Name: ______Date: ______Class:______
The Stuff you’re Made Of
Chemical Formulas: Determine the chemical formula for the molecule in the picture.
A. Chemical Formula:/ B. Chemical Formula:
/ C. Chemical Formula:
D. Chemical Formula:
/ E. Chemical Formula:
/ F. Chemical Formula:
G. Chemical Formula:
/ H. Chemical Formula:
/ I. Chemical Formula:
1. Compare and contrast molecule A and molecule B in the above pictures.
2. Molecules D and E are exactly the same molecule! They are just drawn slightly differently. What are the 2 different ways to show the end of a carbon chain?
3. Molecules G, H, and I are isomers of each other. What is an isomer?
Chemical Formulas: Determine the chemical formula for the molecule in the picture.
J. Chemical Formula:/ K. Chemical Formula:
/ L. Chemical Formula:
Drawing Skeletal Line Drawings: Make a skeletal line drawing of the following molecules.
C3H8 / C3H6C3H7Br / C3H8O
C5H10Cl2 / C5H8O
Wonder Drugs
Why are skeletal line drawings important? They can be used to represent all sorts of molecules that make up and effect our bodies, and indeed the bodies of all living things. Of particular interest are drugs that alter the normal chemical reactions that occur in the human body. Drug companies are a huge global industry and one of the biggest employers of scientists in the world. These scientists are experts in the language of molecules, the language of skeletal line drawings. It’s these skeletal line drawings that will unlock cures for cancer or powerful longevity drugs. Let’s explore some of the value of skeletal line drawings in comparing the drugs that literally shape our lives.
Bring the Pain
Imagine a world without pain relievers. It would be pretty, well, painful. In 1893 Felix Hofmann, a chemist working at the Bayer company invented aspirin; it proved to be a revolutionary drug. Today aspirin is the most widely used of all drugs for treating illness and injury. There are well over four hundred aspirin-containing drugs, and over forty million pounds of aspirin are produced annually in the US alone! Aspirin is used so widely because it has a wide range of beneficial properties. Not only does it relieve pain, it lowers body temperature, reduces inflammation, and has blood-thinning properties that can prevent heart attacks or strokes.
Ibuprofen is a more recent discovery, being patented in 1961. Its characteristics are somewhat similar to aspirin: it relieves pain, it is an anti-inflammatory, and it reduces fever. Many pain relievers, particularly “extra strength” formulas such as Excedrin, are just a combination of aspirin, ibuprofen, and caffeine. The caffeine not only wakes you up, but it helps in the delivery of the other pain-relieving substances.
Aspirin Ibuprofen
1. What is aspirin’s chemical formula? ______
2. What is ibuprofen’s chemical formula? ______
3. Compare and contrast the chemical structures of these two common pain relievers.
Steroids
Steroids are naturally occurring compounds in the human body. There are hundreds of different kinds, but the most well-known are the steroids involved in human sexual characteristics: testosterone, estrogen, and progesterone. These steroids can be taken as a drug to have a variety of effects. One is the so-called “steroids” that athletes consume to increase muscle mass, a practice often called “doping.” An athlete can take injections of human testosterone, and one of the effects will be an increase in muscle mass. Athletes often don’t take actual testosterone, they take chemicals that are similar, because these chemicals are easier to mass produce, and also the newest chemicals are more likely to go undetected by a drug test.
Another example of a hormone drug is norethindrone, found in the birth control pill. Normally, when a female is pregnant, her body produces high levels of progestrone. These high levels of progesterone tell her body “I’m pregnant, so don’t release any eggs and don’t have a period.” Thus, a female has no periods for 9 months, while the baby grows. How does the birth control pill work? It’s artificial, synthetic progesterone. When a female takes it, she tricks her body into thinking she’s pregnant, so her body doesn’t release any eggs (no eggs, thus no fertilization, thus pregnancy is not possible). The actual drug that a female takes is called norethindrone. Its chemical structure is different than progesterone, but the body can’t tell the difference, so it treats it just like progesterone. The reason is that synthetic progesterone is taken instead of real progesterone is that real progesterone is hard to get (it would have to be extracted somehow from actual females). Norethindrone, on the other hand, comes from a plant, so this plant can be grown on farms, the chemical extracted from the plant in large quantities, and the drug mass-produced.
Progesterone Norethindrone Testosterone
4. What is the chemical formula of progesterone? ______
5. Compare and contrast the chemical structures of progesterone and norethindrone.
6. The birth control pill contains norethindrone, which is synthetic progesterone, so it is meant to mimic the body’s natural progesterone. Why not just have regular progesterone in the birth control pill? Why does the actual birth control pill contain norethindrone?
Antibiotics
You’ve probably taken one of the antibiotics shown below. Penicillin compounds were the first antibiotics discovered and are still used widely today. Antibiotics are drugs that kill bacteria, but they do something special: they don’t kill the person taking the drug at the same time. Antibiotics are chemicals with a rare and unique property: they are toxic only to bacteria, and don’t harm human cells. Most antibiotics come from fungi. For centuries scientists had noticed that fungi tended to repel bacteria, but it wasn’t until the 1940’s that researchers started to successfully harness these chemicals for fighting disease. The first antibiotic, penicillin, was mass produced as a pill shortly before World War II, which saved countless soldiers dying from the bacterial infections that are a result of bullet wounds, burns and other injuries. One of the worrisome results of the widespread use of antibiotics is that bacteria are evolving and becoming resistant to penicillin and other antibiotics. The medical field is running out of things that can fight off bacteria and one day might not have anything!
One thing you will notice about the pictures below is that they contain dark wedges and dashes in the place of some of the normal “sticks” that represent chemical bonds. These are meant to show the molecules in 3D. The wedges are bonds that connect to atoms “in front of the page” and the dashes are bonds that connect to atoms that are “behind the page.” With larger, more complex molecules like this, the 3D orientation of some of the atoms becomes very important in showing the differences between one molecule and another. Remember, molecules are tiny, but they still have space, they still have volume, they still occupy 3D space!
Penicillin-G Ampicillin
Amoxicillin Penicillin-V
7. What do you notice about the chemical structures of these antibiotic molecules that’s different than most other biological molecules we have looked at thus far in biology?
8. What are a few chemical characteristics you can see in the drawings that these antibiotic molecules all have in common?
9. What do antibiotic molecules do that is so uniquely powerful? What do you think could be a reason that fungi naturally make molecules that do this?
10. Molecules tiny, so it is easy to forget that they are actually 3D things. The shape to the right is an attempt to represent a molecule in 3D. What is the chemical formula of this molecule? Draw a 2D skeletal line drawing of this molecule.
M. R. Lawton 2016