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Biochemistry

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Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. What is the amino acid precursor for histamine
Inc permeability of membrane causing a dec in proton gradient and inc in O2 consumption - ATP synthesis stops - but electron transport continues to produce heat
X linked frame shif mutation
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Histidine

2. What are the findings in orotic aciduria
Connective tissue
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
32 - malate aspartate shuttle

3. What test is used for B12 def
Basement membrane or basal lamina
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Cartilage - hyaline - vitreous body - nucleus pulposus
Schilling test

4. What does DNA poly I do?
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
MRNA - tRNA
Fed

5. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
B6
Glucose 6 phosphatase

6. What regulates whether FBPase -2 or PFK-2 is active
Protein kinase A
Epithelial cells
Inc CPK and muscle biopsy
Cartilage - hyaline - vitreous body - nucleus pulposus

7. What does a northern blot use as its sample
RNA
Facial flushing
Active secretion in lungs and GI - reabsorbs in skin
Proton gradient

8. Which direction does dynein go
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
Alpha and beta tubulin - dimers have two GTP bound
Post to neg
Lacks glucose 6 phophatase

9. What is the amino acid precuror for creatine - urea and nitric oxide
ATP and methionine
Arginine
Robertsonian translocation and mosaicism
Oxidized hemoglobin precipiated within RBCs

10. What converts DOPA to dopamine
Dopa decarboxylase
Zero
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor

11. What trinucleotide repeat in Huntingtons and what chromosome is it found on...
Von Gierke's - Pompe - Cori - McArdle
RER
CAG - 4
Rotenone - CN- - antimycin A - CO

12. What does the golgi add to serine and threonine residues
Grows slowly - collapses quickly
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Phosphofructokinase 1
O- oligosaccharaides

13. What apolipoprotein is on LDL
Carbomoyl phosphate synthetase I
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Microarrays
B100

14. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
B6
After citruline
Chylomicrons
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia

15. What does Citrate Is Krebs starting substrate for making oxaloacetate
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Krabbes - galactocerebrosidase - galactocerebroside - AR
Proline and lysine - vit C
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate

16. RNA poly can't proofread - but What can it do
Binds to LDL receptor - mediates VLDL secretion
Arg and his inc in histones Which bind negatively charged DNA
III - joint dislocation - anuerysms - organ rupture
Initiate chains

17. How do stable (quiescent) cells grow and regenerate and What are examples
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Neurons
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
GTP

18. What does the passage of electrons result in that when coupled to OXPHOS drives the production of ATP
Ca/calmodulin in muscle to coordinate with muscle activity
Proton gradient
Early in life - AR - inability to synthesize lipoproteins due to def in apoB100 and B48 - intestinal biopsy shows accumulation within enterocytes due to inability to export absorbed lipid as chylomicrons - failure to thrive - steatorrhea - acanthocyt
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase

19. What happens to glycogen in the liver
Zero
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
2 rings

20. What are the results of unbalanced translocation
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Skin
Accelearted muscle breakdown
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

21. For eukaryotes - Where does replication begin?
Consesus sequenec of base pairs
Schilling test
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

22. What is disulfiram used for
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Mediates extra remnant take up
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms

23. What order kinetics does EtOH dehydrogenase have
Dermatitis - enteritis - alopecia - adrenal insuff
Zero
RER
Inc melt - dec fluidity

24. What does primase do
Males are infertile due to bilateral absence of vas deferens
Makes RNA primer on which DNA poly III can initiate replication
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Free ribosomes

25. What is the breakdown product of dopamine
HVA
Alpha - ketoglutarate dehydrogenase complex
ATP and methionine
Phenytoin - MTX - and sulfonamides

26. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Von hippel lindau - 3
Inc insulin - dec cAMP - dec PKA
NADPH

27. What is the trinucleotide repeat in fragile X
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
1 ring
CGG

28. What is Gowers maneuver
Assistance of upper extremities to stand up
Inc NADH/NAD ratio in liver - causing diversion of pyruvate to lactate and OAA to malate - inhibiting gluconeogenesis and stimulating fatty acid synthesis. Leads to hypoglycemia and hepatic fatty liver change seen in chronic EtOH users
Alpha and beta tubulin - dimers have two GTP bound
Grows slowly - collapses quickly

29. hepatosplenomegaly - aseptic necrosis of femur - bone crisis - MACS that look like crumpled tissue paper

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30. What are the water soluble vitamins - which ones are stored
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year
Tuberous sclerosis
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR

31. What enzyme def can cause emphysema
ATP
5' of the incoming nucleotide
Phosphorylation - glycosylation - hydroxylation
Alpha1 antitrypsin

32. What is the complication of cystinuria
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
2pq
Facial flushing

33. characterize autosomal domint inheritance
P2 +2pq+ = 1
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Williams syndrome

34. What substances induce phosphofructokinase
Fibroblast
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Stop codon is recognized by release factor - and completed protein is released from ribosome
AMP - fructose 2 -6 BP

35. bilateral - massive enlargement of of kidneys due to multiple large cysts
Isocitrate dehydrogenase
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
ADPKD
Marfans

36. recurrent pulmonary infxns in CF are due to what organisms
Transmitted only through mother - all offspring of affected females may show signs of disease
Cri du chat
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Pseudomonas and s aureus

37. Pts with albinism are at inc risk For what cancer
Oxidizes substrate
Skin
Same AA - often base change in 3rd position of codon (tRNA wobble)
Von hippel lindau - 3

38. 1 g of protein or cabrohydrate = ?kcal
Four
DsRNA promotes degradation of target mRNA knocking down gene expression
FMR1 gene - methylation - associated with chromosomal breakage
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -

39. What causes patau's syndrome and What is it
Sucrose = glucose + fructose - lactose = glucose + galactose
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Neural tube
F16BP

40. What does hormone sensitive lipase do
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Von gierkes - glucose 6 phosphatase
Degradation of TG stored in adipocytes
Niacin - constituent of NAD and NADP - derived from tryptophan

41. What happens in carnitine def
F16BP
Antioxidant - facilitates iron absorption by keeping iron in the Fe2+ reduced state - necessary for hydroxylation of proline and lysine collagen bridges - necessary for dopamine beta hydroxylase which converts DA to NE
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

42. What does arsenic do and What are th results of poisoning
Accelearted muscle breakdown
Williams syndrome
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
TRNA

43. What causes Edwards syndrome and What is it
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year
Cri du chat
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet

44. In what cells do the respiratory burst occur
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Lactate
NADPH
PMNs

45. Which antifungal drugs work on microtubules
Cre - lox system
Griseofulvin
Krabbes - galactocerebrosidase - galactocerebroside - AR
SNP

46. Where is vit B12 found
Changed AA (convservative - new AA is similar in chemical structure)
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
One
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora

47. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
High output cardiac failure - dilated cardiomyopathy - edema
Familial hypercholesterolemia - hyperlipidemia type IIA
TTP
Deamination

48. What tissues have only aldose reductase
Schwann cells - lens - retina - kidneys
Cytosol
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year
Orotic acid to UMP

49. What is the function of Zinc
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Adds an inorganic phosphate onto substrate without using ATP
Binds 50S - blocking translocation
Lacks glucose 6 phophatase

50. What step begins the urea cycle and What is the enzyme needed - Where does it happen
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Dopa decarboxylase
Promotor - TATA box - and CAAT box - AT rich
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria