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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 enzyme turns ROS to H2O2
Q -
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Superoxide dismutase
Accelearted muscle breakdown

2. What substance inside the cell serves to oxidize glutatione
Peroxide
Acetoacetate and beta hydroxybutyrate
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
30 - glycerol -3- phosphate shuttle

3. Where are cytosolic and organellar proteins made
Unmethylated - newly synthesized - HNPCC
Site of steroid synthesis and detoxification of drugs and poisons
Free ribosomes
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

4. How does abetalipoproteinemia present and What is the defect
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
Dermatitis - alopecia - enteritis
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism

5. What does a western blot use for its sample
Tropoelastin with fibrillin scafolding
Free ribosomes
Cofactor for LPL
Protein

6. How does cytosine become uracil
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Deamination
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

7. What test is used for B12 def
VLDL
G6PD
Schilling test
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

8. What is the amino acid precuror for creatine - urea and nitric oxide
G6PD
Arginine
Inc insulin - dec cAMP - dec PKA
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)

9. bilateral acoustic schwannomas - juvenile cataracts
Lysine and leucine
Males are infertile due to bilateral absence of vas deferens
NF2 on chromosome 22
Keep glutathione reduced so it can detoxify free radicals and peroxides

10. What neuroanatomical strutures are injured in wernicke - korsakoff
Phenytoin - MTX - and sulfonamides
Particular sequence of DNA where replicatino begins - may be single of multiple
NADPH
Medial dorsal nucleus of thalamus - mamillary bodies

11. What are uncoupling agents
Inc permeability of membrane causing a dec in proton gradient and inc in O2 consumption - ATP synthesis stops - but electron transport continues to produce heat
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Colchicine
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

12. Why can't even chain fatty acids produce new glucose
They yield only acetyl - CoA equivalents
HGPRT - defective purine salvage - excess uric acid production
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

13. How does chloramphenicol work
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
PFK - rate limiting enzyme
Inhibits 50S peptidyltransferase
Inc melt - dec fluidity

14. telangiectasia - recrrent epistaxis - skin discolorations - AVMs
Alpha and beta tubulin - dimers have two GTP bound
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Transmitted only through mother - all offspring of affected females may show signs of disease

15. How does ouabain work
Antioxidant - protects RBCs and membrances from free radical damage
Inhibits the Na/K pump by binding the K side
Carbomoyl phosphate synthetase II
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes

16. What rxn does propionyl - CoA carboxylase catalyze
Alkaptonuria - may have debiliating arthralgias
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Plasma membrane - 3Na out - 2K in - ATP on cytoplasmic side
Acetly- CoA - CO2 - NADH

17. What is the result of vit B5 def
Palate - facial and cardiac defects
Dermatitis - enteritis - alopecia - adrenal insuff
Consesus sequenec of base pairs
Dopamine beta hydroxylase

18. What is DNA cloning and How do you do it?
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
ATP
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
HMG- CoA reductase

19. What is a nonsense mutation
Change resulting in early stop codon
Mcardle's - skeletal muscle glycogen posphorylase
Neuralgia
Glycogen phosphorylase

20. FAP is due to deletion On what gene On what chromosome
Inc melt - dec fluidity
Particular sequence of DNA where replicatino begins - may be single of multiple
NF2 on chromosome 22
APC on chromosome 5

21. What is the RDE of ketogenesis
Free ribosomes
They yield only acetyl - CoA equivalents
HMG- CoA synthase
Locus heterogeneity - ocular albinism is x- linked recessive

22. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
Pseudomonas and s aureus
Rb and p53
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA

23. What rxn creates ATP
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Mental retardation - flat facies - prominent epicanthal folds - simian crease - gap between 1st 2 toes - duodenal atresia - congenital heart disease (ASD) - inc risk of All and Alzheimers
Phenytoin - MTX - and sulfonamides

24. What produces NADPH
Malapsorption syndromes like sprue or CF or mineral oil intake
Glycogen and FFA oxidation; glucose conserved for final sprinting
Glutamate
HMP shunt

