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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 are the water soluble vitamins - which ones are stored
Lariat shape in order and remove intron precisely and join 2 exons
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
Dec DNA - dec lymphos leads to SCID

2. What converts DOPA to dopamine
Von Gierke's - Pompe - Cori - McArdle
Promotor - TATA box - and CAAT box - AT rich
Lacks glucose 6 phophatase
Dopa decarboxylase

3. What causes maple syrup urine disease and What does it lead to...
Prokaryotic only - elongates leading strand by adding deoxnucTIDE to the 3' end. Elongates lagging strand until it reaches primer of preceeding fragment. 3' to 5' exonuclease activity 'proofreads' each added nucTIDE
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Dec in alpha ketoacid dehydrogenas leading to blocked degredation of branches amino acids like Ile - Leu - and Val - severe CNS defects mental retardation and death
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet

4. What is NAD+ generally used for
Reads usual codon but inserts wrong AA
Tryptophan
Skin
Catabolic processes to carry reducing equivalents away as NADH

5. What do DNA topoisomerases do
Microarrays
Fasting
Creat a nick in the helix to relieave supercoils created during replication
Unwinds DNA template at replcation fork

6. several distinct syndromes characterized by familial tumors of endocrine glands including pancreas - parathyroid - pituitary - thryoid and adrenal medulla - disorders and gene association
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
MEN - 2A and 2B with ret gene
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
HGPRT - defective purine salvage - excess uric acid production

7. Type IV BM
Prevent strands from reannealing
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
4 under the floor
Acetyl - CoA

8. How do labile celss grow and regenerate and What are examples
Acetyl - CoA to malonyl - CoA (2C to 3C)
1 ring
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia

9. What does a decrease in decrease in NADPH lead to and why
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Terminal regions - tropocollagen
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Same as sprint + OXPHOS

10. What are pyrimidines made from
Huntingtons
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Orotate precursor - with PRPP added later

11. What converts tyrosine to DOPA
Tryosine hydroxylase
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Particular sequence of DNA where replicatino begins - may be single of multiple
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding

12. What does lipoprotein lipase do
DNA
Degredation of TG circulating in chylomicrons and VLDLs
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
LCAT (lecithin cholesterol acyltransferase)

13. What enzyme def can cause emphysema
Ca/calmodulin in muscle to coordinate with muscle activity
Alpha1 antitrypsin
Ribos first then deoxyribos with ribonucleotide reductase
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

14. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
Only processed RNA
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
HMP shunt
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

15. How do fluoroquinolones work
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Eu - methionine - pro - formyl - methionine
NADH - NADPH - FADH2
Inhibit DNA gyrase specific for prokaryotic topoisomerase

16. How does patients present with ADPKD
B-100 - CII and E
Not all individuals with a mutant genotype show the mutant phenotype
Flank pain - hematuria - HTN - progressive renal failure
30 - glycerol -3- phosphate shuttle

17. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
Chylomicrons
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Each codon specifies only 1 amino acid
Cre - lox system

18. What enzyme converts phenylalanine to tyrosin
Eu - methionine - pro - formyl - methionine
Phenylalanine hydroxylase
B-100 - CII and E
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity

19. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Familial hypercholesterolemia - hyperlipidemia type IIA
Ketone - methyl

20. Why is albinism inheritnace varialbe due to...
No
SnRNPs
Alpha 1 -6 and alpha 1 -4
Locus heterogeneity - ocular albinism is x- linked recessive

21. A small proportion of Down syndrome is due to What two genetic events
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Post to neg
Degredation of dietary TG in small intestine
Robertsonian translocation and mosaicism

22. What clotting factors require vit K
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
II - VII - IX - X (1972) protein C and S
X- linked recessive
MRNA

23. What does Alports syndrome cause and why
Read from a fixed starting point as a continuous sequence of bases
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
75 to 90 - cloverleaf
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

24. What enzyme esterifies 2/3 of plasma cholesterol
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
G6PD
LCAT (lecithin cholesterol acyltransferase)

