Answer:
The cell wall
Explanation:
The cell wall exists to protect the cell, maintain its shape and regulate water uptake. The cell wall is much thicker than the cell membrane, providing an extra layer of protection. In plants, the cell wall is made of fibres of the polysaccharide cellulose, which is a structural carbohydrate.
This gives organisms such as plants much more structure - e.g. they can stand upright without the need for bones. However, they lack the same flexibility that animal cells have.
Answer:
1. high adaptability
2. low population size
3. All the dinosaurs, along with 50% of all species alive at the time died out when an asteroid struck Earth.
Answer:
Calcium voltage gated ion channels
Explanation:
There are two types of ion channels involved in the neuromuscular junction and end plate potentials: voltage-gated ion channel (responsive to changes in membrane voltage which cause the voltage gated ion channel to open) and ligand-gated ion channel (responsive to certain molecules such as neurotransmitters).
The resting membrane potential of a motor neuron goes from -70mV to -50 with a higher concentration of sodium outside and a higher concentration of potassium inside. <em>When an action potential propagates down a nerve and reaches the axon terminal of the motor neuron, the change in membrane voltage causes the calcium voltage gated ion channels to open allowing for an influx of calcium ions. </em>These calcium ions cause the acetylcholine vesicles to release acetylcholine via exocytosis into the synaptic cleft.
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1. mother to fetus 2. through exposure to the antigen (virus, toxins, or cancer cells).
