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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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1. What is loss of heterozygosity and give an example
Fasting
1 -25 OH2 D3 = calcitriol
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
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

2. What is the most common urea cycle disorder and What is the mode of inheritance?
HMG- CoA (HMG- CoA to mevalonate
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Glycogenolysis to form glucose
Achondroplasia

3. peripheral neuropathy of hands/feet - angiokeratomas - CV/renal disease - dz - def enzyme - acc substrate - inherit
Autosomal recessive diseases
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
HMG- CoA (HMG- CoA to mevalonate
Consesus sequenec of base pairs

4. What enzyme turns ROS to H2O2
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Superoxide dismutase
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Essential fructosuria - fructokinase AR

5. What does apoB100 do
Proline and lysine - vit C
Mucus secreting globlet cells and antibody secreting plasma cells
Binds to LDL receptor - mediates VLDL secretion
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

6. What do the single stranded binding proteins do
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Catabolic processes to carry reducing equivalents away as NADH
Prevent strands from reannealing

7. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Intermediate filaments
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Phenylalanine
SNP

8. What apolipoprotiens are on VLDL
B-100 - CII and E
GAA
Abnormal protein folding - degradation before reaching cell surface
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

9. What are cyclins
Catabolic processes to carry reducing equivalents away as NADH
Base + ribose
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Purines= A - G pyrimidine = C - T (U)

10. Which step in the de novo purine and pyrimidine synthesis pathway requires aspartate - glycine - glutamine and THF
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
Ribose 5- P to PRPP
Elastase - inhibited by alpha1 antitrypsin
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR

11. What is pleiotropy and given an example
MEN - 2A and 2B with ret gene
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Polyneuritis - symmetrical muscle wasting
Activates LCAT

12. What is the prevalence of an X- linked recessive disease in males and in females
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Unwinds DNA template at replcation fork
Q -
Consesus sequenec of base pairs

13. What does vit C def cause
Scrutinizes - hydrolyzes the bond
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

14. Infection with what organism can cause B12 def
HGPRT - defective purine salvage - excess uric acid production
THFs
Diphyllobothrium latum
Mutated dystrophin gene - less severe - adolescence

15. caf
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
75 to 90 - cloverleaf
Fibrofatty replacement of muscle - cardiac myopathy
Neurofibromatosis type 1 (von Recklinghausens disease)

16. What are the reactants for glycolysis
They yield only acetyl - CoA equivalents
Glucose - 2Pi - 2ADP - 2NAD+
Active secretion in lungs and GI - reabsorbs in skin
Creat a nick in the helix to relieave supercoils created during replication

17. What is chediak higashi
PFK - rate limiting enzyme
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
25OHD3
SAM

18. What is the breakdown product of epi
Inc melt - dec fluidity
Arg and his inc in histones Which bind negatively charged DNA
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy
Metanephrine

19. What reaction does adenosine deaminase normally catalyze
Adenosine to inosine
THFs
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

20. nucleotide repeat for fragile x
Epithelial cells
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
17 - 17 letters in von Recklinghausen
CGG

21. What is the trinucleotide repeat in fragile X
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
CGG
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Prevent strands from reannealing

22. protein malnutrition resulting in skin lesions - edema and liver malfxn
Kwashiorkor - small child with swollen belly
Peroxide
PFK - rate limiting enzyme
Bone - skin - tendon - dentin - fascia - cornea - late wound repair

23. What is the order of severity for the different types of mutations
Carnitine shuttle - acyl - coa from cyto to mito
Nonsense > missense > silent
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
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

24. characterize autosomal recessive inheritance
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
OTC has hyperammonemia - orotic aciduira does not
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1

25. What is the result of vit B5 def
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
HMG- CoA reductase
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Particular sequence of DNA where replicatino begins - may be single of multiple

26. How is ATP used by the cell
II - VII - IX - X (1972) protein C and S
ATP hyrdolysis couple to energetically unfavorable rxns
Cleft palate - cardiac abnl - pregs test
Malonyl coa

27. What is the energy source for tRNA actication (charging)
Nature and severity of phenotype vary from 1 individual to another - NF type 1
ATP
Marasmus - muscle wasting
Silencers

28. What two cells are particularly rich in RER
IDL
NADPH
In ER - glucose 6- P to glucose
Mucus secreting globlet cells and antibody secreting plasma cells

29. spheroid RBCs due to spectrin or ankyrin defect - hemolytic anemia - inc MHCH - splenectomy is curative
Hereditary spherocytosis
Vincritsine/vinblastine
Degradation of TG remaining in IDL
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year

30. How is Lesch Neyhan inherited
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
X- linked recessive
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Robertsonian translocation and mosaicism

31. What is the most abundant type of RNA
RRNA
Exercise: inc NAD/NADH - inc ADP - inc Ca
Dermatitis - glossitis - and diarrhea
F16BP

32. How do fluoroquinolones work
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Inhibit DNA gyrase specific for prokaryotic topoisomerase
Comlex II
Glucose -6 phosphate

33. What is the RDE of the urea cycle
4 under the floor
Pyruvate - NAD+ - CoA
Carbomoyl phosphate synthetase I
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase

34. delivers hepatic TGs to peripheral tissue - secreted by liver
1 kind with multiple subunits
VLDL
Cartilage - hyaline - vitreous body - nucleus pulposus
SNP

35. NADPH are used In what 4 things
Glutamate
Dec DNA - dec lymphos leads to SCID
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Antibiotic use or excessive ingestion of raw eggs

36. Type III collagen
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Hyperlipidemia
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
RRNA

37. What ribosomes do eukaryotes have
40 - 60 - 80
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase
NAD+
HMG- CoA reductase

38. What enzyme does fructose metabolism bypass to reach glycolysis
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding
Phenylalanine
Mebendazole/thiabendazole
PFK - rate limiting enzyme

39. What residues are hydroxylated in step 2 of collagen synthesis - and What does this require
Euchromatin
Proline and lysine - vit C
Glutamine PRPP amidotransferase
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US

40. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Kwashiorkor - small child with swollen belly
TTP

41. Type IV collagen
Basement membrane or basal lamina
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Acetyl - CoA
Removal of N or C termal propeptides from zymogens to generate mature proteins

42. How do you diagnose CFTR
LCAT (lecithin cholesterol acyltransferase)
EtOH dehydrogenase and acetaldehyde dehydrogenase
Inc Cl - in sweat
Wrinkles and acne

43. In what direction are DNA and RNA synthesized

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44. What happens to oxaloacetate in alcholism
Procollagen - triple helix of 3 alpha collagen chains
GTP
Lariat shape in order and remove intron precisely and join 2 exons
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

45. What are ketone bodies made from - where are they metabolized and how are they excreted
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Exercise: inc NAD/NADH - inc ADP - inc Ca
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine

46. Type II collagen
Base + ribose + phosphate (3' -5') phosphodiester bond
Degradation of TG remaining in IDL
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
Cartilage - hyaline - vitreous body - nucleus pulposus

47. How many rings do purines have
After day 1
2 rings
2 -4 DNP - aspirin
Exercise: inc NAD/NADH - inc ADP - inc Ca

48. In eukaryotes - What does RNA poly I make
Unmethylated - newly synthesized - HNPCC
RRNA
Males are infertile due to bilateral absence of vas deferens
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

49. Milder form of type I with nl blood lactate levels - dz and enzyme

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50. 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
Dermatitis - enteritis - alopecia - adrenal insuff
Read from a fixed starting point as a continuous sequence of bases
Avidin