Study Set Content:
Protein digestion and absoprtion mechanical digestion(chewing)
MOUTH
Protein digestion and absoprtion denaturation(HCl) enzymatic digestion(pepsin)
stomach
Protein digestion and absoprtion Enzymatic digestion(chymotrypsin, trypsin, proteases), absortion of amino acids, di- and tripeptides
Small intestines
Unless you are eating it raw, the first step in digesting an egg (or any other solid food) is
chewing.
begin the mechanical breakdown of large egg pieces into smaller pieces that can be swallowed.
teeth
secrete saliva to aid swallowing and the passage of the partially mashed egg
salivary glands
The salivary glands secrete saliva to aid swallowing and the passage of the partially mashed egg through the
esophagus
PROTEIN DIGESTION IN THE STOMACH The mashed egg pieces enter the (blank) from the esophagus
stomach
The stomach releases gastric juices containing hydrochloric acid and the enzyme,
pepsin
Muscular contractions, called
peristalsis
• Muscular contractions, called peristalsis, also aid in digestion. The powerful stomach contractions churn the partially digested protein into a more uniform mixture, which is called
chyme
Mechanical digestion
peristalsis
Chemical digestion of proteins
Acid + pepsin = gastric juices
In the stomach, proteins are denatured because of the acidity of
hydrochloric acid.
• Because of the hydrochloric acid in the stomach, it has a very low pH of
1.5-3.5
• Because of the hydrochloric acid in the stomach, it has a very low pH of 1.5-3.5. The acidity of the stomach causes food proteins to
denature
Because of the hydrochloric acid in the stomach, it has a very low pH of 1.5-3.5. The acidity of the stomach causes food proteins to denature, unfolding their three-dimensional structure to reveal just the
polypeptide chain.
• Once proteins are denatured in the stomach, the peptide bonds linking amino acids together are more accessible for
enzymatic digestion
That process is started by
pepsin
Once proteins are denatured in the stomach, the peptide bonds linking amino acids together are more accessible for enzymatic digestion. That process is started by pepsin, an enzyme that is secreted by the cells that line the stomach and is activated by hydrochloric acid. Pepsin begins breaking peptide bonds, creating shorter
polypeptides
