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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 the primary transcript combine with to form the spliceosome
Lysine and arginine
SnRNPs and other proteins
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible

2. Who typically has lactase def
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
African Americans and Asians
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

3. How does ethanol induce hypoglycemia
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
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus

4. What is the function of folic acid
Ile - phe - thr - trp
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Dec methionine - inc cystiene - inc B12/folate
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA

5. bilateral acoustic schwannomas - juvenile cataracts
NF2 on chromosome 22
B6
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR

6. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
P+q = 1
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Von hippel lindau - 3
1 -25 OH2 D3 = calcitriol

7. What enzyme catalyzes the rxn from pyrvuate to Acetyl - CoA and what inhibits it
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Aminoacyl - tRNA binds A site - ribosomal rRNA catalyzes peptide bond formation - transfers growing peptide to AA in A site - ribosome advances 3 nucTIDE toward 3' end of RNA - moving peptidyl RNA to P side
Hereditary spherocytosis
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora

8. What inhibits the carnitine shuttle
25OHD3
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Creat a nick in the helix to relieave supercoils created during replication
Malonyl coa

9. What are the two transgenic strategies in mice
Sever atherosclerotic disease early in life - and tendon xanthomas on the achilles - MI may develop before 20
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Enhancers
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene

10. What is the order of severity for the different types of mutations
Metanephrine
5' of the incoming nucleotide
30 - glycerol -3- phosphate shuttle
Nonsense > missense > silent

11. What does vit E def cause
Paclitaxel
Comlex II
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Procollagen - triple helix of 3 alpha collagen chains

12. What metabolic rxns occur in both the cytoplasm and mitochondria
CAG - 4
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
PMNs
Disorder of aromatic amino acid metabolism

13. What are the 3 AR forms of homocystinuria
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def

14. What is the fxn of vit D
MEN - 2A and 2B with ret gene
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Degredation of dietary TG in small intestine
Inc intestinal absorption fo calcium and phosphate - inc bone resorption

15. What is NADPH used for
Zero
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Exercise: inc NAD/NADH - inc ADP - inc Ca
Anabolic processes as a supply of reducing equivalents

16. In prokaryotes - What does makes the different types of RNA
1 kind with multiple subunits
Intermediate filaments
Citrate - acetyl coa from mito to cyto
Flagella - cilia - mitotic spindles

17. What happens on the oxidative arm of the HMP shunt and What is the key enzyme
They yield only acetyl - CoA equivalents
Epithelial cells
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Rotenone - CN- - antimycin A - CO

18. recurrent pulmonary infxns in CF are due to what organisms
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Marfans
Pseudomonas and s aureus
Binds 50S - blocking translocation

19. What are cyclins
Alanine
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
75 to 90 - cloverleaf
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

20. What is the activated carrier for methyl groups
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Cytosol
Liver hepatocytes and steroid producing cells of the adrenal cortex
SAM

21. What happens at the smooth ER
Liver hepatocytes and steroid producing cells of the adrenal cortex
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
Site of steroid synthesis and detoxification of drugs and poisons
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive

22. What is the breakdown product of epi
SnRNPs and other proteins
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Metanephrine

23. fibrillin defect leading to connective tissue disorder affecting skeleton - heart - and eyes
Tropoelastin with fibrillin scafolding
Marfans
Neurons
Fructose 1 -6 bisphosphate

24. Why enzyme breaks down elastin and what enzyme inhibits it
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Result from phagocytic removal of heinz bodies my macs - G6PD def
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Elastase - inhibited by alpha1 antitrypsin

25. What does a northern blot use as its sample
HDL
RNA
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL

26. What ribosomes do eukaryotes have
40 - 60 - 80
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Mutated dystrophin gene - less severe - adolescence

27. What does lactase deficiency cause
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Core proteins

28. Which type of chromatin is condensed - transcriptionally inactive - sterically inaccessible?
Heterochromatin = HighlyCondensed
Rb and p53
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Protein kinase A

29. What is the energy source in the fed state right after a meal
Anabolic processes as a supply of reducing equivalents
NADH - NADPH - FADH2
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Glycolysis and aerobic respiration

30. This is the site where negative regulators bind
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Orotic acid to UMP
Silencers
Fed

31. Which bond is stronger AT or CG and why? What is the laboratory consequence of this?
Inc CPK and muscle biopsy
CG- 3 > AT-2 - More CG content - melting point goes up
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Antioxidant - protects RBCs and membrances from free radical damage

32. 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
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
FISH
Targets the proteins for lysosome
Carnitine acyltransferase I

33. What occurs to oxaloacetate in starvation and DKA
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Autosomal recessive diseases
Oligomycin
Type II

34. What order kinetics does EtOH dehydrogenase have
Zero
Inc insulin - dec cAMP - dec PKA
Terminal regions - tropocollagen
Oxidative is irreversible

35. What is the source of energy in the fasting state between meals
Inc insulin - dec cAMP - dec PKA
Glycogen phosphorylase
LCAT (lecithin cholesterol acyltransferase)
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA

36. What is the treatment for orotic aciduria
Malapsorption syndromes like sprue or CF or mineral oil intake
GTP
Oral uridine administration
Connective tissue

37. What defects characterize DiGeorge syndrome
Ca/calmodulin in muscle to coordinate with muscle activity
Thymic - parathyroid and cardiac
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Alcohol version of glucose - can trap glucose in cell - aldose reductase

38. What metabolic rxns occur in the cytoplasm
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
Stored ATP - creatine phosphate - anaerobic glycolysis
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Males are infertile due to bilateral absence of vas deferens

39. What can vit B3 be used to treat
X linked frame shif mutation
Microtubules
Hyperlipidemia
Secretion of abnl thick mucus that plugs lungs - pancreas - liver

40. What does a pyruvate dehydrogenase deficiency lead to and What are the findings
Binds 50S - blocking translocation
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Alpha 1 -4 glucosidase
Attachment of ubiquitin to defective proteins tag them for breakdown

41. What does the golgi add to serine and threonine residues
Fibroblast
Removes phosphate group from substrate
Vit K antagonist
O- oligosaccharaides

42. What does DNA ligase do
Seals.
Stop codon is recognized by release factor - and completed protein is released from ribosome
Exons
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

43. Of the four possible fates for pyruvate - which one carries amino groups to liver from muscle
Alanine
ATP
Stored ATP - creatine phosphate - anaerobic glycolysis
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation

44. Why is albinism inheritnace varialbe due to...
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Locus heterogeneity - ocular albinism is x- linked recessive
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
1 kind with multiple subunits

45. How does ouabain work
Inhibits the Na/K pump by binding the K side
CAG - 4
IDL
Four

46. How do odd chain fatty acids participate in gluconeogenesis
Carbomoyl phosphate synthetase II
After day 1
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Purines= A - G pyrimidine = C - T (U)

47. What do DNA topoisomerases do
Thymic - parathyroid and cardiac
Attachment of ubiquitin to defective proteins tag them for breakdown
Creat a nick in the helix to relieave supercoils created during replication
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US

48. Inhibition of thymidilate synthase and and DHFR lead to decrease In what substance
Makes RNA primer on which DNA poly III can initiate replication
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
DTMP
Wernicke - korsakoff - dry and wet beriberi

49. What is the RDE of TCA cycle
Lysine and arginine
Isocitrate dehydrogenase
Vit K antagonist
1 -25 OH2 D3 = calcitriol

50. characterize autosomal domint inheritance
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Inc insulin - dec cAMP - dec PKA
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Met - val - arg his