Essentials of Anatomy and Physiology

clotting; albumin to maintain blood volume; pepsin
and amylase for digestion; growth hormone and
insulin; and the thousands of enzymes needed to cat-
alyze reactions within the body.
The amino acids we obtain from the proteins in
our food are used by our cells to synthesize all of these
proteins in the amounts needed by the body. Only

when the body’s needs for new proteins have been

met are amino acids used for energy production. But

notice in Fig. 17–4 what happens to excess amino

acids; they will be deaminated and converted to simple

carbohydrates and contribute to glycogen storage

or they may be changed to fat and stored in adipose

tissue.

Body Temperature and Metabolism 407

Proteins

(enzymes, structural)

Non-essential

amino acids

Transamination

Proteins

(Digestion)

Amino

acids

NH 2

C

C

NH 2

NH 2

C

C

C

C

C

C

C C CCCC

CCC

CCCCC C CC

CCCCCCC C

(Digestion) (Digestion)

Glucose

Glycerol

Fatty acid

Carbohydrates Fats

Phospholipids

(cell membranes)

Pentose sugars

Excess

(deamination)

Excess

Glycogen

True fats

(adipose tissue)

Cholesterol

and other

steroids

Figure 17–4. Synthesis uses of foods. See text for description.

QUESTION:Excess amino acids can be used to synthesize carbohydrates or fats. Can any

other food be used to synthesize proteins?