1.
**** TEST QUESTION**** FLAG
____________ is the site where synthesis of UREA occurs.: LIVER
2.
***TEST QUESTION*** FLAG
What is the kidneys way of excreting NH₄⁺ ? (3): 1- Glutaminase releases NH₃ from Gln
2- Glutamate dehydrogenase releases NH₃ from Glu
- NH₃ is excreted into urine as NH₄⁺
3- Kidneys also excrete urea that is produced by the LIVER.
3.
**TEST QUESTION*** FLAG
What is a zwitterions?
How many different R groups are there?: 1- Neutral charge at physiologic pH (7.4) are referred as a zwitterions.
2- 20
4.
1- Can NON-ESSENTIAL amino acids be synthesized by the body?
2- If so, why?: 1- Yes, can be synthesized
2- Because carbon (C-) skeletons can be made adequately from other precursors
5.
1- Disease of AA Metabolism
What happens in Urea Cycle Enzyme Defects? (1)
2- What type of patients will you typically see this in?: 1) Accumulation of NH₃ and intermediates which will lead to neurological and developmental effects
2) Pediatrics
6.
1- How do people obtain ESSENTIAL amino acids? (1)
2- Why are ESSENTIAL AA not synthesized in the body?: 1- Obtained only in the DIET
2- Cannot be synthesized in body because Carbon skeletons (-C-C-C-) are not made or not made in sufficient quantity
7.
1- What are the clinically important transaminases (aminotransferases)? (2)
2- Why are these important? (2): 1- Asparatate aminotransferase (AST)
2- Alanine aminotransferase (ALT)
* both listed above are found in liver cells
2- Serum levels of these enzymes can be measured and used as markers of cellular damage (This will tell us if the liver is damaged)
8.
AA Picture summary: 
9.
Amino acid catabolism: Amino acids cannot be stored in the body and are degraded by liver....
What happens to these amino acids? (3): 1) α- amino groups → UREA and exit via urine
2) C-skeletons are transformed into acetyl CoA and TCA intermediates
3) Some AAs can be converted into:
- ketone bodies (ketogenic AA)
- glucose (glucogenic AA)
10.
Carbon skeletons (C-skeletons) can come from intermediates formed by:: 1- Glycolysis
2- Pentose phosphate pathway
3- TCA cycle
*these all make c-skeltons that make AA's
11.
Disease of AA Metabolism:
1- What happens in Phenylketonuria? (2): 1- There is ↓ enzyme which leads to ↑ [phenlketones]
2- This will cause neurologic deficits
- Eg. Mental retardation
12.
Glutamate is also used to get rid of NH₃ by? (2): 1- The liver (urea)
2- Kidney (NH₄⁺)
13.
How does the body maintain NH₃ homeostasis? (2): 1- Liver converts excess NH₃ into urea which is eliminated by the kidneys
2- The body uses 2 main AA's, Glutamate (Glu) and Glutamine (Gln) to:
a- make use of available NH₃
b- get rid of excess NH₃
14.
How is Glutamate made? (2): 
1- NH₃ (NH₄⁺ in water) can be added to α-ketoglutarate (common C-skelton) to make glutamate.
2- This rxn goes in both directions.
15.
How is glutamine synthesized?: 
Can be synthesized from glutamate
16.
Liver synthesis of urea: 
17.
NH₃ is a necessary substrate but it can also be ________.: TOXIC
18.
Other C-Skeltons get their α-amino group from glutamate by the process of __________________.: Transamination
19.
Source of Amino groups: Amino groups are derived from _______.: Ammonia (NH₃)
20.
There are 5 enzymes involved in the synthesis of urea. Name them and where this occurs: 5 enzymes
1- Carbamoyl phosphate synthetase I
2- Ornithine transcarbamoylase
* both occur in mitochondria
3- Argininosuccinate synthase
4- Argininosuccinase
5- Arginase
* 3 above occur in cytoplasm
21.
Urea Cycle:
1- Urea eliminates ___________ from the body.
2- How is this pathway formed?
3- How does liver disease affect urea synthesis?: 1- Excess nitrogen
2- This pathway is forms urea from NH₃, CO₂, and NH₃⁺ group of aspartate
3- Liver Disease leads to ↓ urea synthesis
- neurologic Sx, coma, and death
22.
What are glutamine's roles? (2): 1- Major AA that circulates in BLOOD.
2- 1⁰ responsible for taking NH₃ form peripheral tissues to kidney where it can be EXCRETED.
23.
What are the Amino Acids (AA) metabolic roles? (2): 1- Building blocks of proteins
2- Precursers of other N-containing substances
24.
What are the Amino Acids metabolic roles; What are the precursors of other N-containing substances (5): 1- Purines and pyrimidines (Eg. DNA, RNA)
2- Porphyrins (Eg. Heme)
3- Creatine (Eg. Muscle)
4- Melanin (Eg. Skin Pigment)
5- Hormones, neurotransmitters
25.
What are the two categories of amino acids (AA)?: Essential and Nonessential
26.
What do NON-ESSENTIAL AA require a source of?: 2- Still require a source of AMINO GROUPS
27.
What does an amino acid ( α-amino and carboxly groups) look like?
(Don't have to know for test, but good for general knowledge): 
** AAs used in nature are "L" stereoisomers (NH₃⁺) on left side of chiral carbon atom
28.
What does transamination do?: 
Transamination uses an enzyme to move the α-amino group from GLY to another carbon skeleton
29.
Will most patients with liver disease have and ELEVATED or DECREASED NH₃?: ...
