A.AS #2 Flashcards
(40 cards)
What are essential amino acids?
Amino acids that can’t be synthesized by the body.
Must be supplied in the diet (e.g., Phe, Trp, Val, Leu, Ile, etc.).
What are semi-essential amino acids?
Amino acids synthesized but insufficient during high demand.
Examples: Arg, Cys during growth, illness, or pregnancy.
What are non-essential amino acids?
Amino acids synthesized sufficiently by the body.
Examples: Glu, Asp, Ala, Pro, Ser, etc.
Which amino acids are purely ketogenic?
Lysine and Leucine.
Produce only ketone bodies.
What are glucogenic and ketogenic amino acids?
Amino acids that produce both glucose and ketone bodies.
Examples: Trp, Ile, aromatic AAs.
What is the function of pepsin in protein digestion?
Breaks down proteins into smaller peptides.
Activated in the stomach by HCl.
What enzymes are secreted by the pancreas for protein digestion?
Trypsin, chymotrypsin, elastase, carboxypeptidase.
Activated in the small intestine.
What is acute pancreatitis?
A condition where pancreatic enzymes activate prematurely.
Damages pancreatic tissue and can be fatal.
How are amino acids absorbed in the intestine?
By sodium-dependent active transport and diffusion.
Small neutral and aromatic AAs use specific transporters.
What is the gamma-glutamyl cycle’s role in amino acid transport?
Facilitates absorption of amino acids using glutathione.
Requires ATP and glutathione.
What are the main sources of free amino acids in the body?
Diet, body synthesis, and protein degradation.
Maintain the amino acid pool for various uses.
What is the largest use of the amino acid pool?
Protein synthesis in the body.
Also used for synthesizing compounds like GABA, histamine, etc.
What is histamine synthesized from?
Histidine by decarboxylation.
What are histamine blockers used for?
To treat allergies and acid reflux.
Examples: Diphenhydramine (allergy), Cimetidine (acid reflux).
What is nitric oxide synthesized from?
Arginine.
What is the function of nitric oxide (NO)?
Acts as a signaling molecule in the body.
Regulates vasodilation, neurotransmission, and blood clotting.
What are the neurotransmitters derived from tyrosine?
Dopamine, epinephrine, norepinephrine, and thyroxine.
What is the cause of maple syrup urine disease?
Defect in branched-chain ketoacid dehydrogenase.
Leads to accumulation of Val, Leu, Ile and metabolic acidosis.
What is the main symptom of albinism?
Lack of melanin synthesis.
Caused by a defect in tyrosinase or tyrosine-3-monooxygenase.
What is homocystinuria caused by?
Deficiency of cystathionine beta-synthase.
Results in high homocysteine and methionine, low cysteine levels.
What is the defect in phenylketonuria (PKU)?
Phenylalanine hydroxylase deficiency.
Causes phenylalanine accumulation; managed by dietary restriction.
What is the function of GABA?
Acts as an inhibitory neurotransmitter.
What are the nitrogen derivatives of glycine?
Heme, purines, creatine.
What enzyme is deficient in alkaptonuria?
Homogentisate-1,2-dioxygenase.
Leads to dark urine and ochronosis (pigment accumulation).
