Analyzing Data
You Are What You Eat
Organisms get energy from the food they eat, but the energy contained in foods varies greatly. Most foods contain a combination of proteins, carbohydrates, and fats. One gram of protein or a carbohydrate such as glucose contains roughly 4 Calories. One gram of fat, however, contains about 9 Calories. The accompanying table shows the approximate composition of one serving of some common foods.
Interpret Data Per serving, which of the foods included in the table has the most protein? Which has the most carbohydrates? Which has the most fat?
Calculate Approximately how many more Calories are there in 2 slices of bacon than there are in 3 slices of roasted turkey? Why is there a difference?
Calculate Walking at a moderate pace consumes around 300 Calories per hour. At that rate, how many minutes would you have to walk to burn the Calories in one chocolate bar? (Hint: Start by calculating the number of Calories consumed per minute by walking.)
Overview of Cellular Respiration
What is cellular respiration?
If oxygen is available, organisms can obtain energy from food by a process called cellular respiration. Cellular respiration is the process that releases energy from food in the presence of oxygen. Although cellular respiration involves dozens of separate reactions, an overall chemical summary of the process is remarkably simple:
As you can see, cellular respiration requires oxygen and a food molecule such as glucose, and it gives off carbon dioxide, water, and energy. Do not be misled, however, by the simplicity of this equation. If cellular respiration took place in just one step, all of the energy from glucose would be released at once, and most of it would be lost in the form of light and heat. Clearly, a living cell has to control that energy. It can't simply start a fire—the cell has to release the explosive chemical energy in food molecules a little bit at a time. The cell needs to find a way to trap those little bits of energy by using them to make ATP.
In Your Notebook Do plants undergo cellular respiration? What organelle(s) do they have that helps you determine the answer?
FIGURE 9–1 A Controlled Release Cellular respiration involves a series of controlled reactions that slowly release the energy stored in food. If the energy were to be released too suddenly, most of it would be lost in the forms of light and heat—just as it is when a marshmallow catches fire.
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis