Test your basic knowledge |

Biochemistry

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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 made fir rNucleotides or deoxyrNucleotides and what enzyme is necessary to convert one to the next
Tyrosine
Stop codon is recognized by release factor - and completed protein is released from ribosome
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
Ribos first then deoxyribos with ribonucleotide reductase

2. Where is vit B12 found
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
Males are infertile due to bilateral absence of vas deferens
Binds 50S - blocking translocation

3. In eukaryotes - What does RNA poly I make
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
RRNA
Acetoacetate and beta hydroxybutyrate
THFs

4. Fluorescent DNA or RNA probe binds to specific gene of interest - used for specific localization of genes and direct visualization of anomalies - like microdeletions - at molecular level
1 -25 OH2 D3 = calcitriol
Abnormal protein folding - degradation before reaching cell surface
FISH
Antioxidant - protects RBCs and membrances from free radical damage

5. What converts DOPA to dopamine
Prokaryotic only - elongates leading strand by adding deoxnucTIDE to the 3' end. Elongates lagging strand until it reaches primer of preceeding fragment. 3' to 5' exonuclease activity 'proofreads' each added nucTIDE
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Arg and his inc in histones Which bind negatively charged DNA
Dopa decarboxylase

6. What inhibits pyruvate kinase
Locus heterogeneity - ocular albinism is x- linked recessive
Tuberous sclerosis
SNP
ATP and alanine

7. What are the findings in orotic aciduria
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Alpha - ketoglutarate dehydrogenase complex
Degredation of TG circulating in chylomicrons and VLDLs
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

8. What is the fxn of vit K
Assistance of upper extremities to stand up
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora

9. What substances induce phosphofructokinase
AMP - fructose 2 -6 BP
Accelearted muscle breakdown
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Rb and p53

10. What two proteins make up microtubules and how are they arranged
Alpha and beta tubulin - dimers have two GTP bound
Robertsonian translocation and mosaicism
Phenylalanine
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS

11. What is the amino acid precursor for porphyrin and heme
Promotor - TATA box - and CAAT box - AT rich
Glycine
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Phenylketones in urine

12. When does aspartate enter the urea cycle
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Anchor muscle fibers - primarily in skeletal and cardiac muscle
After citruline
Neg to pos

13. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
NF2 on chromosome 22
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Liver - also in kidney and gut epithelium
Binds to LDL receptor - mediates VLDL secretion

14. What is the results of vit B1 def
CAG
Tuberous sclerosis
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

15. What reaction does adenosine deaminase normally catalyze
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Protein kinase A
Protein
Adenosine to inosine

16. What test is used for B12 def
Fibrofatty replacement of muscle - cardiac myopathy
Schilling test
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
APC on chromosome 5

17. What is the defectin IV - hypertriglyceridemia
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Histidine
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Rotenone - CN- - antimycin A - CO

18. What is the function and name of vit B6
Lacks glucose 6 phophatase
Carnitine shuttle - acyl - coa from cyto to mito
Bind 30s subunit preventing attachment of aminoacyl - tRNA
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

19. Where is hexokinase found - What is its Km and Vmax and what uninduces it
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
DsRNA promotes degradation of target mRNA knocking down gene expression
Bind 30s subunit preventing attachment of aminoacyl - tRNA

20. What is the target of the 3' hydroxyl attack
Dermatitis - alopecia - enteritis
17 - 17 letters in von Recklinghausen
LDL
The triphosphate bond

21. What is the defect in II A familial hypercholesterolemia
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Essential fructosuria - fructokinase AR
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

22. What is heteroplasmy
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
Dermatitis - enteritis - alopecia - adrenal insuff

23. What is the amino acid precursor for GABA and glutathione
Two
Glutamate
Hypoglycemia
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

24. What does desmin stain for
Glutamine PRPP amidotransferase
Muscle
Schwann cells - lens - retina - kidneys
Dec DNA - dec lymphos leads to SCID

25. What is the fxn of vit D
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
PMNs
Alpha 1 -4 glucosidase
9+2 arrangement of microtubules

26. What ribosomes do eukaryotes have
Silencers
32 - malate aspartate shuttle
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
40 - 60 - 80

27. In addition to fructose and galactose - what sugards should be excluded from the diets of patients with disorders of fructose or galactose metabolism
Sucrose = glucose + fructose - lactose = glucose + galactose
Nine
Robertsonian translocation and mosaicism
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies

28. How does abetalipoproteinemia present and What is the defect
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
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
Cyclin dependent kinases;constitutive and inactive

29. What happens to glycogen in the liver
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
CGG
PFK - rate limiting enzyme
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage

30. What is the RER called in neurons and What is made there
Neurons
Ketone - methyl
Nissl body - enzyme and NTs
Sulfation

31. Pts with albinism are at inc risk For what cancer
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
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
Skin
More than 1 codon may code for the same amino acid

32. What are purines made from
Colchicine
IMP precursor
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
Inc Cl - in sweat

33. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
Inc vit B6
Stored ATP - creatine phosphate - anaerobic glycolysis
Poly A polymerase - signal is AAUAA
Fibrofatty replacement of muscle - cardiac myopathy

34. What is RNAi used for
Polyneuritis - symmetrical muscle wasting
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
Mucus secreting globlet cells and antibody secreting plasma cells
DsRNA promotes degradation of target mRNA knocking down gene expression

35. What is imprinting and give an example

36. What does a kinase do
Enhancers
Fructose 1 -6 bisphosphate
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Uses ATP to add high energy phophate group onto substrate

37. What is the hardy weinberg allele prevalence
Actin and myosin
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
P+q = 1
Rotenone - CN- - antimycin A - CO

38. What shuttle is used in fatty acid degredation and What does it move and From where to where
Carnitine shuttle - acyl - coa from cyto to mito
Reads usual codon but inserts wrong AA
APC on chromosome 5
Phenylethamolamine N methyl transferase

39. 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
Degredation of TG circulating in chylomicrons and VLDLs
MEN - 2A and 2B with ret gene
Free ribosomes

40. Why is G6PD def more common among patients of african decent
Wrinkles and acne
Wobble
Palate - facial and cardiac defects
Protective against malaria

41. Describe robertsonian translocation
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Metanephrine
1 -25 OH2 D3 = calcitriol
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue

42. Synthesis of vit B3 requires what other vitamin
Kidney - ears - eyes
No - its non homologous
Flank pain - hematuria - HTN - progressive renal failure
B6

43. How do stable (quiescent) cells grow and regenerate and What are examples
Inhibit DNA gyrase specific for prokaryotic topoisomerase
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Acetly- CoA - CO2 - NADH
Orotic acid to UMP

44. What is the energy source for translocation
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
GTP

45. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
Promotor - TATA box - and CAAT box - AT rich
X linked frame shif mutation

46. pyruvate carboxylase catalyzes what rxn
Read from a fixed starting point as a continuous sequence of bases
Basement membrane or basal lamina
Uses ATP to add high energy phophate group onto substrate
Pyruvate to oxaloacetate (3C to 4C)

47. What happens in zinc def
Transmitted only through mother - all offspring of affected females may show signs of disease
Metanephrine
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
Dopa decarboxylase

48. What kind of branches do glycogen branches have
African Americans and Asians
Alpha 1 -6 and alpha 1 -4
Microarrays
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse

49. What are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Cleft palate - cardiac abnl - pregs test

50. What enzyme results in classic galactosemia and What is the clinical
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact