Biochemistry Flashcards
Williams syn
deletion of chrom #7 long arm (include elastin gene); 特征性elfin faces, extremely friendly, cardiovascular problems hypercalceima (sensitive to VD)
ADA deficiency
adenosine deaminase deficiency: purine salvage pathway (AR) excessive ATP and dATP: feedback inhibit ribonucleotide reductase - prevent DNA synthesis - decrease lymphocyte count - SCID, 1st disease treated with gene therapy
Acyl-CoA Dehydrogenase
convert Acyl-CoA to Acetyl-CoA (for TCA or ketone formation) in beta-oxidation of FA deficiency: d. ketones and glucose, i. dicarboxylic acids (二羧酸)
Abetalipoproteinemia
AR, Hereditary defect in Microsomal Triglyceride Transfer Protein (MTP) causing inability to synthesize Lipoproteins due to deficiencies in ApoB-100 and ApoB-48 to pack stuff into VLDLs and inability to transport Chylomicrons out of cells First appears in first few months of life Presentation: Lipid Vitamin Deficiencies due to d. transport Failure to Thrive, Steatorrhea, Acanthocytosis(棘红细胞[增多]症) Ataxia, Night Blindness (VA), Fou Smelling Stools (dec lipid absorb) Hyporeflexia, d. Vibratory Sense (Vitamin E Deficiency) Diagnosis: Intestinal Biopsy shows Lipid Accumulation within Enterocytes due to inability to export absorbed lipid as Chylomicrons, VLDLs or LDLs d.Total Cholesterol d. Fat-Soluble Vitamins
snRNP function
remove introns from mRNAs SLE: Ab against U1-snRNP
PRPP
↑ ↓
5’-phosphoribosyl - 1’- pyrophosphate, key intermediate for de novo synthesis of purines and pyromidines. Increase in PRPP synthetase can cause uric acid (product of purine degradation), - gout
EDS
Ehlers–Danlos syndrome, AR or AD (6 types) defect in TypeI, III, V collagen: cross-linking hypermobile joints, skin hyperelasticity joint dislocation, berry aneurysms, organ rupture
ataxia telangiectasia
共济失调性毛细血管扩张症 ATM mutated DNA repair mechanism in ATM: can’t join the ends of 2 DNA fragments to repair ds-DNA breaks
Autosomal trisomies Downs
1:700, most commom cause of genetic retardation Drinking age: 21 孕检(abei): 低高低高(↓a-fetoprotein; ↑beta-hCG; ↓ estriol; ↑ inhibin A
Fomepizole
甲吡脞 Inhibit ADH(alcohol DH), an antidote for MeTH or ethylene glycol poisoning
carboxylase
transfer CO2 groups with the help of biotin (e.g., pyruvate carboxylase)
carnitine shuttle
FA metabolism: b-oxidation: Acyl-CoA transferred by carnitine from outer mito membrane (CAT I) to inner membrane (CAT II), and form acetyl-CoA - go into TCA, or form acetoacetate (1 of the 3 major ketone bodies) carnitine deficiency impairs ketone body formation, cause hypoketonic hypoglycemia
cavernous hemangioma
海绵状血管瘤
malate - aspartate cycle
苹果酸-天冬氨酸循环 generate 32 ATP/glucose (aerobic metabolism in heart and liver)
elastin-associated diseases
protein in skin, lung, arteries, vocal cords, ligamenta flava; rich in Gly and Pro, non-hydroxylated forms fibrillin scaffolding (Marfan’s syn, AD) broken down by elastase, which is inhibited by alpla1-antitrypsin (- emphysema,肺气肿)
Chediak-Higashi syn. (CHS) 契东综合症
AR; mutation in LYST gene (LYSosome Trafficking regulatory gene). the gene product is required for the microtubule-dependent sorting of endosomal proteins no polymerization > no intracellular movt of vesicles > no fusion of phagosome & lysosome > no phagolysosome form > granular defects leukocyte defects in chemotaxis, degranulation, killing signs: 1) pyogenic infection (化脓性感染)2)partial albinism; 3) peripheral neuropathy 先天性白细胞颗粒异常综合征, AR 家族有近亲婚配史为一种原因不明的全身性疾病。具有以下特点:①部分性皮眼白化病伴有眼球震颤与畏光;②常发生化脓性感染;③巨溶酶体颗粒 其白细胞内有大块异常颗粒,主要是一种巨大溶酶体,含有多种水解酶。这些异常颗粒主要结合在溶酶体酶上亦可结合在其他细胞上它们使吞噬细胞趋化性减弱杀菌功能缺陷,故患者容易感染
cell cycle: which protein is synthesized predominantly in S? Rb, p53 act on which phase? mutation result in
which protein is synthesized predominantly in S: histone (S = DNA synthesis) Rb, p53 act on which phase: G1 - S transition mutation result in Li-Fraumeni syn
cobalamin
钴胺素, Vit B12 co-factor for homocysteine methyltransferase and methylmalonyl-CoA mutase 缺乏引起:megaloblastic anemia, hypersegmented PMN(blood smear shows >6 segments in neutrophils, sign for缺VB12的巨细胞贫血), neurological syptoms包括paresthesias, abnormal myelin-subacute degeneration(as opposed to B9-叶酸 deficiency) very large pool stored in liver; deficiency caused by malabsorption(sprue口炎性腹泻,enteritis, lack intrnisic factors, lack terminal ileum (Crohn’s disease) 诊断:多步骤的Schilling test
collagen synthesis
6步: inside fibroblast: 1-4 steps 1). RER: synthesize preprocol: Gly-X-Y (X, Y = Pro, Lys) 2). ER: hydroxylation of Lys (need Vc - scurvy) 3). ER: glycosylation of hydroxyLys- pro-col, form triple helix of 3 pro-Col chains via hydrogen bonds and disulfide bonds - Osteogenesis imperfecta 4). exocytosis Step 5-6: outside of fibroblast: 5). proteolytic processing: remove disulfide bonds: pro- become tropocollagen, insoluable 6) cross-linking: covalent, by Cu+-containing lysyl oxidase) ; EDS
ETC
complex I: NADH dehydrogenase (NADH - NAD, electron transferred along the ETC) complex II: succinate dehydrogenase complex III: cyto b/c1 complex IV: cytochrome oxidase complex V: ATP synthase
Cori’s disease
type III GSD, AR debranching E (a-1,6-glucosidase) milder form of type I (von Gierke’s), fasting hypoglycemia, but blood lactate is normal (gluconeogenesis is intact)
cystic fibrosis (CF)
AR: Phe deletion in CFTR gene: mutation in the Cl- channal, most common lethal genetic disease in white population. thick mucus in lungs (recurrent pulmonary infection), chronic bronchitis, pancreatic insufficiency (malabsorption, steatorrhea脂溢性) 诊断:increase Cl- in sweat [note: if child with nasal polyps, which usually seen in adults: order a sweat test to R/O CF] 治疗:N-acetylcysteine to break up disulfide bonds in mucus glycoprotein, so loosen mucus plugs
cystine
胱氨酸(made of 2 cysteine connected by disulfade bond); cysteine: 半胱氨酸; homocysteine: 高胱氨酸
Wernicke’s encephalopathy –Korsakoff syndrome
缺VB1 WE三联征:confusion, opthalmoplegia (paralysis (-plegia) of one or more extraocular muscles which are responsible for eye movements导致double vision), ataxia Korsakoff syndrome: acute onset of severe memory impairment
Vitamines: water- or fat- solubale?
