CK-12 Physical Science - For Middle School

http://www.ck12.org Chapter 9. Chemistry of Carbon

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/5092

FIGURE 9.19

Glycine is one of 20 common amino acids that make up the proteins of

living things.

Protein Functions

Proteins are the most common biochemicals. They have many different functions, including:

• making up tissues as components of muscle.


• speeding up biochemical reactions as enzymes.


• regulating life processes as hormones.


• helping defend against infections as antibodies.


• transporting materials as components of the blood (see the example inFigure9.20).

FIGURE 9.20

The blood protein hemoglobin binds with

oxygen and carries it from the lungs to

cells throughout the body. Heme is a

small molecule containing iron that is part

of the larger hemoglobin molecule. Oxy-

gen binds to the iron in heme.