We are the chemical messengers that cross the synaptic gaps between neurons. when released by the sending neuron, we travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse. answer 1 we are natural, opiatelike neurotransmitters linked to pain control and pleasure

Neruron is mainly mechanism nervous system.

q: compare the parts of a cell and the cell as a whole to another common nonliving system (i.e., a car, a city,

a:

comparing this to the inside of a food building/company.

plasma membrane - building's walls

all cells are surrounded by a plasma membrane, which protects the cell from its environment, keeping toxic substances out of the cell. it regulates which molecules are allowed to enter and exit the cell.

nucleus - the big boss

regulates all cell activity such as cellular metabolism, and growth in addition to storing and maintaining the cell's dna for transcription and replication. determines what proteins to make.

cytoplasm - working areas

contains the organelles; site of most cell activity

endoplasmic reticulum - engineer's work area

the place where ribosomes do their working activity.

ribosomes - engineers

builds the proteins.

golgi apparatus - pickup truck drivers

prepares proteins for use or export.

lysosomes -   investigators

responsible for breaking down and absorbing materials taken in by the cell.

cytoskeleton - renovators

maintains cell shape.

mitochondria/chloroplasts - materials scientist

transforms one form of energy into another.

Called for cell.