24 Questions
What type of transport does not require metabolic energy?
Simple diffusion
Which type of transport involves the use of ATP to move substances against their concentration gradient?
Active transport
What is the function of ion channels in the cell membrane?
To allow charged ions to move across the membrane
What drives the movement of ions across the cell membrane?
Both electrical and concentration gradients
What is the direction of facilitated diffusion?
With the concentration gradient
What is a characteristic of simple diffusion?
Occurs without assistance
What factor affects cell membrane permeability?
All of the above
What are some of the applications of biophysics?
All of the above
What is the direction of ion movement driven by concentration gradients?
From high to low concentration
What is the main function of the plasma membrane?
To regulate what can pass in and out of the cell
What is the primary component of the plasma membrane?
Lipids (phospholipids and cholesterol)
What is the role of the cell membrane in cell signaling?
It plays an important role in cell signaling and communication
What is the main difference between intracellular and extracellular fluids?
Intracellular fluid has more potassium, phosphate, and proteins
What is the primary mechanism of passive transport?
Moving molecules down their concentration or electrochemical gradient
What is facilitated diffusion?
A type of passive transport that uses a transport protein
What is the main function of simple diffusion?
To move molecules down their concentration gradient
What is the primary reason for the generation of electrical potentials across nerve cell membranes?
The selective permeability of the membrane to certain ions
What is the result of a difference in the concentration of K+ ions on both sides of the membrane?
An electrical potential is generated
What is the typical membrane potential of a living cell?
-70mV
What is the name of the equation that describes the voltage created by the difference in concentration of ions?
Nernst equation
What is the role of the charge on the ion in the Nernst equation?
It is multiplied by the electron charge
What happens to the movement of ions when the membrane potential changes?
It is influenced by the change
What is the state of the cell when the diffusion of high concentration to low concentration is balanced by Coulomb forces?
Resting state
What is the result of the excess positive ions diffusing into the fluid inside the cell?
A negative voltage is generated in the cell
Study Notes
Biophysics Applications
- Data analysis and structure
- Computer modeling
- Molecules in motion
- Neuroscience
- Bioimaging
- Medical applications
Cell Structure
- Cells have three main parts: plasma membrane, cytoplasm, and nucleus
- Plasma membrane: thin, flexible barrier separating cell interior from outside environment
- Plasma membrane components: lipids (phospholipids and cholesterol), proteins, and carbohydrate groups
Plasma Membrane Functions
- Protects cell interior
- Provides support and maintains cell shape
- Regulates cell growth through endocytosis and exocytosis
- Plays a role in cell signaling and communication
- Acts as a selectively permeable membrane
Fluid Composition
- Intracellular fluid: high in potassium, phosphate, and proteins
- Extracellular fluid: high in sodium and chloride ions, with smaller concentrations of proteins
- Solute and ion gradients maintain fluid equilibrium and membrane electrical potential
Membrane Transport
- Passive transport: molecules move down concentration or electrochemical gradient
- Types of passive transport: simple diffusion, facilitated diffusion, and osmosis
- Active transport: molecules move against concentration gradient, using ATP energy
Ion Channels and Movement
- Ion channels: proteins that allow charged ions to move across the membrane
- Concentration and electrical gradients drive ion movement
- Ion diffusion is a passive process, no energy required
- Electrical gradients can drive ion movement
Factors Affecting Cell Membrane Permeability
- Cell membrane composition
- Temperature
- pH of surrounding environment
- Polarity, electric charge, and molecular mass of molecules passing through the membrane
Electrical Signals and Ion Movement
- Electrical potentials are generated across nerve cell membranes due to ion concentration differences
- Ion movement down concentration gradients generates electrical potential
- Membrane potential: -70mV, with negative inside and positive outside
- Changes in ion movement or membrane potential influence each other
Resting State and Nernst Equation
- Resting state: equilibrium between ion diffusion and Coulomb forces
- Nernst equation: calculates voltage created by concentration differences
- Equation: Voltage = (kT/Ze) * ln(Cin/Cout)
Learn about the main components of a cell, including the plasma membrane, cytoplasm, and nucleus, and explore various applications of biophysics, such as data analysis, computer modeling, and medical applications.
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