NOT considered when selecting the appropriate transport mechanism for a molecule?
Need for energy input
What distinguishes simple diffusion from diffusion through channels based on the text?
Diffusion through channels is dependent on the membrane's electrical potential.
When considering select passive transport, which of the following is NOT an essential factor to evaluate?
Temperature of the environment
Which factor can influence both active and passive transport mechanisms?
Temperature
What is a characteristic that distinguishes diffusion through channels from simple diffusion?
Is a selective process
When considering factors influencing passive transport, which of the following is NOT typically a primary consideration?
Membrane potential
Study Notes
Cell Membrane Transport
- Cells require a delicate balance between the in- and outflow of ions, nutrients, and waste products to maintain their health and function.
Active and Passive Transport
- There are two primary modes of transport for substances across cell membranes: active transport and passive transport.
- Active transport: energy-driven process that moves molecules against their concentration or electrochemical gradient, requiring cellular energy (ATP).
- Passive transport: does not require energy as substances move along their concentration gradient.
Types of Active Transport
- Primary active transport: involves transmembrane ATPases that directly transport molecules, such as potassium, magnesium, and calcium, against their concentration gradient.
- Secondary active transport: employs the energy stored in electrochemical gradients to transport other molecules against their respective gradients.
Passive Transport Mechanisms
- Simple diffusion: passive movement of molecules across the cell membrane without needing any energy input.
- Facilitated diffusion: requires a transport protein to help molecules move across the membrane.
- Osmosis: special case of passive transport that occurs when water moves across a selectively permeable membrane.
Facilitated Diffusion
- Involves the participation of carrier proteins or channel proteins that bind to specific molecules and transport them across the membrane.
- Selective, as only certain molecules can bind to the carrier or channel proteins.
Simple Diffusion
- Does not require any specific carrier or channel proteins.
- Occurs when small, nonpolar molecules can easily pass through the hydrophobic core of the lipid bilayer by random motion.
Factors Affecting Diffusion
- Concentration gradient: the larger the difference between concentrations, the higher the rate of simple diffusion.
- Molecular size: smaller molecules can pass through cell membranes more easily than larger ones.
- Lipophilicity: lipophilic molecules can pass through lipid bilayer membranes more readily than hydrophilic ones.
- Presence of carrier proteins: some molecules require specific carrier proteins to facilitate diffusion.
Primary Active Transport Examples
- Sodium-potassium pump (Na+/K+-ATPase): maintains the resting membrane potential in excitable cells.
- Calcium pump (Ca2+-ATPase): transports calcium ions out of the cell, maintaining intracellular calcium levels.
- Nutrient transporters: facilitate the transport of essential nutrients, such as glucose and amino acids, against their concentration gradients.
This quiz covers the concepts of active and passive transport, including types and examples like simple diffusion and primary active transport. It also includes an explanation of osmosis and terms like iso-osmotic, hyper-osmotic, and hypo-osmotic. Additionally, the quiz discusses factors influencing transport mechanisms and the differences between passive and active transport through the plasma membrane.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
