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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 RDE of fatty acid synthesis
CAG - 4
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Nonsense > missense > silent
Acetyl - CoA carboxylase (ACC)

2. What occurs to oxaloacetate in starvation and DKA
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Site of steroid synthesis and detoxification of drugs and poisons
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies

3. What does DNA poly I do?
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Y shaped region along the DNA template where leading nad lagging strands are synthesized

4. What are the water soluble vitamins - which ones are stored
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
75 to 90 - cloverleaf
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)

5. What is the RDE of fatty acid oxidation
Carnitine acyltransferase I
BOne
Targets the proteins for lysosome
Oxidizes substrate

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

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7. What are covalent alterations
Polyneuritis - symmetrical muscle wasting
Debranching enzyme
Phosphorylation - glycosylation - hydroxylation
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol

8. What causes Marfan syndrome
2pq
AMP - fructose 2 -6 BP
Defect in fibrillin
Sulfation

9. What is the amino acid precursor for catecholamines
Phosphorylation - glycosylation - hydroxylation
Phenylalanine
Inc insulin - dec cAMP - dec PKA
Colchicine

10. What is the order of severity for the different types of mutations
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Nonsense > missense > silent
Same AA - often base change in 3rd position of codon (tRNA wobble)
BOne

11. Of the four possible fates for pyruvate - which one can replenish TCA cycle or be used in gluconeogenesis
Oxalacetate
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Bruton's agammaglobulinemia - wiskott - aldrich - fabrys disease - G6PD def - ocular albinism - Lesch - Nyhan syndrome - Duchenne and Becker Muscular Dystrophy - hunter's syndrome - hemophilia A and B
Active secretion in lungs and GI - reabsorbs in skin

12. What does cytokeratin stain for
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Fibrofatty replacement of muscle - cardiac myopathy
RNA
Epithelial cells

13. What is the activated carrier for methyl groups
SAM
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
APC on chromosome 5
Poly A polymerase - signal is AAUAA

14. peripheral neuropathy of hands/feet - angiokeratomas - CV/renal disease - dz - def enzyme - acc substrate - inherit
APKD1 on chromosome 16
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Zero

15. What is the RDE of ketogenesis
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
ATP and methionine
HMG- CoA synthase

16. What are the 4 assumption of the Hardy Weinberg law
MRNA
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
5' to 3'
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

17. How do tetracyclines work
TRNA
Liver - ovaries - seminal vesicles
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA

18. Severe fasting hypoglycemia - inc glycogen storage in liver - inc blood lactate - hepatomegaly - dz and def enzyme
Avidin
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Von gierkes - glucose 6 phosphatase
Fed

19. trinucleotide repeat fo myotonic dystrophy
CarTWOlage
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
CTG

20. A small proportion of Down syndrome is due to What two genetic events
Robertsonian translocation and mosaicism
Chylomicrons
RRNA
Arg and his inc in histones Which bind negatively charged DNA

21. What is the amino acid precursor for porphyrin and heme
Catabolic processes to carry reducing equivalents away as NADH
Facial flushing
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
Glycine

22. several distinct syndromes characterized by familial tumors of endocrine glands including pancreas - parathyroid - pituitary - thryoid and adrenal medulla - disorders and gene association
Dermatitis - alopecia - enteritis
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
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
MEN - 2A and 2B with ret gene

23. What substances induce phosphofructokinase
AMP - fructose 2 -6 BP
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Binds 50S - blocking translocation
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate

24. What is the results of vit B1 def
4 under the floor
Facial flushing
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)

25. What enzyme converts adenine to AMP
LDL
APRT + PRPP
Isocitrate dehydrogenase
Liver hepatocytes and steroid producing cells of the adrenal cortex

26. What causes maple syrup urine disease and What does it lead to...
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
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
OTC has hyperammonemia - orotic aciduira does not
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

27. How do cardia glycosides work
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
25OHD3
Adds an inorganic phosphate onto substrate without using ATP
Cytosol - F 1 -6 BP to fructose 6 Phosphate

28. What causes patau's syndrome and What is it
DNA
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
CG- 3 > AT-2 - More CG content - melting point goes up
NAD+

29. What is the energy source after day 3 of starvation
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
CGG
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Met - val - arg his

30. What does glycosylation of pro alpha chian yield and What is the structure
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
Procollagen - triple helix of 3 alpha collagen chains
Asp and Glu
Carbomoyl phosphate synthetase II

31. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
Lariat shape in order and remove intron precisely and join 2 exons
Cri du chat
Tryosine hydroxylase
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)

32. What converts DOPA to dopamine
Dopa decarboxylase
Same as sprint + OXPHOS
Lariat shape in order and remove intron precisely and join 2 exons
After citruline

33. Do balanced translocations cause abnl phenotype
No
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
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

34. What is the Name and fxn of vit B5
Phenylalanine hydroxylase
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
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
B12 and folate

35. Where is vit A found in the diet
Liver and leafy veggies
Marasmus - muscle wasting
Free ribosomes
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

36. Why can't even chain fatty acids produce new glucose
5' to 3'
Arg and his inc in histones Which bind negatively charged DNA
17 - 17 letters in von Recklinghausen
They yield only acetyl - CoA equivalents

37. Type III collagen
LCAT (lecithin cholesterol acyltransferase)
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Tuberous sclerosis
Lariat shape in order and remove intron precisely and join 2 exons

38. What does degenerate/rundant genetic code refer to...
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
Conversion of NE to epi
More than 1 codon may code for the same amino acid
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia

39. What is the target of the 3' hydroxyl attack
The triphosphate bond
Protein
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Two

40. What regulates whether FBPase -2 or PFK-2 is active
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
LDL
Protein kinase A
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis

41. What does hepatic TG lipase do
N to C
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Degradation of TG remaining in IDL

42. What does apoB100 do
25OHD3
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
Glycine - aspartate - glutamine
Binds to LDL receptor - mediates VLDL secretion

43. What is the defect in cystinuria
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Essential fructosuria - fructokinase AR
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects

44. What is maternal PKU
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Neimann - pick - sphingomyelinase - sphingomyelin - AR

45. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Liver - also in kidney and gut epithelium
LDL
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Malabsorption and steatorrhea (ADEK)

46. ADPKD is associated with What additional conditions
Lactate
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Protein kinase A
CAG - 4

47. What is incomplete penetrence and give an example
Read from a fixed starting point as a continuous sequence of bases
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Not all individuals with a mutant genotype show the mutant phenotype

48. I g fat = ? Kcal
Conversion of NE to epi
FISH
Nine
Purines= A - G pyrimidine = C - T (U)

49. How is vit D stored
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Peroxide
25OHD3
One

50. What fxn does glucokinase serve in the liver
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
PCR - denaturation - annealing - elongation
III - joint dislocation - anuerysms - organ rupture
FAP