Nicotine from cigarette smoke acts as a ligand and associates with specific cells in the nervous system. nicotine eventually produces feelings of pleasure and well-being. below are the events that happen in the cellular response to nicotine. place the events in the correct order to describe the steps in the signaling pathway. a. the acetylcholine receptor is an ion channel, and, when a ligand binds, the ion channel opens. b. an influx of ions carries the signal to the reward areas of the brain. c. nicotine binds to the transmembrane protein that normally binds the neurotransmitter acetylcholine. d. the signal causes release of dopamine in the brain, which causes good feelings. e. nicotine is quickly eliminated from the body (causing cravings for more cigarettes to produce good feelings). c, d, b, a, e a, d, b, c, e nicotine is quickly eliminated from the body (causing cravings for more cigarettes to produce good feelings). c, a, b, d, e b, a, c, d, e

In tossing one coin 10 times, what are your chances for tossing a head? a tail? 2. in tossing one coin 100 times, what are your chances for tossing a head? a tail? 3. in tossing one coin 200 times, what are your chances for tossing a head? a tail? deviation = ((absolute value of the difference between expected heads and observed heads) + (absolute value of the difference between expected tails and observed tails)) divided by total number of tosses. this value should always be positive. 4. what is the deviation for 10 tosses? 5. what is the deviation for the 100 tosses? 6. what is the deviation for 200 tosses? 7. how does increasing the total number of coin tosses from 10 to 100 affect the deviation? 8. how does increasing the total number of tosses from 100 to 200 affect the deviation? 9. what two important probability principles were established in this exercise? 10. the percent of occurrence is the obtained results divided by the total tosses and multiplied by 100%. toss the coins 100 times and record your results. calculate the percent occurrence for each combination. percent head-head occurrence: percent tail-tail occurrence: percent head-tail occurrence:

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates