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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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1. What causes maple syrup urine disease and What does it lead to...
After citruline
Same as sprint + OXPHOS
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
Inhibits the Na/K pump by binding the K side

2. For eukaryotes - Where does replication begin?
Consesus sequenec of base pairs
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
ATP hyrdolysis couple to energetically unfavorable rxns
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1

3. Why enzyme breaks down elastin and what enzyme inhibits it
Phosphofructokinase 1
O- oligosaccharaides
Elastase - inhibited by alpha1 antitrypsin
CFTR gene - 7 - Phe 508

4. What substances induce phosphofructokinase
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Degredation of dietary TG in small intestine
Schwann cells - lens - retina - kidneys
AMP - fructose 2 -6 BP

5. Of the four possible fates for pyruvate - which one is a transition from glycolysis to TCA cycle
X linked frame shif mutation
NF2 on chromosome 22
Acetyl - CoA
Miscarriage - stillbirth - chromosomal imbalance (down - patau)

6. What happens in the first stage of collagen synthesis - and Where does it happen
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Citrate - acetyl coa from mito to cyto
Avidin

7. What is disulfiram used for
Exons
Lysine and leucine
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
HMG- CoA synthase

8. Formed and degradation of VLDL - delivers TGs and cholesterol to liver where they are degraded to LDL
IDL
Phenylethamolamine N methyl transferase
CG- 3 > AT-2 - More CG content - melting point goes up
Lariat shape in order and remove intron precisely and join 2 exons

9. What can excess vit B3 cause
Facial flushing
Mediates extra remnant take up
Acetyl - CoA
Phosphorylation - glycosylation - hydroxylation

10. What enzyme degrades a small amount of glycogen in lysosomes
Alpha 1 -4 glucosidase
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
GAA
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates

11. Which anti breast cancer drugs work on micortubules
Paclitaxel
Griseofulvin
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs

12. What are the blood glucose levels maintained by for days 1-3
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)
Collagen
Griseofulvin
CFTR gene - 7 - Phe 508

13. characterize mitochondrial inheritance
Lysine and leucine
Not all individuals with a mutant genotype show the mutant phenotype
Mutated dystrophin gene - less severe - adolescence
Transmitted only through mother - all offspring of affected females may show signs of disease

14. Inhibition of thymidilate synthase and and DHFR lead to decrease In what substance
Kidney - ears - eyes
DTMP
No - its non homologous
Robertsonian translocation and mosaicism

15. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
CFTR gene - 7 - Phe 508
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Bone - skin - tendon - dentin - fascia - cornea - late wound repair

16. what disease can cause pellagra
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Alpha 1 -4 glucosidase
Active secretion in lungs and GI - reabsorbs in skin

17. What does a defective Cl channel do
Ile - phe - thr - trp
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Citrate - acetyl coa from mito to cyto
De novo pyrimidine synthesis and urea - ornithine transcarbamoyl def in the urea cycle leads to a build of CP - then converted to orotic acid in pyrimidine synthesis pathway

18. Which cells are rich in smooth ER
Liver hepatocytes and steroid producing cells of the adrenal cortex
Night blindness - dry skin
Same as sprint + OXPHOS
Phosphorylation - glycosylation - hydroxylation

19. What does an umabiguous genetic code refer to...
Lysine and arginine
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Each codon specifies only 1 amino acid
Degradation of TG stored in adipocytes

20. What is the activated carrier for aldehyddes
No
HMG- CoA synthase
TTP
Lactate

21. What substances are uncouling agents
F16BP
2 -4 DNP - aspirin
Site of steroid synthesis and detoxification of drugs and poisons
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects

22. What test is used for B12 def
Oxidative and nonoxidative - no ATP produced or used
Schilling test
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Citrate - acetyl coa from mito to cyto

23. What does the ELISA test for
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Oligomycin
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Seals.

