http://www.ck12.org Chapter 3. Chemical Interactions
Protein Functions
Proteins are the most numerous and diverse biochemical compounds, and they have many different functions. Some
of their functions include:
- making up tissues as components of muscle.
- speeding up biochemical reactions as enzymes.
- regulating life processes as hormones.
- helping to defend against infections as antibodies.
- carrying materials around the body as transport proteins (see the example of hemoglobin in theFigure3.73).
FIGURE 3.73
The blood protein hemoglobin binds with
oxygen and carries it from the lungs to
all the body’s cells. Heme is a small
molecule containing iron that is part of
the larger hemoglobin molecule. Oxygen
binds to the iron in heme.Summary
- Proteins are one of four classes of biochemical compounds. Proteins contain carbon, hydrogen, oxygen,
nitrogen, and sulfur. - A protein molecule is made from one or more long chains of amino acids, each linked to its neighbors by
covalent bonds. Multiple chains of a protein are held together by weaker bonds. - Proteins are the most numerous and diverse biochemical compounds. They have many different functions.
Vocabulary
- protein: Biochemical compound that contains oxygen, nitrogen, and sulfur in addition to carbon and hydro-
gen; consists of one or more chains of smaller molecules called amino acids.
Explore More
At the following URL, watch the animation of protein folding and read the description. Then answer the questions
below.
http://intro.bio.umb.edu/111F98Lect/folding.html
- Amino acids with hydrophobic side chains fold toward the center of the protein to avoid __.
- Other amino acids pull the protein into its final shape by forming __ and __ bonds.
- Are these statements true or false?
a. The process of protein folding proceeds by trial and error.