25. In a 1000 meter run - Where does energy come from
Same AA - often base change in 3rd position of codon (tRNA wobble)
Same as sprint + OXPHOS
HGPRT - defective purine salvage - excess uric acid production
Fibroblast

26. What is the RDE of TCA cycle
EtOH dehydrogenase and acetaldehyde dehydrogenase
Uses ATP to add high energy phophate group onto substrate
Hypoxanthine to xanthing and xanthine to uric acid
Isocitrate dehydrogenase

27. What does a mischarge tRNA do
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Alpha1 antitrypsin
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Reads usual codon but inserts wrong AA

28. Is there any requirement for homology in NHEJ
No - its non homologous
Change resulting in early stop codon
NF2 on chromosome 22
Arg - lys - his - arg is most basic - has has no charge at body pH

29. Where is vit B12 found
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Marfans
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Phosphofructokinase 1

30. What initiates protein synthesis
OTC has hyperammonemia - orotic aciduira does not
High output cardiac failure - dilated cardiomyopathy - edema
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility

31. What is trimming
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
Removal of N or C termal propeptides from zymogens to generate mature proteins
Assistance of upper extremities to stand up

32. What does the ELISA test for
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Cre - lox system
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Antigen - antibody reactivity - can look for antigen or antibody in patients blood

33. What is the breakdown product of dopamine
HVA
Pyruvate to oxaloacetate (3C to 4C)
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Inc glucagon - inc cAMP - inc PKA

34. What is Gowers maneuver
Orotic acid to UMP
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
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
Assistance of upper extremities to stand up

35. What is the rate limiting enzyme in cholesterol synthesis
CTG
Oligomycin
Abnormal protein folding - degradation before reaching cell surface
HMG- CoA (HMG- CoA to mevalonate

36. What is the activated carrier for electrons
CGG
NADH - NADPH - FADH2
25OHD3
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

37. For eukaryotes - Where does replication begin?
Night blindness - dry skin
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Hypoglycemia
Consesus sequenec of base pairs

38. antbiotic controlled promoter to induciblly manipulate genes at specific developmental points
NADH - NADPH - FADH2
Cre - lox system
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
L form

39. How are the many staggered tropocollagen molecules reinforced
Covalent cross - linking by lysyl oxidase to make collagen fibrils
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Infection - free radicals generated by inflammatory response

40. What is pseudohypertrophy in the calf a result of - and What are the cardiac manifestations
Fibrofatty replacement of muscle - cardiac myopathy
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
Vincritsine/vinblastine
Actin and myosin

41. What is the Name and function of vit B2
Inhibits 50S peptidyltransferase
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Acetoacetate and beta hydroxybutyrate

42. What causes B12 def
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Familial hypercholesterolemia - hyperlipidemia type IIA
Actin and myosin

43. How do labile celss grow and regenerate and What are examples
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
P+q = 1
Never go to G0 - divide rapidly with a short G1 - bone marrow - gut epi - skin - hair follicles
III - joint dislocation - anuerysms - organ rupture

44. What does hartnups disease cause
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
B48 - AIV - CII - E
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate

45. In prokaryotes - What does makes the different types of RNA
1 kind with multiple subunits
Ile - phe - thr - trp
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase

46. What is linkage disequilibrium
Acetyl - CoA to malonyl - CoA (2C to 3C)
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Oxidizes substrate

47. metaphse chromosomes are stained - ordered and numbered according to morphology - size - arm length ratio - banding pattern
Karyotyping
Polycystic liver disease - berry aneurysm - mitral valve prolapse
B6
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it

48. An inability to convert orotic acid to UMP would be caused by a deficiency either of which two enzymes

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49. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Liver - also in kidney and gut epithelium
De novo pyrimidine synthesis and urea - ornithine transcarbamoyl def in the urea cycle leads to a build of CP - then converted to orotic acid in pyrimidine synthesis pathway

50. What are the fat soluble vitamins and What does their absorption depend on...
Wrinkles and acne
Creat a nick in the helix to relieave supercoils created during replication
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Sucrose = glucose + fructose - lactose = glucose + galactose