Proteins, Metabolism Flashcards
are used for anabolic purposes such as synthesis of nonessential amino acids, tissue protein synthesis, enzyme or hormone synthesis, deamination, or transamination.
Absorbed proteins
Amino acid synthesis and degradation are brought about by two reactions called ? that occur in the liver.
transamination and deamination
is the major site of amino acid metabolism
liver
is responsible for nonessential amino acid synthesis
transaminases
The liver has enzymes such as transaminases and is responsible for nonessential amino acid synthesis through a process called
transamination
An amino group from one amino acid is transferred to an ? to form a new amino acid
organic acid
is needed for transaminase activity (transamination)
Vitamin B6 (pyridoxine)
Transamination also provides a link between?
Transamination also provides a link between protein and carbohydrate metabolism, where certain amino acids can use their C skeleton for?
glucose synthesis
is the removal of amino groups from amino acids to form ammonia
Deamination
deamination needed for getting rid of nitrogen from the animal’s body
After deamination or transamination, this part of amino acid are left and are used for making glucose, ketone bodies, or energy production.
C skeleton
is a chemical reaction that transfers an amino group to a keto acid to form new amino acids.
Transamination
All amino acids, except ?, are glucogenic, meaning that they can use the C skeleton for glucose synthesis.
leucine and lysine
are strictly ketogenic amino acids (forms ketone bodies) and can provide acetyl CoA as an energy source.
Leucine and lysine
Since both carbons of acetyl CoA are lost in the tricarboxylic acid (TCA) cycle, it cannot provide?
glucose
is liberated from amino acid degradation is toxic to the central nervous and needs to be excreted or detoxified.
ammonia
Most mammals detoxify ammonia and excrete it as ? in the urine
urea
birds excrete ammonia as?
uric acid
Detoxification of ammonia to urea is through the?
urea cycle
The detoxification of ammonia to form urea is brought about by the urea cycle through two tissues?
liver and kidney
Two nonprotein amino acids involved in the urea cycle are?
ornithine and citrulline
The first step in the urea cycle is the formation of?
carbamoyl phosphate
What reacts with a compound called carbamoyl phosphate and forms citrulline.
Ornithine
Ornithine reacts with a compound called carbamoyl phosphate and forms?
citrulline
Citrulline is easily enters cytosol and reacts with ?, forming argininosuccinate (2 ATP needed).
aspartate
Citrulline is easily enters cytosol and reacts with aspartate, forming?
argininosuccinate
Citrulline is easily permeable and gets into the cytosol and reacts with aspartate, forming argininosuccinate (how many ATP needed).
2
cleaves argininosuccinate into arginine and fumarate
argininosuccinate lyase
fumarate enters?
TCA cycle
Arginine is lysed into ? and splits urea off
ornithine
can be a nonessential amino acid but not available for protein synthesis.
arginine
Is synthesized by the kidney from citrulline
Arginine
The liver breaks down arginine into?
urea and ornithine.
cannot synthesize carbamoyl phosphate and hence they cannot make urea.
Poultry
Instead, glutamic acid, glycine, and methionine are used for?
uric acid synthesis
need high levels of methionine, arginine, and glycine in their diet for optimum production.
poultry
the formation of urea through the urea cycle is dependent on?
ATP dependent
the formation of urea through the urea cycle is ATP dependent, feeding animals poor quality or excess protein is energy demanding and can lead to?
environmental problems
Question: What is the substance produced in the rumen that travels to the liver?
Ammonia (NH3).
Through which blood vessel does ammonia travel to the liver?
Portal vein
What process converts ammonia into urea in the liver?
Urea cycle.
Where does urea go after being produced in the liver?
bloodstream
What are the two possible destinations for urea after it enters the bloodstream?
It can be excreted in urine or sent back to the digestive tract.
This type of synthesis occurs in every tissue of the body
Protein synthesis
Protein synthesis lies ultimately in the?
genetic code.
DNA and RNS consist of?
Nucleotides
contains the genetic code of the animal and is the blueprint of protein synthesis
DNA
DNA controls the formation of?
RNA
Types of RNA:
- Messenger RNA
- Transfer RNA
- Ribosomal RNA
All types of RNA are involved in?
protein synthesis
is the part of the structure of ribosomes, which has three base codons that code for amino acids (site of protein formation).
Ribosomal RNA
picks up specific amino acids from cytoplasm and transports it to the ribosomes (workbench where proteins are made).
Transfer RNA
acts like an adapter during protein synthesis.
Transfer RNA (tRNA)
Each tRNA carries a specific?
amino acid
determines the sequence of amino acids (translation) in the protein formed.
Messenger RNA
Both messenger RNA (mRNA) and tRNA are produced from the?
DNA template
The synthesis of each protein is controlled by a different
mRNA
As the peptide chain is formed, an cannot be formed, which limits the peptide chain formation and protein synthesis
empty space
All 20 amino acids are needed for?
protein synthesis
is a dynamic process involving continuous and simultaneous protein synthesis and protein degradation.
Protein turnover
Constant turnovers of proteins in the body and the loss of proteins, mainly in feces, are the basis for?
protein requirement
Even when an animal is not growing, it still has?
protein requirement
needed in the diet depends on age, physiological (e.g., pregnancy, lactation) and pathological status, and quality of the protein supplied.
amount of protein
