The cytoplasm of a neuron contains many negatively charged proteins, which give the cell a slightly negative charge at rest. What do you think happens to this charge when the neuron is stimulated?

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.