Cell Structure and Biophysics Applications

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Questions and Answers

What type of transport does not require metabolic energy?

Simple diffusion (correct)

Ion channel transport

Active transport

Facilitated diffusion (correct)

Which type of transport involves the use of ATP to move substances against their concentration gradient?

Facilitated diffusion

Simple diffusion

Passive transport

Active transport (correct)

What is the function of ion channels in the cell membrane?

To actively transport substances across the membrane

To facilitate simple diffusion

To allow charged ions to move across the membrane (correct)

To maintain the electrical gradient across the membrane

What drives the movement of ions across the cell membrane?

Both electrical and concentration gradients Signup and view all the answers

What is the direction of facilitated diffusion?

With the concentration gradient Signup and view all the answers

What is a characteristic of simple diffusion?

Occurs without assistance Signup and view all the answers

What factor affects cell membrane permeability?

All of the above Signup and view all the answers

What are some of the applications of biophysics?

All of the above Signup and view all the answers

What is the direction of ion movement driven by concentration gradients?

From high to low concentration Signup and view all the answers

What is the main function of the plasma membrane?

To regulate what can pass in and out of the cell Signup and view all the answers

What is the primary component of the plasma membrane?

Lipids (phospholipids and cholesterol) Signup and view all the answers

What is the role of the cell membrane in cell signaling?

It plays an important role in cell signaling and communication Signup and view all the answers

What is the main difference between intracellular and extracellular fluids?

Intracellular fluid has more potassium, phosphate, and proteins Signup and view all the answers

What is the primary mechanism of passive transport?

Moving molecules down their concentration or electrochemical gradient Signup and view all the answers

What is facilitated diffusion?

A type of passive transport that uses a transport protein Signup and view all the answers

What is the main function of simple diffusion?

To move molecules down their concentration gradient Signup and view all the answers

What is the primary reason for the generation of electrical potentials across nerve cell membranes?

The selective permeability of the membrane to certain ions Signup and view all the answers

What is the result of a difference in the concentration of K+ ions on both sides of the membrane?

An electrical potential is generated Signup and view all the answers

What is the typical membrane potential of a living cell?

-70mV Signup and view all the answers

What is the name of the equation that describes the voltage created by the difference in concentration of ions?

Nernst equation Signup and view all the answers

What is the role of the charge on the ion in the Nernst equation?

It is multiplied by the electron charge Signup and view all the answers

What happens to the movement of ions when the membrane potential changes?

It is influenced by the change Signup and view all the answers

What is the state of the cell when the diffusion of high concentration to low concentration is balanced by Coulomb forces?

Resting state Signup and view all the answers

What is the result of the excess positive ions diffusing into the fluid inside the cell?

A negative voltage is generated in the cell Signup and view all the answers

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)

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Description

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.