Proteins, Digestion and Absorption Flashcards
is the process by which ingested feed is broken down physically and chemically to simple products for absorption from the digestive tract.
Digestion
involves the denaturing of peptide bonds and the release of free amino acids.
Protein digestion
Protein-digesting enzymes are either?
endopeptidase or exopeptidase
This enzyme break peptide bonds within the primary structure into smaller fragments.
Endopeptidases
This enzyme cleave amino acids off the terminal end of the protein molecule.
Exopeptidases
This enzyme remove an amino acid from the end with a free carboxyl group
Carboxypeptidases
This enzyme act on the terminal amino acid with a free amino group.
aminopeptidase
Protein digestion begins in the?
stomach
This hormone, initiates the breakdown of proteins in the stomach.
Gastrin
presence of food in the stomach leads to the secretion of ? by the chief cells of the gastric mucosa.
pepsinogen
The presence of food in the stomach leads to the secretion of pepsinogen by ? of the gastric mucosa
the chief cells
This pepsinogen turns into ?, which is active, thanks to hydrochloric acid (HCl) made by another type of cell called parietal cells.
pepsin
This pepsinogen turns into pepsin, which is active, thanks to?
hydrochloric acid (HCl) made by parietal cells.
What type of enzyme is pepsin?
Endopeptidase
In young animals, what enzyme is released in the stomach to help clot milk, making it easier to move into the small intestine.
rennin
the second stage of protein digestion occurs in the?
small intestine
is a hormone released in the small intestine (duodenum) that stimulates the pancreas to release certain enzymes
Secretin
Secretin is a hormone released in the small intestine (duodenum) that stimulates the pancreas to release certain enzymes, what are does inactivate form of enzymes?
trypsinogen, chymotrypsinogen, and procarboxypeptidase
Another substance in the duodenum called ? activates trypsinogen, turning it into trypsin
enterokinase
Another substance in the duodenum called enterokinase activates trypsinogen, turning it into?
trypsin
After activation of trypsin it then then converts chymotrypsinogen and procarboxypeptidase to their active forms which are?
chymotrypsin and carboxypeptidase.
What is the activated enzyme that plays a very crucial role in protein digestion in the small intestine?
Trypsin
Digestion is finished off by other enzymes including ? from mucosal membranes.
aminopeptidases and dipeptidases
absorption of proteins is facilitated by the?
villi within the small intestine into the bloodstream
Proteins that are transported via active transport, requiring energy, and use of sodium as a kind of cotransported molecule
Normal free proteins
Protein that use a direct transport method that does not require energy.
Whole proteins
These organic compounds are the main type absorbed into the bloodstream
Free amino acids
small chains of amino acids, like ?can also be taken in the circulatory system
di-, tri-, and oligopeptides
are specific to different types of amino acids based on their characteristics, like whether they are neutral, basic, or acidic, and whether they are large or small.
Carrier proteins
When our body absorbs amino acids, it prefers the ? over D-forms.
L-forms (the natural ones)
could be used for tissue protein, enzyme, and hormone synthesis and deamination or transamination, and the carbon skeleton can be used for energy.
Absorbed amino acids
in the hindgut are subjected to microbial fermentation leading to the production of ammonia and other polyamines.
Undigested proteins
in ruminant animals, dietary proteins are classified as?
rumen degradable and rumen undegradable proteins
In ruminants (like cows), the microbes in their stomach use proteins as a source of?
nitrogen
Microbes need nitrogen to build their own?
microbial protein
Microbes do not “care” where the nitrogen sources come from and can use nonprotein nitrogenous substances such as urea for?
microbial protein synthesis
is 100% degradable in the rumen by microbial urease (can be toxic at higher levels).
Urea
Urea is 100% degradable in the rumen by microbial called?
urease
Protein entering the rumen may be degraded by both bacteria and protozoa, which produce?
proteolytic enzymes
The rumen microbes provide ? to cleave peptide bonds in polypeptides to release the free amino acids from proteins.
proteases and peptidases
Several factors such as solubility and the physical structure of protein can affect?
rumen degradation
These rumen-degraded amino acids release NH3 and the C skeleton by a process called?
deamination
synthesize their own microbial protein
rumen microbes
which serves as a primary source of protein to the host ruminant animals.
microbial protein
is enough for maintenance and survival but not for high-producing animals.
Microbial protein
Ammonia absorbed from rumen is converted to urea and secreted into the blood as?
blood urea nitrogen (BUN)
can be filtered and recycled to the rumen via saliva or through the rumen wall
Urea
The concentration of blood urea nitrogen (BUN) in ruminants reflects the efficiency of?
protein utilization.
Not all proteins are degraded in the
rumen
Proteins that are not degraded by rumen microbes are called?
escaped, “bypassed,” or “undegradable” (rumen undegradable protein, RUP)
have a low rumen degradation rates (e.g. proteins in corn).
escaped, “bypassed,” or “undegradable” (rumen undegradable protein, RUP)
“bypassed,” or “undegradable” (rumen undegradable protein, RUP) enters the ? of the ruminant animal for digestion and absorption
abomasum and small intestine
Proteins reaching the small intestine could be
RUP or microbial proteins
The amino acid needs of the host animal are met by?
RUP and microbial proteins.
cannot be stored within the body, so a constant dietary supply of it is necessary
amino acids
Monogastric or Ruminants: The amino acid profile in the small intestine matches their diet.
Monogastric
Monogastric or Ruminants: The amino acid profile in the small intestine is different from their diet.
Ruminants
Monogastric or Ruminants: They cannot improve low-quality dietary protein.
Monogastric
Monogastric or Ruminants: They can upgrade low-quality dietary protein.
Ruminants
Monogastric or Ruminants: High-quality protein remains high-quality after digestion.
Monogastric
Monogastric or Ruminants: High-quality protein can become lower in quality after digestion.
Ruminants
Monogastric or Ruminants: They cannot use non-protein nitrogen sources like urea.
Monogastric
Monogastric or Ruminants: They can use non-protein nitrogen sources like urea.
Ruminants
Monogastric or Ruminants: A constant supply of amino acids is required for their bodily functions.
Both
Among the cereal grains, this grains contain has the highest bypass potential. However, it should be noted that it is deficient in essential amino acids such as lysine and methionine.
corn
Which essential amino acids are deficient in corn?
Lysine and methionine.
Name two animal protein sources with high bypass potential.
Fish meal and meat meal.
What processing methods increase the bypass potential of feed?
Drying forages and heat treatment
tend to denature the feed protein due to the generation of heat, thereby “protecting” the protein from lysis in the rumen.
Feed processing methods
sources that remain intact in the rumen and dissolve in the abomasum are commercially available.
Rumen protected protein
