22 Questions
What type of transport does not require the cell to expend energy?
Simple diffusion
In ligand-gated ion channels, what triggers the opening of the channel for ion transport?
A change in membrane potential
Which type of transport moves molecules against an energy gradient?
Primary active transport
What role do carriers or transporters play in facilitated diffusion?
Bind with molecules or ions and assist in their transport
At the neuromuscular junction, what initiates the release of acetylcholine into the synaptic cleft?
Action potential in the motor neuron
Secondary active transport differs from primary active transport in that it:
Does not directly use cellular energy
What type of proteins are responsible for facilitated diffusion of sugars, amino acids, and nucleosides?
Carrier proteins
Which statement is true about facilitated diffusion?
The rate of diffusion is proportional to the concentration of the diffusing substance.
What is one key characteristic of carrier proteins in facilitated diffusion?
They are specific in the substrates they act upon.
In facilitated diffusion, what determines the maximum rate of transport?
The number of carrier proteins available in the membrane.
Which type of transport pathway best describes carrier proteins in facilitated diffusion?
Uniport
How do carrier proteins differ from channel proteins in facilitated diffusion?
Channel proteins undergo conformational changes to facilitate transport.
What are the ions that are important for cellular reactions and the operation of cellular control mechanisms?
Potassium, magnesium, phosphate
What is the main function of membrane potential in excitable cells?
Transmit electrochemical impulses
Which protein is responsible for controlling fluidity and permeability in the lipid bilayer?
Cholesterol
Which organelle is responsible for synthesizing new protein molecules in cells?
Endoplasmic reticulum
What is the main function of peroxisomes in cells?
Synthesis of bile acids
In which type of transport do sodium molecules move against their concentration gradient?
Secondary active transport
What is the process by which ligand-gated ion channels open in response to a specific molecule binding?
Signal transduction
Action potential in the neuromuscular junction is primarily due to the influx of which ion?
$Na^+$ (Sodium)
Primary active transport involves the direct use of cellular energy, usually in the form of:
ATP hydrolysis
What happens to water-soluble substances when they encounter a lipid bilayer?
They are usually unable to penetrate.
Test your knowledge on integral membrane proteins, their role in transport, and molecular structure. Explore the alternative pathways and functions of carriers/transport proteins in facilitating substance movement across the lipid bilayer.
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