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Biochemistry

Instructions:

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 causes Marfan syndrome
Liver - also in kidney and gut epithelium
Accelearted muscle breakdown
Malapsorption syndromes like sprue or CF or mineral oil intake
Defect in fibrillin

2. What does the passage of electrons result in that when coupled to OXPHOS drives the production of ATP
Antioxidant - protects RBCs and membrances from free radical damage
Proton gradient
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

3. How do tetracyclines work
HMP shunt
Removal of N or C termal propeptides from zymogens to generate mature proteins
Oxidized hemoglobin precipiated within RBCs
Bind 30s subunit preventing attachment of aminoacyl - tRNA

4. What tissues have both enzymes of sorbitol metabolism
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Liver - ovaries - seminal vesicles
PCR - denaturation - annealing - elongation
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

5. How do fluoroquinolones work
LCAT (lecithin cholesterol acyltransferase)
Inhibit DNA gyrase specific for prokaryotic topoisomerase
MRNA
Unmethylated - newly synthesized - HNPCC

6. characterize x linked recessive
Ketone - methyl
Sons of heterozygous mothers have 1/2 half chance of being affected - no male to male transmission - and often more severe in males - heterozygous females may be affected
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Colchicine

7. A small proportion of Down syndrome is due to What two genetic events
Carnitine shuttle - acyl - coa from cyto to mito
Tropoelastin with fibrillin scafolding
32 - malate aspartate shuttle
Robertsonian translocation and mosaicism

8. What does a carboxylase do
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Adds 2 carbon with the help of biotin
Alanine
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid

9. What ribosomes do eukaryotes have
40 - 60 - 80
Glycogen phosphorylase
Methionine encode by only 1 codon (AUG)
Ile - phe - thr - trp

10. What converts limit dextran to glucose
9+2 arrangement of microtubules
Debranching enzyme
Pyruvate to oxaloacetate (3C to 4C)
Citrate - acetyl coa from mito to cyto

11. What is the pathway in the fed state leading to dec FBPase -2 and inc PFK-2
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Inc insulin - dec cAMP - dec PKA
Defect in fibrillin
FMR1 gene - methylation - associated with chromosomal breakage

12. What does vit C def cause
9+2 arrangement of microtubules
No
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation

13. Type I bone
Wrinkles and acne
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
BOne
Palate - facial and cardiac defects

14. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
Fasting
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
HGPRT - defective purine salvage - excess uric acid production
Marfans

15. How many ATP are produced by anearobic glycolysis per molecule of glucose
Cyclin dependent kinases;constitutive and inactive
Breaks down acyl - coa to acetyl coa groups in mito
Two
THFs

16. In which single strand DNA repair mechanism do specific endonucleases release the oligonucTIDE containing bases and DNA poly and ligase fill and reseal - and what disease occures when this is mutated
Inhibits the Na/K pump by binding the K side
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Specific glycosylases - AP endonuclease
Exercise: inc NAD/NADH - inc ADP - inc Ca

17. What does a defective Cl channel do
Exercise: inc NAD/NADH - inc ADP - inc Ca
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Change resulting in early stop codon
Type II

18. Of the four possible fates for pyruvate - which one is a transition from glycolysis to TCA cycle
Acetyl - CoA
Must be both activated and inactivated for cell cycle to progress
Makes RNA primer on which DNA poly III can initiate replication
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast

19. What are possilbe presentation for galactokinase def
Chylomicrons
NAD+
Failure to track objects or develop a social smile
Alpha - ketoglutarate dehydrogenase complex

20. What is the RDE of fatty acid synthesis
Isocitrate dehydrogenase
Disorder of aromatic amino acid metabolism
Acetyl - CoA carboxylase (ACC)
Neither of 2 alleles is dominant - blood groups

21. What are the irreversible enzymes of gluconeogenesis
Alpha - ketoglutarate dehydrogenase complex
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O

22. Where is vit A found in the diet
Lariat shape in order and remove intron precisely and join 2 exons
Glycogen synthase
Neg to pos
Liver and leafy veggies

23. What creates the musty body odor in PKU
Williams syndrome
Disorder of aromatic amino acid metabolism
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
2pq

24. What is maternal PKU
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
BOne
Chylomicrons
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects

25. What is the defect in fructose intolerance and What does it cause
L form
Result from phagocytic removal of heinz bodies my macs - G6PD def
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Isocitrate dehydrogenase

26. What is disulfiram used for
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Malonyl coa
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Tuberous sclerosis

27. characterize autosomal recessive inheritance
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
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
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease

28. 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
Inhibits RNA polymerase II - found in death cap mushrooms
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Euchromatin

29. Gene imprinting implies that How many alleles are active at a single locus
Degredation of dietary TG in small intestine
One
Pseudomonas and s aureus
2 -4 DNP - aspirin

30. RNA poly can't proofread - but What can it do
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
3' end (with CCA)
Dec DNA - dec lymphos leads to SCID
Initiate chains

31. How many rings do pyrimidines have
P+q = 1
Inhibits the Na/K pump by binding the K side
1 ring
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase

32. What enzyme results in classic galactosemia and What is the clinical
Carnitine acyltransferase I
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Two

33. Type III collagen
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
5' of the incoming nucleotide
Semiconservative - continuous and discontinuous strands (okazaki fragments)
SnRNPs and other proteins

34. How does ethanol induce hypoglycemia
Exercise: inc NAD/NADH - inc ADP - inc Ca
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
Carbomoyl phosphate synthetase II
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

35. What is the structure of elastin
Exons
5' of the incoming nucleotide
FMR1 gene - methylation - associated with chromosomal breakage
Tropoelastin with fibrillin scafolding

36. What CETP do
Fibrofatty replacement of muscle - cardiac myopathy
Familial hypercholesterolemia - hyperlipidemia type IIA
Vit K antagonist
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)

37. What rxn does propionyl - CoA carboxylase catalyze
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Hepatic glycogenolysis - adipose tissue release of FFA - muslce and liver FFA - hepatic gluconeogenesis from peripheral tissue lactate and alanine and from adipose tissue glycerol and proprionyl - coA (odd chain FFA)
Alanine

38. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
3' end (with CCA)
EtOH dehydrogenase and acetaldehyde dehydrogenase
Liver - also in kidney and gut epithelium
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision

39. What are the purely ketogenic amino acids
Initiate chains
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Antioxidant - protects RBCs and membrances from free radical damage
Leu - lys

40. What does Ehlers Danlos cause and why
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Facial flushing
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

41. What is the name is fxn of vit B3
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
Niacin - constituent of NAD and NADP - derived from tryptophan
Glycine
Exons

42. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
After citruline
Phosphofructokinase 1
Chylomicrons
Euchromatin

43. What is the defect in cystinuria
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Lariat shape in order and remove intron precisely and join 2 exons
VMA
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

44. What substance inside the cell serves to oxidize glutatione
Peroxide
Binds to LDL receptor - mediates VLDL secretion
Defect in fibrillin
Inhibit DNA gyrase specific for prokaryotic topoisomerase

45. What does helicase do
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Unwinds DNA template at replcation fork
Myeloperoxidase
Failure to track objects or develop a social smile

46. Why can't even chain fatty acids produce new glucose
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
They yield only acetyl - CoA equivalents
3' end (with CCA)
Colchicine

47. NADPH are used In what 4 things
Oligomycin
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
Mcardle's - skeletal muscle glycogen posphorylase
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

48. What fxn does glucokinase serve in the liver
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
MRNA - tRNA
The triphosphate bond
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

49. congenital deficiency of homogentisic acid oxidase in the degradative pathway of tyrosine to fumarate leading to dark connective tissue - brown pigmented sclera - urine turns black on standing - dz and worst complication
MRNA - tRNA
Phenylethamolamine N methyl transferase
Alkaptonuria - may have debiliating arthralgias
Pyruvate - NAD+ - CoA

50. What is anticipation and give an example
Oral uridine administration
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Neimann - pick - sphingomyelinase - sphingomyelin - AR