24. What are the function of vit C
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Free ribosomes
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

25. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
Met - val - arg his
BOne
Familial hypercholesterolemia - hyperlipidemia type IIA
Targets the proteins for lysosome

26. Milder form of type I with nl blood lactate levels - dz and enzyme
Removes phosphate group from substrate
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
Polyneuritis - symmetrical muscle wasting
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

27. What are the irreversible enzymes of gluconeogenesis
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
9+2 arrangement of microtubules
Exercise: inc NAD/NADH - inc ADP - inc Ca
Removal of N or C termal propeptides from zymogens to generate mature proteins

28. What is the amino acid precursor for catecholamines
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
DsRNA promotes degradation of target mRNA knocking down gene expression
Hereditary spherocytosis
Phenylalanine

29. What does Alports syndrome cause and why
RNA poly II
Nissl body - enzyme and NTs
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Stop codon is recognized by release factor - and completed protein is released from ribosome

30. What is the physiologic role of dystrophin
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Oral uridine administration
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin

31. What is the defect in cystinuria
Glucose -6 phosphate
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Pyroxidine - converted to pyroxidine phosphate a cofactor used in transamination - decarboxylation - glycogen phosphorylase - cystathionine synthesis and heme synthesis - required for synthesis of niacin and tryptophan

32. In which state is FBPase -2 active
Fasting
Reads usual codon but inserts wrong AA
1 ring
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted

33. What is the order of severity for the different types of mutations
Nonsense > missense > silent
De novo pyrimidine synthesis and urea - ornithine transcarbamoyl def in the urea cycle leads to a build of CP - then converted to orotic acid in pyrimidine synthesis pathway
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted

34. What does cytokeratin stain for
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Degredation of dietary TG in small intestine
Epithelial cells

35. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
Antibiotic use or excessive ingestion of raw eggs
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Chylomicrons
Phosphorylation - glycosylation - hydroxylation

36. What is the amino acid precursor for porphyrin and heme
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Glycine
Microarrays
Dec DNA - dec lymphos leads to SCID

37. What are the characteristics of prader willi syndrome How does it occur
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
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
Wrinkles and acne
Neg to pos

38. Which enzyme involved in RNA synthesis does not require a template
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Poly A polymerase - signal is AAUAA
Zero
PFK - rate limiting enzyme

39. What is heteroplasmy
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Wernicke - korsakoff - dry and wet beriberi
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Wobble

40. What is the RDE of the HMP shunt
RRNA
Glucose 6 phosphate dehydrogenase (G6PD)
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Mcardle's - skeletal muscle glycogen posphorylase

41. How do macrolides and clindamycin work
NADH - NADPH - FADH2
Unwinds DNA template at replcation fork
P+q = 1
Binds 50S - blocking translocation

42. What causes Marfan syndrome
Intermediate filaments
Cytosol
Defect in fibrillin
SnRNPs

43. What is the breakdown product of epi
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Metanephrine
Dermatitis - enteritis - alopecia - adrenal insuff
Nature and severity of phenotype vary from 1 individual to another - NF type 1

44. What drugs can cause folate def
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Phenytoin - MTX - and sulfonamides
Mutated dystrophin gene - less severe - adolescence
1 kind with multiple subunits

45. What happens in vit K def
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Blood - bone marrown - amniotic fluid - placental tissue
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

46. What is the initial transcript called and What is the capped and tailed transcript called
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Mucus secreting globlet cells and antibody secreting plasma cells

47. What enzyme def can cause emphysema
Alpha1 antitrypsin
Conversion of NE to epi
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Modifies N- oligosaccharides

48. What does high cholesterol or long saturated fatty acid content do to the melting temperature and fluidity
UGA - UAA and UAG
Inc melt - dec fluidity
1/4 of offspring from 2 carrier parents are affected - often enzyme def - usually only seen in 1 generation - often more sever than AD - presents in childhood
3' end (with CCA)

49. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
Phenylketones in urine
FAP
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

50. What does beta oxidation do and Where does it occur
Breaks down acyl - coa to acetyl coa groups in mito
Oligomycin
Epithelial cells
Diphyllobothrium latum

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