42 Questions
What is the fluid-like portion of cytoplasm that contains dissolved substances?
Cytosol
What is the function of the plasma membrane?
To act as a selectively permeable barrier
What type of proteins penetrate through the plasma membrane?
Integral proteins
What is the main component of the lipid bilayer?
Phospholipids, sphingolipids, and cholesterol
What is the effect of double bonds in the lipid bilayer?
It makes the bilayer more flexible
Which substances can pass through the plasma membrane?
Gases, alcohol, and small, nonpolar substances
What is the purpose of water channels in the plasma membrane?
To allow the passage of water
What type of proteins are attached only to one surface of the plasma membrane?
Peripheral proteins
What is the direction of movement of water in osmosis?
From higher to lower water concentration
What is the effect of increasing molecular weight on diffusion?
Decreases diffusion
What is the effect of increasing temperature on diffusion?
Increases diffusion
What is the effect of increasing concentration gradient on diffusion?
Increases diffusion
What is the effect of increasing lipid solubility on diffusion?
Increases diffusion
What is the effect of increasing resistance on diffusion?
Decreases diffusion
What is osmotic pressure (π) related to?
The amount of pressure required to stop osmosis
What determines the osmotic pressure (π) of a solution?
The number of osmotically active particles
What is the primary driving force behind the movement of substances from one point to another in a system?
Concentration difference
What type of gradients can contribute to the flow of substances?
Concentration and electrical gradients
What is the basis for diffusion?
Energy gradient
What determines the rate of diffusion?
Resistance of flow
What is the equation that describes the rate of diffusion?
𝐽 =− 𝐷𝐴 ∆𝐶 ∆𝑋
What type of movement is described by Fick's Law of Diffusion?
Constant, random movement
What is the term for the movement of substances through the cell membrane?
Diffusion
What determines the direction of diffusion?
Concentration gradient
What is the direction of transport of K+ ions in the figure?
Against the concentration gradient
Why does H+ ion concentration move against the gradient in the figure?
Because it is more abundant in the lumen
What is the characteristic of primary active transport?
Pumps molecules against the concentration gradient
What is the function of an antiporter?
Transports substances in opposite directions
What is the correct statement about the cell membrane?
It is a selectively permeable barrier that regulates the transport of molecules
What is false about the rate of osmosis?
It is affected only by the pressure gradient
Which statement is false about passive transport?
It moves solutes against their concentration gradient
What is the correct statement about the sodium-potassium pump?
It requires integral proteins
What is a characteristic of the cell membrane?
It is selectively permeable
What is the result of double-bonded fatty acids in the lipid bilayer?
Increased flexibility of the membrane
What is a type of transport mechanism that requires energy input?
Active transport
What is an example of a transport mechanism that does not require energy input?
Simple diffusion
What is a way to classify transport mechanisms?
By number of solutes transported
What is the function of the smooth ER?
Lipid synthesis
What is a characteristic of passive transport?
Does not require energy input
What is the result of active transport?
Movement of solutes with energy input
What is an example of a transport mechanism that moves solutes against their concentration gradient?
Active transport
What is a characteristic of the lipid bilayer?
Contains double-bonded fatty acids
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