Biochemistry 2- Boards & Beyond Flashcards
What amino acids do histones have a high content of
Lysine, arginine
What substitution occurs with sickle cell anemia
Polar glutamate for nonpolar valine
What are the 2 strictly ketogenic amino acids
Leucine, lysine
What is the cofactor for phenylalanine hydroxylase
BH4 (tetrahydrobiopterin)
What is the order of tyrosine metabolism
Tyrosine, DOPA, dopamine, norepinephrine, epinephrine
What enzyme is deficiency in oculocutaneous albinism
Tyrosinase
What is deficient in alkaptonuria
Homogentisic acid oxidase
What is the classic findings with alkaptonuria
Dark urine when left standing, arthritis, black pigment in cartilage/joints (calcification in IV discs), urine discoloration in children, dark pigment
What are common serotonin effects in carcinoid syndrome
Diarrhea (serotonin stimulates GI motility), increased fibroblast growth and fibrogenesis (leading to valvular lesions), flushing
What is the issue with Hartnup disease and how is it inherited
Absence of AA transport in proximal tubule; autosomal recessive
What are some common symptoms with Hartnu disease
Pellets (hyperpigmented rash, exposed areas of skin, red tongue, diarrhea, dementia)
What are the branched chain Amino acids
Valine, leucine, isoleucine
What is the deficiency in maple syrup urine disease and what are some symptoms
Deficiency of alpha keto acid dehydrogenase; increased branched chain AAs and alpha-ketoacids in plasma; neurotoxicity is main problem, urine smells sweet
What are some common symptoms of homocystinuria
Lens dislocation, long limbs, chest deformities, osteoporosis in childhood, blood clots, early atherosclerosis
What is the alanine cycle used fr
By the muscles to transfer nitrogen to liver
What is the rate limiting enzyme in the urea cycle
Carbamoyl phosphate synthetase I
What is the most common defect in urea cycle
Ornithine transcarbamylase
What is another name for vitamin B1
Thiamine
What is the term for thiamine deficiency not associated with alcohol and how does it present
Beriberi; dry has polyneuritis, muscle weakness; wet has tachycardia, high-output heart failure, edema
What is another name for vitamin B2
Riboflavin
What vitamin is required for synthesis of niacin from tryptophan
Vitamin B6
What are the 4 Ds associated with niacin deficiency
Pellagra: dermatitis, diarrhea, dementia, death
What is another name for vitamin B5 and what is it used in
Pantothenic acid; coenzyme A
What is another name for vitamin B6
Pyridoxal phosphate
What type of anemia can occur with vitamin B6 deficiency
Sideroblastic anemia (because iron cannot be incorporated into heme and so it accumulates in RBC cytoplasm)
What is the only B vitamin with potential toxicity
B6
What is biotin (vitamin B7) cofactor for
Carboxylation enzymes
What vitamin is required for conversion of dopamine to norepinephrine
Vitamin C
What vitamin can be in excess with sarcoidosis
Vitamin C
What deficiency should you think of with impaired sexual development, poor wound healing, and loss of taste
Zinc
What heredity are most lysosomal storage diseases
Autosomal recessive
What is deficient in fabry’s disease, what accumulates
Alpha-galactosidase A is deficient; ceramics trihexoside accumulates
What is the classic case seen with Fabry’s disease
Child with pain in hands/feet, lack of sweat, skin findings (angiokeratomas)
What is deficient in gaucher disease and who is it most common in
Deficiency of glucocerebrosidase; ashkenazi Jews
What should you think of with crinkled paper macrophages
Gaucher disease
What is the common presentation of gaucher disease
Hepatosplenomegaly, severe bone pain, easy bruising from low platelets, join problems
What is deficient with Niemann pick disease
Acid sphingomyelinase
What is the classic case of Niemann pick disease
Previously well/healthy child, weakness/loss of motor skills, enlarged liver or spleen on physical exam, cherry red spot
What are some conditions that commonly have cherry red spot
Niemann-pick, tay-Sachs, central retinal artery occlusion
What is deficient with Krabbes disease
Galactocerebroside
What is the classic case of Krabbes disease
Presents at 6 months, only neuro symptoms, progressive weakness, absent reflexes
What is deficient with Tay Sachs and what accumulates
Deficiency of hexosaminidase A; GM2 ganglioside accumulates
What is the presentation of Tay Sachs
Presents 3-6 months, weakness, exaggerates startle reaction, progresses to seizures/vision/hearing loss, cherry red spot, NO hepatosplenomegaly
What is the classic Path finding with Tay Sachs
Lysosomes with onion skinning
What is the deficiency with metaochromatic leukodystrophy
Arylsulfatase A
What are common presentations of metachromatic leukodystrophy
Roughly 2 years old, ataxia, hypotonia
What is deficient with Hurler’s syndrome and what accumulates
Deficiency of alpha-L-iduronidase; accumulation of heparin and dermatan sulfate
What are some symptoms of hurler’s syndrome
Corneal clouding, coarse facial features, short stature, hepatosplenomegaly
What is the heredity of hunters syndrome
X-linked recessive
What is deficient with Hunter’s syndrome
Iduronate-2-sulfatase
What makes hunter’s syndrome different from hurlers
No corneal clouding, later onset, behavioral problems, learning difficulty, trouble sitting still, often aggressive behavior
