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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 are the findings in Down's syndrome
Liver hepatocytes and steroid producing cells of the adrenal cortex
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Mental retardation - flat facies - prominent epicanthal folds - simian crease - gap between 1st 2 toes - duodenal atresia - congenital heart disease (ASD) - inc risk of All and Alzheimers

2. What tissue samples are used for karyotyping
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Degradation of TG stored in adipocytes
Blood - bone marrown - amniotic fluid - placental tissue
O- oligosaccharaides

3. What converts dopamine to NE
Silencers
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Dopamine beta hydroxylase

4. What substance inside the cell reduces glutatione
Ribose 5- P to PRPP
ATP
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
NADPH

5. FAP is due to deletion On what gene On what chromosome
APC on chromosome 5
Enhancers
Lysine and arginine
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects

6. What are the mRNA stop codons
Muscle
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Kwashiorkor - small child with swollen belly
UGA - UAA and UAG

7. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Acetyl - CoA
Liver - also in kidney and gut epithelium
Flagella - cilia - mitotic spindles
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

8. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Intermediate filaments
Comlex II
Dermatitis - alopecia - enteritis

9. What is the limiting reagent in EtOH metabolism
NAD+
Thymic - parathyroid and cardiac
Pyruvate to oxaloacetate (3C to 4C)
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1

10. What does amino acid catabolsim results in the formation of what?
Essential fructosuria - fructokinase AR
Heterochromatin = HighlyCondensed
Phosphofructokinase 1
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted

11. Very Poor Carbohydrate Metabolism stands for 4 of the glycogen storage diseases - What are thy

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12. What is the order of severity for the different types of mutations
32 - malate aspartate shuttle
Karyotyping
Nonsense > missense > silent
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase

13. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Cartilage - hyaline - vitreous body - nucleus pulposus
HGPRT - defective purine salvage - excess uric acid production
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
CGG

14. How do macrolides and clindamycin work
Binds 50S - blocking translocation
Disease
Asp and Glu
Assistance of upper extremities to stand up

15. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Alanine
Liver hepatocytes and steroid producing cells of the adrenal cortex
Inhibits the Na/K pump by binding the K side
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

16. bilateral acoustic schwannomas - juvenile cataracts
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side
Abnormal protein folding - degradation before reaching cell surface
NF2 on chromosome 22
TRNA

17. What is the treatment for cystathionine synthase def
Dec methionine - inc cystiene - inc B12/folate
Lacks glucose 6 phophatase
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes

18. What is the active form of vit D
1 -25 OH2 D3 = calcitriol
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Fibroblast
EtOH dehydrogenase and acetaldehyde dehydrogenase

19. How do tetracyclines work
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Phenylalanine hydroxylase
Mutated dystrophin gene - less severe - adolescence
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA

20. Delivers hepatic cholesterol to peripheral tissues - formed by LPL modification of VLDL in the peripheral tissue - taken up by target cells via RME
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Lactate
LDL

21. What is the treatment for orotic aciduria
The triphosphate bond
Oral uridine administration
Must be both activated and inactivated for cell cycle to progress
Glycogenolysis to form glucose

22. What is the result of vit B5 def
CG- 3 > AT-2 - More CG content - melting point goes up
Dermatitis - enteritis - alopecia - adrenal insuff
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
HMG- CoA reductase

23. What happens to oxaloacetate in alcholism
Supply sufficient glucose to brain and RBCs and to preserve protein
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies

24. What enzyme converts adenine to AMP
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
PFK - rate limiting enzyme
APRT + PRPP
Palate - facial and cardiac defects

25. What does inc phenylalanine lead to...
Phenylketones in urine
Isocitrate dehydrogenase
Particular sequence of DNA where replicatino begins - may be single of multiple
ATP and methionine

26. How does chloramphenicol work
Inhibits 50S peptidyltransferase
Leu - lys
Phenylketones in urine
Antibiotic use or excessive ingestion of raw eggs

27. What causes B12 def
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Microtubules
ATP and methionine

28. cytoskeletal elements associated with cilia - flagella - mitotic spindle - neurones and centrioles
Unmethylated - newly synthesized - HNPCC
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Inhibits the Na/K pump by binding the K side
Microtubules

29. antbiotic controlled promoter to induciblly manipulate genes at specific developmental points
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
Foliage - small reserve in liver - eat green leaves
2 -4 DNP - aspirin
Cre - lox system

30. What are pyrimidines made from
Orotate precursor - with PRPP added later
Acetyl - CoA
After citruline
Must be both activated and inactivated for cell cycle to progress

31. If two alleles are present - but the active allele is deleted - what happens
Disease
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Leu - lys
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

32. What does lipoprotein lipase do
Alpha and beta tubulin - dimers have two GTP bound
Degredation of TG circulating in chylomicrons and VLDLs
Zero
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first

33. What does SAM do
X- linked recessive
Transfers methyl units
Wernicke - korsakoff - dry and wet beriberi
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)

34. bilateral - massive enlargement of of kidneys due to multiple large cysts
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
ADPKD
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
25OHD3

35. Pts with albinism are at inc risk For what cancer
Skin
Attachment of ubiquitin to defective proteins tag them for breakdown
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Arg and his inc in histones Which bind negatively charged DNA

36. What does the golgi do to sugars in proteoglycans and of selected tyrosine on proteins
Sulfation
Oxalacetate
High output cardiac failure - dilated cardiomyopathy - edema
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP

37. How does abetalipoproteinemia present and What is the defect
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
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
CAG
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step

38. What does the golgi apparatus do on asparagine
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Modifies N- oligosaccharides
Protective against malaria
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

39. What is the hardy weinber heterozygote prevalence
ADPKD
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
2pq
Alcohol version of glucose - can trap glucose in cell - aldose reductase

40. 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
Connective tissue
Neither of 2 alleles is dominant - blood groups
VLDL

41. What is the pathway in the fasting state leading to inc FBPase -2 and dec PFK-2
Inc glucagon - inc cAMP - inc PKA
Von hippel lindau - 3
ATP and alanine
Brittle bone disease - most commonly lead AD with abnl type I collagen causing multiple fractures with minimal trauma - blue sclerae due to translucency of connective tissue over the choroid - hearing loss - dental imperfections due to lack of dentin

42. What does apoA 1 do
Inc Cl - in sweat
Ribos first then deoxyribos with ribonucleotide reductase
APKD1 on chromosome 16
Activates LCAT

43. What 3 steps in RNA processing occur after transcription

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44. The pyruvate dehydrogenase complex serves In what reaction: products
Acetly- CoA - CO2 - NADH
APKD1 on chromosome 16
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Mcardle's - skeletal muscle glycogen posphorylase

45. What are the products for glycolysis
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Cytosol - F 1 -6 BP to fructose 6 Phosphate
ADPKD
Schwann cells - lens - retina - kidneys

46. What is the result of vit B5 def
Inc dicarboxylic acids - dec in glucose and ketones
HMG- CoA synthase
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

47. What is Gowers maneuver
Vincritsine/vinblastine
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)
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Assistance of upper extremities to stand up

48. What test is used for B12 def
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Degredation of dietary TG in small intestine
Schilling test
VMA

49. What is the breakdown product of dopamine
HVA
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Ca/calmodulin in muscle to coordinate with muscle activity
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination

50. inc glycogen in muscle but can't break it down - painful muscle cramps - myglobinuria with strenuous exercise - dz and enzyme

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