Lecture 5 - Nitrogen Metabolism Part 1 Flashcards
where are amino acids obtained from
dietary proteins, body protein degradation or new synthesised protein
what are amino acids used for
synthesise proteins and other nitrogen containing compounds or generate energy
what contribute to the amino acid pool
dietary proteins, body proteins and amino acid synthesis all contribute to the amino acid pool
what can amino acids be split into and forms
the ammonia group is removed, we are left with the carbon backbone which forms a keto acid
what are non essential amino acids
amino acids that are synthesised in the body
what are essential amino acids
they are needed in the diet as we do not have the enzymes to make them
what is special about the amino acid arginine and why
it is considered an essential but also a non essential amino acid
because under certain physiological states there is a high demand for this amino acid
what is an example of a time that we need more arginine than we can produce
during an active growing period we need this amino acid in the diet because our ability to produce it is not enough to keep up with the demands
what are some important regulators of metabolism that amino acids are precursors for
- catecholamines
- thyroid hormones
what are important regulatory molecules that amino acids are precursors for
- serotonin (neurotransmitter)
- melatonin (sleep)
- nitric oxide (very important vasodilator)
creatinine is derived from what and where
derived by spontaneous cyclisation of creatine and creatine phosphate in skeletal muscle
where is creatine phosphate made
made in the muscle
what is creatine phosphate a fast supplier of
fast supplier of phosphate to make ATP from ADP
what is creatinine levels in the blood a good marker of
kidney function : high levels of creatinine in the blood indicates the clearance by the kidneys is poor
what are urine creatinine levels proportional to
proportional to muscle mass
- creatinine is formed in muscle, so the more muscle you have the more there will be in your urine
amino acid carbon skeletons can be … or …
carbon skeletons can be glucogenic or ketogenic
what is meant by a glucogenic carbon skeleton
an amino acid that can lead to a carbon backbone in the citric acid cycle can be used to make glucose so therefore is glucogenic
what is meant by a ketogenic carbon skeleton
an amino acid that can be broken down into acetyl CoA or ketone body is ketogenic
what is the major product in urine
urea
what are the nitrogen containing products that are excreted in urine
- urea
- ammonia
- uric acid
- creatinine
what is nitrogen balance a measure of
a measure if nitrogen input versus output
what is nitrogen balance
when nitrogen intake equals nitrogen excretion
what is positive nitrogen balance
when nitrogen intake is greater than nitrogen excretion
what are the possible causes of positive nitrogen balance
- childhood and adolescent growth
- pregnancy
- body building
what are the possible causes of negative nitrogen balance
- injury
- surgery
- infection
- starvation
What would be the likely Nitrogen Balance status of an individual on a high protein diet
should be in balance, nitrogen can not be stored so the excess consumed will be excreted
What would be the likely Nitrogen Balance status of an individual on anabolic steroids
positive, they cause muscle growth so utilization of amino acids not degradation
What would be the likely Nitrogen Balance status of an individual on a diet deficient in essential amino acids
negative, limited protein synthesis cause missing some amino acids, so increased degrading
