| Question |
Answer |
| What is the cause of PKU |
deficiency in phenylalanine hydroxylase (PAH) |
| Why is PKU a problem |
PHE is elevated in tissues, plasma and urine it gets converted into phenylketones. High PHE decreases brain levels of other aromatic AA in brain |
| What are the symptoms of PKU |
mental retardation, failure to walk or talk, seizures, tremor, and microcephaly |
| How common is PKU allele in US and why is it not a problem in the womb |
1 in 50, mother clears the Phe in the fetus. Because of this testing cannot not be done right after birth but should be done at second feeding |
| What is the treatment for PKU and how long should it continue |
low protein, low PHE diet that has to start 7-10 days after birth to avoid mental retardation. must follow diet for life |
| What is maple syrup urine disease |
recessive disorder deficiency of branched-chain a-ketoacid dehydrogenase (BCAKD) Accumulation of Leu, Ile, and Val and their corresponding a-keto acids in blood causes toxic effect on the brain
|
| Symptoms of Maple syrup urine disease |
vomiting, dehydration, severe metabolic acidosis with no treatment disease leads to mental retardation, physical disabilities, and death |
| What are the types of maple syrup urine disease |
Classic type- no BCAKD activity severe acidosis in first week of life.
Intermediate type- 4-5% of normal enzyme activity can be treated with large doses of thiamine. |
| What is the treatment of Maple syrup urine disease |
giving Leu, Ile, and Val in low doses in diet. need to be tested within first 24 hours and start treatment to continue normal development |
| What is Albinism |
it is deficiency in melanin production can be autosomal dominant, recessive,or x linked. Complete albinism is from deficiency of tyrosinase activity |
| What are the two types of melanine and their sub types |
Eumelanin (most abundant)- Black and Brown Pheomelanin has a pink to red hue. |
| What are mongolian spots |
birthmark results from entrapment of melanocytes in the dermis. normally a blue, black or brown mark. |
| What is Homocystinuria |
autosomal recessive disease with high plasma and urine levels of Met and homocysteine. Homozygous patients can have mental retardation and arterial disease |
| What is treatment for homocstinuria |
Low methionine diet with supplementation with vit B12 and B6 and folate which can help metabolize Met. |
| What is the major cause of death for people with homocystinuria |
about 25% die of myocardial infarction before age 30 |
| What is Alkaptonuria |
black urine disease rare 1 in 1 million, they have high homogentisic acid, large joint arthritis, and black pigmentation of cartilage. Caused by deficiency in homogentisate oxidase |
| What is the treatment of Alkaptonuria |
no treatment late in life once you have the associated arthritis you just have to suffer. Can be prevented with nitisionone insectiside that inhibits homogentisic acid. |
| What are nonesential amino acids (definition not list) |
AA that can be synthesized by us |
| What are essential amino acids |
AA that can not be synthesized and we get them from the diet |
| Why are AA acids broken down? |
carbon skeletons give seven intermediate products used in sythesis of glucose and lipids. Production of energy by oxidizing them in the TCA cycle |
| Which amino acids are strictly ketogeneic |
Leucine, Lysine |
| Which AA can be both keto-genic and glycogenic |
Phenylalanine, Isoleucine, tyrosine, and Tryptophan. |
| AA that yield pyruvate or the intermediates of TCA cycle are called? |
Glycogenic or glucogenic the give rise to glucose or glycogen formation |
| AAA acids that yield acetoacetate or its precursors (acetyl or acetoaacetyl-CoA) are called what type of AA |
Ketogenic give rise to ketone bodies |
| Homocystein can be converted into two AA name them and the cofactor needed for the conversion |
Homocystein to Methionine needs Folate & Vit B12
Homocystein to Cystein needs Vit B6 |
| What is the role of folic acid in AA metabolism |
It is a source of one carbon unit along with methanol, formaldehyde, formic acid and carbonic acid |
| What are the two carbon carriers in AA metabolism |
Tetrahydrofolic acid and S-adenosylmethionine(SAM) |
| What makes the active form of Folic Acid (THF) |
Dihydrofolate reductase |
| List the 9 essential amino acids |
His, Iso, Leu, Lys, Met, Phe, Thr, Trp, Val |
| Beans are a good source of which essential amino acds |
Lysine and Thr |
| Rice is a good source of which essential AA |
Met |
| What is Kwashiorkor |
childhood malnutrition due to insufficient protein uptake |
| How are the non essential AA made |
Made from intermediates of metabolism |
| Except Tyr, Phe, and Cys was is required for AA synthesis |
Sulfur from Met |
| Which nonessential AA is considered essential during childhood because the body cannot convert enough for growth |
Arg |
| What is transamination |
Transfer of amino group to alpha keto acids. Ala, Asp, Glut. each has their own transferase ie ALT |
| What is the only AA from glycolisis |
Ser |
| What are the consequences of defects in AA metabolism |
mental retardation and developmental abnormalities. |
| How are AA metabolism defects detected |
Through screening of new borns generally 10 to 20 markers are tested for abnormalities |
Max Smith
on 2009-07-17
500 Words
