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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 does biotin def cause
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Wrinkles and acne
Protein
Dermatitis - alopecia - enteritis

2. What substances induce phosphofructokinase
APC on chromosome 5
Met - val - arg his
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
AMP - fructose 2 -6 BP

3. Why does alpha amanitin cause liver failure and Where is it found
Palate - facial and cardiac defects
Inhibits RNA polymerase II - found in death cap mushrooms
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA

4. What is the hardy weinberg allele prevalence
Inhibits 50S peptidyltransferase
P+q = 1
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility

5. A small proportion of Down syndrome is due to What two genetic events
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Von Gierke's - Pompe - Cori - McArdle
Robertsonian translocation and mosaicism

6. What happens to glycogen in the liver
Tryptophan
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Inhibit DNA gyrase specific for prokaryotic topoisomerase

7. What is maternal PKU
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

8. What is used to diagnose muscular dystrophies
Inc CPK and muscle biopsy
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
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
B100

9. Describe the replication fork
Y shaped region along the DNA template where leading nad lagging strands are synthesized
RNA poly II
MEN - 2A and 2B with ret gene
Arginine

10. caf
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Neurofibromatosis type 1 (von Recklinghausens disease)
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Inhibits RNA polymerase II - found in death cap mushrooms

11. What chromosome is the NF gene on...
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
17 - 17 letters in von Recklinghausen
MRNA - tRNA
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -

12. What step begins the urea cycle and What is the enzyme needed - Where does it happen
Active secretion in lungs and GI - reabsorbs in skin
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
The triphosphate bond
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

13. What are bite cells and when do you see them
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Result from phagocytic removal of heinz bodies my macs - G6PD def
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Deamination

14. Which amino acids are elastin rich in
Familial hypercholesterolemia - hyperlipidemia type IIA
Proline and glycine (non glycosylated forms)
LCAT (lecithin cholesterol acyltransferase)
Consesus sequenec of base pairs

15. What are the two transgenic strategies in mice
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Free ribosomes
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
HMG- CoA synthase

16. What initiates protein synthesis
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Changed AA (convservative - new AA is similar in chemical structure)
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive

17. What is the breakdown product of dopamine
HVA
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
ATP hyrdolysis couple to energetically unfavorable rxns
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

18. Which kind of osteogenesis imperfecta is fata in utero or in neonatal period
Same as sprint + OXPHOS
Type II
Krabbes - galactocerebrosidase - galactocerebroside - AR
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein

19. progressive neurodegeneration - hepatosplenomegaly - cherry red spot on macula - foam cells
Mitochondria
Acetyl - CoA carboxylase (ACC)
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Neimann - pick - sphingomyelinase - sphingomyelin - AR

20. benign asymptomatic condition with elevated levels of fructose in urine and blood - dz and enzyme
HMG- CoA reductase
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Essential fructosuria - fructokinase AR
Liver - also in kidney and gut epithelium

21. What are the results of unbalanced translocation
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Von gierkes - glucose 6 phosphatase
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Chronic granulomatous disease - no respiatory burst - no formatino of ROS

22. bilateral acoustic schwannomas - juvenile cataracts
NF2 on chromosome 22
B6
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
Attachment of ubiquitin to defective proteins tag them for breakdown

23. cytoskeletal elements in micorvilli - muscle contracting fibers - cytokenesis - adherens jxns
LCAT (lecithin cholesterol acyltransferase)
Actin and myosin
Arg and his inc in histones Which bind negatively charged DNA
Unwinds DNA template at replcation fork

24. Which direction does kinesin go
NF2 on chromosome 22
Neg to pos
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
They yield only acetyl - CoA equivalents

25. What happens with dry beriberi
Polyneuritis - symmetrical muscle wasting
5' to 3'
1 ring
N to C

26. RNA poly can't proofread - but What can it do
Initiate chains
Base + ribose + phosphate (3' -5') phosphodiester bond
Targets the proteins for lysosome
NADPH

