How Animals Obtain Energy - Essay Example

After some time, gases are to be collected from the headspace and subjected to mass spectrometric analysis which can separate the CO2 based on their molecular weights. If the oxygen in the carbon dioxide came from the sugar, it will be present in higher concentration at a higher molecular weight (because the labeled 18O will have heavier mass). If the oxygen came from the air, then the reverse would be true.

1. A food manufacturer is advertising a new cake mix as fat-free. Scientists at the U.S. Food and Drug Administration (FDA) are testing the product to see if it truly lacks fat. Hydrolysis of the cake mix yields glucose, fructose, glycerol, several amino acids, and several kinds of molecules with long hydrocarbon chains. Further analysis shows that most of the hydrocarbon chains have a carboxyl group at one end. What would you tell the food manufacturer if you were the spokesperson for the FDA?

If I were the spokesperson of the FDA, I would tell the food manufacturer that his claim of a fat-free mix is downright false. Fats and oils are made up of fatty acids that are anchored on a glycerol backbone. Glycerol is a three-carbon compound with 3 carboxylic groups, each can form an ester bond with a fatty acid. For this reason, fats are also called triacylglycerols. Hydrolysis of fats and oils will yield glycerol and three free fatty acids. The free fatty acids are long-chain hydrocarbon compounds (most common fats have 16-18 carbon atoms) with a carboxyl group (-COO) at one end. Further analysis will even show if these fatty acids are either saturated or unsaturated with hydrogen atoms.

2. Imagine that you are a pediatrician and one of your patients is a newborn who may have a lysosomal storage disease. You remove some cells from the patient and examine them under the microscope. What would you expect to see? Design a series of tests that could reveal whether the patient is indeed suffering from a lysosomal storage disease.

The lysosome is an organelle in the body that processes unwanted material into utilizable substances. This is made possible due to the action of catabolic enzymes. There are forty or more variations of lysosomal storage diseases (LSD), mostly characterized by a deficiency in an enzyme that is essential in the metabolism of lipids, and glycoproteins. Due to this deficiency, substances accumulate in the cell, resulting in cell damage and rupture.  If cells from a diseased patient are collected and examined under the microscope, they will appear to be swollen, while other cells appear striped, depending on the organ which is affected or under study.  The presence of LSD can be checked through genetic tests (for which genetic markers have been developed), enzymatic assays, urine examination for an increased presence of glycosaminoglycans or other lysosomal enzyme substrates, and the use of imaging technologies.

3. Gaining and losing weight is a matter of caloric accounting: Calories in the food you eat minus Calories that you spend in activity. One pound of human body fat contains approximately 3,500 Calories. Using Figure 5.4, compare various ways you could burn off that many Calories. How far would you have to run, swim, or walk to burn the equivalent of 1 pound of fat?  For how much time would you have to do each activity? Which method of burning Calories appeals the most to you? The least?

Figure 5.4        Cheeseburger    295 calories

                                    Bean Burrito 189 calories

Activity

• Running (7 min/mi) = 979 calories burned (food calories consumed per hour by a 150-pound person
• Dancing (fast) =        510 calories burned (food calories consumed per hour by a 150-pound person

A pound of human fat contains 3500 calories. If a person engages in running (7 min/mile), then to burn this many calories, he has to run at that speed for 3.5 hours for a total distance of 31 miles. This figure was arrived at by dividing the number of calories per pound of human fat by the calories burned per hour by that activity.

Thus:   Running          = 3500calories that have to be burned/979

                                     =3.5 hours for a 150-pound person;  or running ~ 31 miles

            Fast dancing:  = 3500 calories that have to be burned/ 510 cal/hour

                                   = 6.86 hours needed to burn 1 lb of fat for a 150-pound person

To burn 1 cheeseburger:

            Running          = 295 calories/979 calories= 0.30 hrs or 18 mins or  ~ 2.6 miles

            Dancing          = 295/510 = 0.58 hour or 35 mins

To burn 1 burrito:

            Running          = 189/979 = 0.19 hour or 12 mins or ~ 1.7 miles

            Dancing          = 189/510= 0.37 hours or 22 mins     

The method which appeals to me most is running, because it gives results in half the time. Dancing appeals to me only if I have a few calories to burn, thus I do not have to dance that long. Running is a much more relaxing exercise for me.