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Can oxygen diffuse across a cell membrane?
No, oxygen cannot directly diffuse across a cell membrane. Instead, it crosses the cell membrane with the help of specific transport proteins, such as aquaporins and oxygen channels. These proteins facilitate the movement of oxygen from areas of high concentration to low concentration.
What are 2 substances that diffuse freely across a cell membrane?
CO2, H2O, and O2 can all diffuse across a cell membrane. Also, small polar molecules (uncharged) and hydrocarbons easily diffuse across.
Why can oxygen diffuse across a cell membrane but a protein?
Its too large
Describe how synapses work?
The action potential reaches the pre synaptic area, which opens a voltage sensitive Calcium ion gate, allowing calcium ions to move in via diffusion along an electrochemical gradient. The period of refraction (repolarisation) closes this gate. The increased conc. of Calcium ions pushes vesicles with neurotransmitter to the presynaptic membrane, where they fuse and exocytosis causes the neurotransmitter to be released across the synaptic cleft. The NT binds to a receptor which opens Na+ channels on the postsynaptic membrane, allowing depolarisation due to Na+ diffusion which continues the action potential across the other neurone. The neurotransmitters are broken down by enzymes or are reabsorbed by endocytosis into the presynaptic cleft, using energy from ATP.
What is a presynaptic neuron?
a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body or one or more dendrites of a postsynaptic neuron by the release of a chemical neurotransmitter.
The transport mechanism for a neurotransmitter across the synaptic cleft is called?
The transport mechanism for a neurotransmitter across the synaptic cleft is called exocytosis. During exocytosis, neurotransmitter-filled vesicles fuse with the presynaptic membrane, releasing the neurotransmitter into the synaptic cleft where it can then bind to receptors on the postsynaptic membrane.
What does the neurotransmitter bind to after it moves across the synaptic cleft?
The neurotransmitter binds to specific receptors on the postsynaptic neuron's membrane. This binding triggers a series of events that can either excite or inhibit the postsynaptic neuron, ultimately influencing its activity.
How plasma membrane diffuse across plasma membrane?
Ions can't diffuse across membranes, they must used channels to transport across
What kinds of molecules freely diffuse across a semipermeable membrane?
Water molecules freely diffuse across a semipermeable membrane.
How do you use diffuse in sentence?
Oxygen molecules diffuse across the membrane.
The condition that produces inhibition at a synapse is called what?
Neurotransmitters diffuse across the synaptic cleft (a very short distance) and bind to receptor proteins on the postsynaptic membrane. Excitatory neurotransmitters cause sodium ions to move through receptor proteins depolarizing the membrane. Inhibitory neurotransmitters do not depolarize the postsynaptic membrane. Thus, the condition that would produce inhibition at synapse is called HYPERPOLARIZATION.
What is the membrane said to be if a substance is able to diffuse across a membrane?
selectively permeable
If a substance is able to diffuse across a membrane then the membrane is said to be what?
selectively permeable
Communication across a synapse is initiated by the release of a neurotransmitter from what region of the neuron?
Communication across a synapse is initiated by the release of a neurotransmitter from the axon terminal of the presynaptic neuron. When an action potential reaches the axon terminal, it triggers the influx of calcium ions, leading to the fusion of neurotransmitter-containing vesicles with the presynaptic membrane. This process causes the neurotransmitters to be released into the synaptic cleft, where they bind to receptors on the postsynaptic neuron and facilitate communication.
If a substance is unable to diffuse across a membrane we say the membrane is?
osmotically active
Can oxygen diffuse across a cell membrane?
No, oxygen cannot directly diffuse across a cell membrane. Instead, it crosses the cell membrane with the help of specific transport proteins, such as aquaporins and oxygen channels. These proteins facilitate the movement of oxygen from areas of high concentration to low concentration.
What are 2 substances that diffuse freely across a cell membrane?
CO2, H2O, and O2 can all diffuse across a cell membrane. Also, small polar molecules (uncharged) and hydrocarbons easily diffuse across.