27. How do fluoroquinolones work
Inc CPK and muscle biopsy
Reads usual codon but inserts wrong AA
No - its non homologous
Inhibit DNA gyrase specific for prokaryotic topoisomerase

28. What shuttle is involved in fatty acid synthesis and What does it move From where to where
Mucus secreting globlet cells and antibody secreting plasma cells
Citrate - acetyl coa from mito to cyto
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Cofactor for LPL

29. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Inc glucagon - inc cAMP - inc PKA
Supply sufficient glucose to brain and RBCs and to preserve protein
HGPRT - defective purine salvage - excess uric acid production

30. What are pyrimidines made from
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Binds 50S - blocking translocation
Occurs when cells in the body have different genetic makeup - can be germline mosaic - which may produce a disease that is not carried by parents somatic cells - lyonization - random X inactivation in females
Orotate precursor - with PRPP added later

31. What happens with wet beriberi
Seals.
High output cardiac failure - dilated cardiomyopathy - edema
CG- 3 > AT-2 - More CG content - melting point goes up
Type II

32. What are cyclins
PCR - denaturation - annealing - elongation
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

33. What neuroanatomical strutures are injured in wernicke - korsakoff
Malonyl coa
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
G6PD
Medial dorsal nucleus of thalamus - mamillary bodies

34. What does vit E def cause
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
VMA
Particular sequence of DNA where replicatino begins - may be single of multiple
Polycystic liver disease - berry aneurysm - mitral valve prolapse

35. What does aminoacyl tRNA synthetase do the AA before and after it binds to tRNA - and what happens if it's the wrong the match
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Glucose -6 phosphate
Scrutinizes - hydrolyzes the bond
Adipse tissue stores - keton bodies become the main source of energy fo the brain and heart - after these are depleted - vital protein degradation accelerates - leading to organ failure and death

36. What do neurofilaments stain for
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
TTP
Neurons
Fibroblast

37. Gene imprinting implies that How many alleles are active at a single locus
One
Marasmus - muscle wasting
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity

38. What is the prevalence of an X- linked recessive disease in males and in females
3' end (with CCA)
Must be both activated and inactivated for cell cycle to progress
Cytosol
Q -

39. What inhibits pyruvate kinase
ATP and alanine
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Nissl body - enzyme and NTs
Schwann cells - lens - retina - kidneys

40. What metabolic rxns occur in both the cytoplasm and mitochondria
Post to neg
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Protein kinase A
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two

41. What reaction does adenosine deaminase normally catalyze
Nonsense > missense > silent
Chylomicrons
Night blindness - dry skin
Adenosine to inosine

42. characterize x linked dominant
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Glycine
L form
Phenylalanine

43. What happens in folate def
Blood - bone marrown - amniotic fluid - placental tissue
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
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

44. What is the main source of folate
Binds 50S - blocking translocation
Foliage - small reserve in liver - eat green leaves
Phenylketones in urine
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

45. what findings are associated with marfans
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Biotin
II - VII - IX - X (1972) protein C and S
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease

46. What is locus heterogeneity and give an example
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Diphyllobothrium latum

47. What other inflammatory process can induce a hemolytic anemia in NADPH defieicnt patients
Infection - free radicals generated by inflammatory response
Kidney - ears - eyes
EtOH dehydrogenase and acetaldehyde dehydrogenase
Carbomoyl phosphate synthetase I

48. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Cytosol
Transfers methyl units
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns

49. What tissues have both enzymes of sorbitol metabolism
32 - malate aspartate shuttle
Makes RNA primer on which DNA poly III can initiate replication
Liver - ovaries - seminal vesicles
Anabolic processes as a supply of reducing equivalents

50. What is the order of severity for the different types of mutations
Nonsense > missense > silent
After day 1
FMR1 gene - methylation - associated with chromosomal breakage
FISH