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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. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Myeloperoxidase
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
CGG
Liver - also in kidney and gut epithelium

2. In what cell is collagen synthesis initiated
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
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Fibroblast

3. How is ammonium transported from muscle to the liver for urea cycle
Degradation of TG stored in adipocytes
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
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
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)

4. What does a northern blot use as its sample
Oral uridine administration
Degredation of TG circulating in chylomicrons and VLDLs
RNA
Dec DNA - dec lymphos leads to SCID

5. What does NADPH oxidase deficiency result in and why
Reads usual codon but inserts wrong AA
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
CG- 3 > AT-2 - More CG content - melting point goes up

6. hepatosplenomegaly - aseptic necrosis of femur - bone crisis - MACS that look like crumpled tissue paper

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7. What is the RDE of de novo pyrimidine synthesis
Carbomoyl phosphate synthetase II
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Neuralgia
Adds 2 carbon with the help of biotin

8. What tissue samples are used for karyotyping
Creat a nick in the helix to relieave supercoils created during replication
CGG
Blood - bone marrown - amniotic fluid - placental tissue
ATP - citrate

9. decreases In what substances can cause PKU
Unmethylated - newly synthesized - HNPCC
Tropoelastin with fibrillin scafolding
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
HDL

10. What does DNA poly I do?
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Flank pain - hematuria - HTN - progressive renal failure
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two

11. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Alanine
Dec methionine - inc cystiene - inc B12/folate
Cri du chat

12. Type II cartilage
CarTWOlage
Inhibits 50S peptidyltransferase
Arg - lys - his - arg is most basic - has has no charge at body pH
No - its non homologous

13. What causes Hartnup's disease
5' to 3'
Mitochondria
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Lysine and leucine

14. What does an umabiguous genetic code refer to...
Each codon specifies only 1 amino acid
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle
X- linked recessive

15. What is the result of vit B5 def
Unwinds DNA template at replcation fork
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
RNA
Inc intestinal absorption fo calcium and phosphate - inc bone resorption

16. What are the findings in orotic aciduria
No
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Huntingtons
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

17. What causes biotin def
Carnitine acyltransferase I
Antibiotic use or excessive ingestion of raw eggs
PFK - rate limiting enzyme
ATP

18. What lab technique is use to profile gene expression levels of thousands of genes simultaneously to study certain diseases and treatments
Alpha 1 -4 glucosidase
9+2 arrangement of microtubules
Microarrays
Phosphofructokinase 1

19. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
HGPRT - defective purine salvage - excess uric acid production
Defect in fibrillin
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

20. What is the Hardy Weinberg disease prevalence equation
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
NAD+
P2 +2pq+ = 1
Mitochondria

21. NADPH are used In what 4 things
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Mcardle's - skeletal muscle glycogen posphorylase
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Carnitine acyltransferase I

22. Type I collagen
Liver and leafy veggies
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
SnRNPs and other proteins
Bone - skin - tendon - dentin - fascia - cornea - late wound repair

23. In which direction is protein synthesized
Inc Cl - in sweat
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
N to C
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

24. What inhibits the carnitine shuttle
Liver hepatocytes and steroid producing cells of the adrenal cortex
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
Malonyl coa
Bind 30s subunit preventing attachment of aminoacyl - tRNA

25. Which amino acids are elastin rich in
1 -25 OH2 D3 = calcitriol
Fasting
Proline and glycine (non glycosylated forms)
SnRNPs

26. What is the defect in cystinuria
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Procollagen - triple helix of 3 alpha collagen chains
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Glycine

27. energy malnutrition resulting in tissues and muscle wasting - loss of subQ fat - variable edema
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Vit K antagonist
Marasmus - muscle wasting
Tryosine hydroxylase

28. What is the rate determining enzyme (RDE) of glycolysis
Four
Phosphofructokinase 1
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies

29. What happens in folate def
Neg to pos
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

30. What does a phosphorylase do
Adds an inorganic phosphate onto substrate without using ATP
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Night blindness - dry skin

31. What is the composition of urea and where do each part derive from
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
40 - 60 - 80
Mucus secreting globlet cells and antibody secreting plasma cells
Wernicke - korsakoff - dry and wet beriberi

32. What are the only purely ketogenic amino acids
Lysine and leucine
Methionine encode by only 1 codon (AUG)
Nissl body - enzyme and NTs
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty

33. What does osteogenesis imperfecta causes and why
SnRNPs
Promotor - TATA box - and CAAT box - AT rich
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
Histidine

34. What is the initial transcript called and What is the capped and tailed transcript called
Tryptophan
SAM
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Polyneuritis - symmetrical muscle wasting

35. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Alanine
Conversion of NE to epi
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
CAG

36. What happens on the oxidative arm of the HMP shunt and What is the key enzyme
Dermatitis - alopecia - enteritis
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
APRT + PRPP
Cyclin dependent kinases;constitutive and inactive

37. What is mosaicism and give an example
Locus heterogeneity - ocular albinism is x- linked recessive
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
Robertsonian translocation and mosaicism
Debranching enzyme

38. What causes Edwards syndrome and What is it
Trisomy 18 - severe mental retardation - rocker bottom feet - micrognathia - low set ears - clenched hands - prominent occiput - congenital heart disease - death usually within the first year
By inhibiting formation of the initiation complex and cause misreading of mRNA
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Mutated dystrophin gene - less severe - adolescence

39. What part of the pre mRNA contains the actual genetic information coding for protein
Semiconservative - continuous and discontinuous strands (okazaki fragments)
LCAT (lecithin cholesterol acyltransferase)
Exons
DTMP

40. nucleotide repeat for fredreich's ataxia
Poly A polymerase - signal is AAUAA
GAA
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Marasmus - muscle wasting

41. Which kind of osteogenesis imperfecta is fata in utero or in neonatal period
Oxidative is irreversible
Inc dicarboxylic acids - dec in glucose and ketones
Type II
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins

42. What is a silent mutation
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
3' end (with CCA)
Same AA - often base change in 3rd position of codon (tRNA wobble)

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

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44. Which RNA poly opens DNA at promotor site
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Dermatitis - glossitis - and diarrhea
RNA poly II
Flank pain - hematuria - HTN - progressive renal failure

45. What does cytokeratin stain for
X linked frame shif mutation
HMG- CoA (HMG- CoA to mevalonate
Cri du chat
Epithelial cells

46. What are the glucogenic essential amino acids
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Neurofibromatosis type 1 (von Recklinghausens disease)
Met - val - arg his
Disorder of aromatic amino acid metabolism

47. What collagen type is most frequently affected in ehlers danlos and What are common complications
Phosphofructokinase 1
Lysine and leucine
III - joint dislocation - anuerysms - organ rupture
Comlex II

48. What happens with dry beriberi
Glycogen and FFA oxidation; glucose conserved for final sprinting
RNA poly II
Polyneuritis - symmetrical muscle wasting
Carbomoyl phosphate synthetase II

49. What is the activated carrier for electrons
NADH - NADPH - FADH2
1 -25 OH2 D3 = calcitriol
Post to neg
Prevent strands from reannealing

50. What does the golgi do to sugars in proteoglycans and of selected tyrosine on proteins
Q -
Sulfation
Must be both activated and inactivated for cell cycle to progress
ATP and methionine