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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 apoB100 do
RRNA
Binds to LDL receptor - mediates VLDL secretion
32 - malate aspartate shuttle
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles

2. What enzyme catalyzes the rxn from pyrvuate to Acetyl - CoA and what inhibits it
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Type II
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

3. What is used to diagnose muscular dystrophies
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
32 - malate aspartate shuttle
Inc CPK and muscle biopsy
Nissl body - enzyme and NTs

4. What is the smallest mutation a mircoarray can detect
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
SNP
LCAT (lecithin cholesterol acyltransferase)
SAM

5. How does cytosine become uracil
Deamination
Tryosine hydroxylase
Promotor - TATA box - and CAAT box - AT rich
HMP shunt

6. What does commaless - nonoverlapping genetic code refer to...
Cofactor for LPL
Read from a fixed starting point as a continuous sequence of bases
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Protein

7. What does Adenosine deaminase deficiency cause a build up of - and What does that lead to?
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
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
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Free ribosomes

8. What does cytokeratin stain for
Epithelial cells
African Americans and Asians
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Proton gradient

9. What occurs to oxaloacetate in starvation and DKA
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Neuralgia
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
F16BP

10. What substance in egg whites binds biotin
B6
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Avidin
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)

11. What enzyme adds Cl - to the H202 to makes bleach
Myeloperoxidase
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Phosphorylation - glycosylation - hydroxylation

12. How is orotic aciduria inherited
AR
Alanine
Vit K antagonist
OTC has hyperammonemia - orotic aciduira does not

13. What CETP do
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
P2 +2pq+ = 1
Avidin
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)

14. What does universal genetic code refer to and What are some exception
Mucus secreting globlet cells and antibody secreting plasma cells
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Neurons

15. In base excision repaire - what recognizes and removes damaged bases and what cuts the DNA to remove the empty sugar
Specific glycosylases - AP endonuclease
Glycogenolysis to form glucose
Asp and Glu
Cre - lox system

16. In eukaryotes - What does RNA poly II make
MRNA
Inc CPK and muscle biopsy
Histidine
Fructose 1 -6 bisphosphate

17. In which structures do you find microtubules
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Anabolic processes as a supply of reducing equivalents
Flagella - cilia - mitotic spindles

18. What does the ELISA test for
Uses ATP to add high energy phophate group onto substrate
Purines= A - G pyrimidine = C - T (U)
Abnormal protein folding - degradation before reaching cell surface
Antigen - antibody reactivity - can look for antigen or antibody in patients blood

19. What two cells are particularly rich in RER
Mucus secreting globlet cells and antibody secreting plasma cells
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Breaks down acyl - coa to acetyl coa groups in mito

20. What is the structure of elastin
Passed to glutamate - then to alanine enters blood - enters liver - coverted to pyruvate and transfers ammonium back to glutamate which gives it to the urea cycle
Superoxide dismutase
Tropoelastin with fibrillin scafolding
Inc intestinal absorption fo calcium and phosphate - inc bone resorption

21. What does glycosylation of pro alpha chian yield and What is the structure
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Hyperlipidemia
P+q = 1
Procollagen - triple helix of 3 alpha collagen chains

22. protein malnutrition resulting in skin lesions - edema and liver malfxn
Cri du chat
Kwashiorkor - small child with swollen belly
Changed AA (convservative - new AA is similar in chemical structure)
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT

23. What 3 amino acids are necessary for purine synthesis
Glycine - aspartate - glutamine
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Inhibits the Na/K pump by binding the K side
The triphosphate bond

24. What is the mutation in beckers muscular dystrophy - What is the severity and time of onset
Mutated dystrophin gene - less severe - adolescence
Protein kinase A
3' end (with CCA)
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

25. When are glycogen reserves depleted
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
After day 1
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
P2 +2pq+ = 1

26. Why enzyme breaks down elastin and what enzyme inhibits it
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Elastase - inhibited by alpha1 antitrypsin
Inhibit DNA gyrase specific for prokaryotic topoisomerase
Changed AA (convservative - new AA is similar in chemical structure)

27. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Achondroplasia
Neg to pos
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine

28. What is anticipation and give an example
Neither of 2 alleles is dominant - blood groups
Proline and glycine (non glycosylated forms)
Ketone - methyl
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

29. What is the RDE of de novo purine synthesis
Facial flushing
Fibroblast
Schwann cells - lens - retina - kidneys
Glutamine PRPP amidotransferase

30. What causes B12 def
Malapsorption syndromes like sprue or CF or mineral oil intake
Changed AA (convservative - new AA is similar in chemical structure)
FMR1 gene - methylation - associated with chromosomal breakage
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns

31. What is loss of heterozygosity and give an example
Hereditary spherocytosis
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Acetyl - CoA
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

32. What does inc phenylalanine lead to...
Neither of 2 alleles is dominant - blood groups
Phenylketones in urine
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
THFs

33. Giving folate during early pregnancy is important to prevent what birth defects
Four
Tryptophan
Neural tube
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20

34. What enzyme degrades a small amount of glycogen in lysosomes
Alpha 1 -4 glucosidase
ATP - citrate
Poly A polymerase - signal is AAUAA
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS

35. What are the symptoms of vit A excess
Anabolic processes as a supply of reducing equivalents
Exercise: inc NAD/NADH - inc ADP - inc Ca
Niacin - constituent of NAD and NADP - derived from tryptophan
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia

36. What is the trinucleotide repeat in fragile X
Ile - phe - thr - trp
CGG
Krabbes - galactocerebrosidase - galactocerebroside - AR
Alpha1 antitrypsin

37. The golgi apparatus fxns as a distribution center between what organelles in the cell and What does it process
Silencers
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Robertsonian translocation and mosaicism
Arg - lys - his - arg is most basic - has has no charge at body pH

38. What are the glucogenic essential amino acids
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Degredation of dietary TG in small intestine
Met - val - arg his

39. What are the findings in PKU
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Skin

40. What is imprinting and give an example

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41. How do you diagnose CFTR
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Inc Cl - in sweat
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Cytosol

42. What happens in vit K def
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
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

43. What is NADPH's role inside RBCs
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Glycogen synthase
Keep glutathione reduced so it can detoxify free radicals and peroxides
Mediates chylomicron secretion

44. What causes Marfan syndrome
1 kind with multiple subunits
Defect in fibrillin
Semiconservative - continuous and discontinuous strands (okazaki fragments)
After citruline

45. What kind of branches do glycogen branches have
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Kwashiorkor - small child with swollen belly
Uses ATP to add high energy phophate group onto substrate
Alpha 1 -6 and alpha 1 -4

46. Which carbon bears the triphosphate and the energy source for bond formation

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47. Which end of the tRNA is the amino acid bound to...

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48. What is the longest time of RNA and shortest
Diphyllobothrium latum
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
MRNA - tRNA
Liver - ovaries - seminal vesicles

49. What is the TX for pyruvate dehydrogenase deficiency
Conversion of NE to epi
Blood - bone marrown - amniotic fluid - placental tissue
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Hypoxanthine to xanthing and xanthine to uric acid

50. What does DNA poly III do?

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