25. What is loss of heterozygosity and give an example
If pt inherits or develops a mutation in a tumor suppresor gene - the complementary allele must be deleted/mutated before cancer develops - not true of oncogenes - retinoblastoma
Infection - free radicals generated by inflammatory response
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

26. What does NADPH oxidase deficiency result in and why
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
B6
LDL
Oxidizes substrate

27. What are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
Cleft palate - cardiac abnl - pregs test
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Chylomicrons
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

28. What does CATCH 22 stand for and What causes is...
No
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
B100
Leu - lys

29. What is the source of energy in the fasting state between meals
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
Evident in first few days of life - can present last onest - excess carbamoyl phosphate converted to orotic acid - orotic acid in blood and urine - dec BUN and symptoms of hyerpammonemia
Hypoxanthine to xanthing and xanthine to uric acid

30. nucleotide repeat for fredreich's ataxia
Cartilage - hyaline - vitreous body - nucleus pulposus
GAA
Poly A polymerase - signal is AAUAA
Catabolic processes to carry reducing equivalents away as NADH

31. What substance inside the cells replenishes NADPH
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
G6PD
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
They yield only acetyl - CoA equivalents

32. bilateral - massive enlargement of of kidneys due to multiple large cysts
ADPKD
Oxidized hemoglobin precipiated within RBCs
Accelearted muscle breakdown
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns

33. What does the ELISA test for
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Result from phagocytic removal of heinz bodies my macs - G6PD def
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

34. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Terminal regions - tropocollagen
Alanine
SNP
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation

35. What does inc phenylalanine lead to...
Phenylketones in urine
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Four
More than 1 codon may code for the same amino acid

36. peripheral neuropathy - developmental delay - optic atrophy - glopoid cells
Biotin
Lacks glucose 6 phophatase
Stored ATP - creatine phosphate - anaerobic glycolysis
Krabbes - galactocerebrosidase - galactocerebroside - AR

37. How does cytosine become uracil
Deamination
Creat a nick in the helix to relieave supercoils created during replication
Superoxide dismutase
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

38. Type II cartilage
Arginine
Glycogenolysis to form glucose
Dermatitis - enteritis - alopecia - adrenal insuff
CarTWOlage

39. What does arsenic do and What are th results of poisoning
1 -25 OH2 D3 = calcitriol
High output cardiac failure - dilated cardiomyopathy - edema
ATP
Inhibits lipoic acid - vomiting - rice water stools - garlic breath

40. What is NADPH's role inside RBCs
Keep glutathione reduced so it can detoxify free radicals and peroxides
Lacks glucose 6 phophatase
Hepatic glycogenolysis - adipose tissue release of FFA - muslce and liver FFA - hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and proprionyl - coA (odd chain FFA)
Glycogen synthase

41. What is proteasomal degredation
Particular sequence of DNA where replicatino begins - may be single of multiple
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Attachment of ubiquitin to defective proteins tag them for breakdown

42. What is the RDE of glycogenolysis
Phenytoin - MTX - and sulfonamides
Glycogen phosphorylase
1 kind with multiple subunits
Inhibits lipoic acid - vomiting - rice water stools - garlic breath

43. What is the TX for CF and What does it do
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding
Myeloperoxidase

44. What is the breakdown product of epi
Metanephrine
Cre - lox system
Alkaptonuria - may have debiliating arthralgias
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs

45. What stretch of DNA that alters gene expression by binding of transcription factors
Phenytoin - MTX - and sulfonamides
Biotin
Enhancers
Alpha 1 -4 glucosidase

46. What causes Edwards syndrome and What is it
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
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
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Inc CPK and muscle biopsy

47. What is the treatment for dec affinity of cystathionine synthase for pyroxidal phosphate
Inc vit B6
Acetyl - CoA to malonyl - CoA (2C to 3C)
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Collagen

48. What reaction does adenosine deaminase normally catalyze
Inc CPK and muscle biopsy
Adenosine to inosine
Tyrosine
Carnitine acyltransferase I

49. Where is vit A found in the diet
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Liver and leafy veggies
Inc melt - dec fluidity
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue

50. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
Activates LCAT
Von hippel lindau - 3
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Inc insulin - dec cAMP - dec PKA