fat soluble:KEAD (fat kid = kead) 能在脂肪中聚集,因此毒性比水溶性的大 water soluble: B1, 2,3, 5, 6, 7, 9, 12, C
Edward syn 爱德华病-国王的演讲
T18: 智障,rocker-bottom feet,头小下巴小,small jaw, low-set ears(国王口吃,因为听不见);death within the 1st year; 2nd common live birth after Down’s 明显心血管(先心病)和头部发育畸形 婴儿特征的手部:Clenched hand and overlapping fingers: index finger overlaps third finger and fifth finger overlaps fourth finger, characteristically seen in Trisomy 18. 孕检(abei): 低低低常(↓a-fetoprotein; beta-hCG; ↓ estriol; 正常 inhibin A
eu vs prokaryote ribosomal units
eu: (Even) 40S + 60 S = 80 S prOka(Odd): 30S + 50 S = 70S tRNA A-ctivation (charging): use ATP translocation use: GTP (going places)
ethanol hypoglycemia机制
- increase NADH/NAD+ ratio in liver, cause pyruvate - lactate, OAA - malate - inhibit gluconeogenesis and TCA cycle 2. overproduce lactate - acidosis 3. depletion of OAA - shut down TCA, shunt acetyl-CoA to ketone production 4. break down excess malate increase NADPH - FAA synthesis 结果:低血糖,酸中毒,脂肪肝
Fabry’s disease: 无法不理手脚的麻木
XR; deficient E.: a-galacosidase A: accumulation of ceramide trihexoside; findings: peripheral neuropathy of hands/feet, angiokeramotas (血管角质瘤);cardiovascular/renal disease treatment: E. replacement (口服a-galactosidase A)
Vit E
antioxidant: protects erythocytes and membranes from free radical damage (E for erythrocytes); deficiency: hemolytic anemia; muscle weakness
folic acid
VB9, found in leafy green veggies, 储存在肝脏 converted to THF(tetrahydrofolate), important for the synthesis of nitrogenous bases in DNA/RNA(联想purine/pyramidine de novo syn;治疗:补thymine) US最常见的vitamine deficiency; seen in alcoholism and pregnancy 症状:megaloblastic anemia, no neurological syptoms (as opposed to B12 deficiency); cause neural tube defects in pregnancy 3 drugs to induced deficiency:phenytoin(抗癫痫), sulfonamides, MTX
Fragile x syndrome 脆弱的X染色体- 刘备(此人动不动就哭,脆弱综合征; 女里女气:x-chromosome problem)
Trinulceotide repeat expansion disease之一 X-Girlfriend: (CGG)n 刘备:大耳贼 巨大睾丸,长脸,大下巴,耳朵 智障 自闭。除downs 之外第二普遍的遗传智障(想想刘禅)
essential AA
AAs that need to be supplied from diet: 1) glucogenic: His, Met, Val (His met values) 2) ketogenic: Leu, Lys 3) glucogenic/ketogenic: He, Phe, Thr, Trp (HPTT)
free ribosome功能
synthesize cytosolic and organellar proteins
G6PDH deficiency
glucose-6-phosphate dehydrogenase deficiency: most common enzyme deficiency in human, X-linked recessive; more prevalent in Mediterraneans and blacks, increased resistance to malaria; through HMP shunt, G6PDH keeps the level of NAPDH (which keeps glutathione reduced to detoxify free radicals and peroxides). Decreased NADPH in RBCs leads to hemolytic anemia (excerabated by fava beans, infections) intrinsic defect, primarily intravascular hemolysis [can be induced by oxidative stress such as infection, and Fava beans] Heinz body: oxidized hemoglobin precipitated in RBC bite cells: splenic macrophages to remove Heinz bodies 诊断:active hemolysis screen with Heinz body prep
Gaucher’s disease (戈谢病)
AR; deficiency in glucocerebrosidase (=G; 葡萄糖脑苷脂酶) - accumulation of glucocerebroside (葡萄糖脑苷脂);most common LSD findings: hepatosplenogemaly (临床诊断中最常见的finding就是脾肿大, infiltrative diseases of macrophage in red pulp, lysosomal storage diease); necrosis of femur; 骨髓检查见有典型戈谢细胞 (Gaucher cell: macrophages that look like crumpled tissue paper); 中枢神经系统症状
cardiac glycosides机制
digoxin, digitoxin directly inhibit Na+- K+ ATPase - indirectly inhibit Na+/Ca2+ exchange - increase [Ca2+]i - increase cardiac contractility
RER
site for : 1) secretory proteins 2) N-linked oligosaccharide (added to many proteins) cells rich in RER: goblet cells in intestine (mucus), B-cells (Ab) 特殊的RER: Nissl body (in neurons), make E. and neurotransmiters, e.g. ChAT
Gibbs free energy change (⊿G0) positive means? negative means?
Gibbs free energy change (⊿G0) positive: favor the formation of the substrates negative means: favor the formation of products 不可能为零(= - RT InKeq)
metabolism sites
mito: FAA oxidation (beta-oxidation),oxidation phosphorylation; TCA cycle, acetyl-CoA production cytoplasm: glycolysis; synthesis of FAA, steriod (SER), protein (RER), cholesterol; HMP shunt both: HUGs take two (heme synthesis, urea cycle, gluconeogenesis)
xeroderma pigmentosum
着色性干皮病, dna修复酶缺乏病
Hartnup disease
autosomal recessive, defect neutral aa transporter on renal and intestinal epithelial cells; Trp (neural aromatic aa) excretion in urine and decrease absorption from the gut; cause pellagra (糙皮病: Trp是形成niacin的前体; 也can be caused by chronic lack of niacin (vitamin B3) in the diet. It can be caused by decreased intake of niacin or tryptophan, and possibly by excessive intake of leucine) signs: ataxia, erythmatous skin lesion (红斑), loose stool
Gower’s sign
Duchenne’s dystrophy特征,weakness of lower extremities
GSD: glycogen storage diseases
12 types: Very Poor Carbohydrate Metabolism, all AR type I: von Gierke’s type II: Pompe’s 庞培 type III: Cori’s type V: McArdle’s
hexokinase vs. glucokinase
hexokinse: expressed in all tissues expect liver and pancreas beta-cells; high affinity (low Km) and low capacity (low Vmax); uninduced by insulin; feedback inhibited by glucose-6-P glucokinase: in liver and pancreas beta-cell; low affinity (high Km), high capacity (high Vmax)。 it’s the glucose sensor in pancreatic beta-cells: mutation caused d. insulin - hyperglycemia
Vit K
coagulation factors II, VII, IX and X, and anticoagulatant proteins C and S conditions predisposing to VitK deficiency: 1) fat malabsorption (bile duct occlusion) 2) prolonged use of broad spectrum antibiotics (kill bacteria in intestine for VK supplement) 3) breast-fed newborns (breast milk has no VK) manifestation in adults: poor nutrition, occult blood in stool, prolonged PT (prothrombin time), normal liver function
VC
Vc 4大功能:1)C stands for “collagen” (Vc is a cofactor for Pro and Lys hydroxylases 羟化酶 in collagen synthesis) 2)antioxidant 3)facilitate iron absorption by keep iron in Fe2+ in the reduced form 4) necessary for dopamine hydroxylase to convert dopamine to NE
glycolysis 糖酵解
happens in cytoplasm; convert 1 glucose into 2 pyruvate and release moderate energy aerobic: pyruvate goes into TCA Cycle + acetyl-CoA - FA synthesis; in RBC and exersicing skeletal muscle: pyruvate changes to lactate (NADH - NAD)
HNPCC / Lynch syn
heretidary non-polyposis colon cancer 遗传性非息肉性结肠直肠癌 mutation in DNA mismatch repair (unlike sporadic colon cancer, which involve mutations of proto-oncogenes or anti-oncogenes) adenoma ⇒ carcinoma sequence: APC ⟹ K-ras, p53,
homocysteinuria
高胱氨酸尿症 i. homocysteine in urine, mental retardation, osteoporosis, kyphosis, lens subluxation; atherosclerosis (stroke, MI) 3 forms (all AR): cysteine becomes essential and needs from diet 1) d. CTS (cystathionine synthase, 胱硫醚合成酶)treat: d. Met, i. Cys, B12 and folic acid from diet 2) d. affinity of CTS for pyridoxal phosphate (treat: d. VB6 in diet) 3) HCMT deficiency (homocysteine methyl-transferase), require VB12
riboflavin
核黄素, Vit B2, FAD, FMN cofactor in oxidation and reductation (eg, FADH2) B2 = 2 ATP (FAD. FMN) The 2 Cs of B2: cheilosis (唇干裂), corneal vascularization