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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 RNAi used for
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
DsRNA promotes degradation of target mRNA knocking down gene expression
75 to 90 - cloverleaf
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision

2. Which end of the tRNA is the amino acid bound to...

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3. What does apoE do
Inhibits 50S peptidyltransferase
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Phosphorylation - glycosylation - hydroxylation
Mediates extra remnant take up

4. What neuroanatomical strutures are injured in wernicke - korsakoff
Glycine - aspartate - glutamine
Initiate chains
Medial dorsal nucleus of thalamus - mamillary bodies
Fed

5. What is the amino acid precursor for porphyrin and heme
Glycine
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
HDL
Tropoelastin with fibrillin scafolding

6. Describe the structure of cilia
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Glutamate
9+2 arrangement of microtubules
Removal of N or C termal propeptides from zymogens to generate mature proteins

7. Type IV collagen
Not all individuals with a mutant genotype show the mutant phenotype
Basement membrane or basal lamina
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Four

8. What shape does the RNA generate during splicing and why?
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Lariat shape in order and remove intron precisely and join 2 exons
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
Dopamine beta hydroxylase

9. What does CATCH 22 stand for and What causes is...
Mediates extra remnant take up
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
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Neither of 2 alleles is dominant - blood groups

10. What kind of branches do glycogen branches have
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Metanephrine
Alpha 1 -6 and alpha 1 -4

11. What is the physiologic role of dystrophin
Procollagen - triple helix of 3 alpha collagen chains
Anchor muscle fibers - primarily in skeletal and cardiac muscle
Vincritsine/vinblastine
Unmethylated - newly synthesized - HNPCC

12. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
Adds 2 carbon with the help of biotin
Karyotyping
Proton gradient
Familial hypercholesterolemia - hyperlipidemia type IIA

13. What order kinetics does EtOH dehydrogenase have
FAP
HGPRT - defective purine salvage - excess uric acid production
Acetoacetate and beta hydroxybutyrate
Zero

14. Type IV BM
4 under the floor
B100
Free ribosomes
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

15. What converts DOPA to dopamine
Histidine
CG- 3 > AT-2 - More CG content - melting point goes up
Kidney - ears - eyes
Dopa decarboxylase

16. What is the activated carrier for 1 carbon units
THFs
ADPKD
CAG - 4
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine

17. Which are the basic amino acids
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
Anabolic processes as a supply of reducing equivalents
Arg - lys - his - arg is most basic - has has no charge at body pH
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer

18. What is the name is fxn of vit B3
HMG- CoA reductase
Niacin - constituent of NAD and NADP - derived from tryptophan
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

19. What is the RDE of gluconeogenesis
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
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
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Fructose 1 -6 bisphosphate

20. How is ammonium transported from muscle to the liver for urea cycle
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Von Gierke's - Pompe - Cori - McArdle
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
CG- 3 > AT-2 - More CG content - melting point goes up

21. What is the RDE of glycogen synthesis
Accelearted muscle breakdown
Liver - ovaries - seminal vesicles
Glycogen synthase
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive

22. What enzyme turns ROS to H2O2
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Heterochromatin = HighlyCondensed
Superoxide dismutase

23. what gene is implicated in fragile X syndrome - and What is the mutation
Core proteins
FMR1 gene - methylation - associated with chromosomal breakage
Phenylalanine hydroxylase
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis

24. progressive neurodegeneration - hepatosplenomegaly - cherry red spot on macula - foam cells
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Neimann - pick - sphingomyelinase - sphingomyelin - AR
Inc glucagon - inc cAMP - inc PKA
Alkaptonuria - may have debiliating arthralgias

25. What induces pyruvate kinase
RRNA
Inc vit B6
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
F16BP

26. Where is vit B12 found
Schilling test
Breaks down acyl - coa to acetyl coa groups in mito
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase

27. What is the result of vit B5 def
3' end (with CCA)
Arginine
Dermatitis - enteritis - alopecia - adrenal insuff
Dermatitis - alopecia - enteritis

28. What does the mutation in the gene cause in protein synthesis
Abnormal protein folding - degradation before reaching cell surface
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Read from a fixed starting point as a continuous sequence of bases
Phenylethamolamine N methyl transferase

29. What shuttle is used in fatty acid degredation and What does it move and From where to where
Mebendazole/thiabendazole
B100
Assistance of upper extremities to stand up
Carnitine shuttle - acyl - coa from cyto to mito

30. Accurate base pairing is required only in the first two nucleotide positions of an mRNA codon - so conds differeing in the 3rd position may code for the same tRNA/AA due to degenerate genetic code
Degredation of TG circulating in chylomicrons and VLDLs
Phenylketones in urine
Wobble
Phosphofructokinase 1

31. cell signaling defect of fibroblast growth factor (FGF) receptor 3 - results in dwarfism - short limbs - head/trunk nl size - associated with advanced paternal age
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Achondroplasia
Liver hepatocytes and steroid producing cells of the adrenal cortex
DNA

32. What is the order of severity for the different types of mutations
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Nonsense > missense > silent
HVA
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it

33. What do the single stranded binding proteins do
Accelearted muscle breakdown
Nissl body - enzyme and NTs
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Prevent strands from reannealing

34. Which anti breast cancer drugs work on micortubules
Four
Stop codon is recognized by release factor - and completed protein is released from ribosome
Paclitaxel
HVA

35. Type II cartilage
RRNA
B100 and E
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
CarTWOlage

36. How is vit D stored
Unmethylated - newly synthesized - HNPCC
Accelearted muscle breakdown
Neither of 2 alleles is dominant - blood groups
25OHD3

37. What is I cell disease
Vit K antagonist
Neural tube
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes

38. What is the RER called in neurons and What is made there
Alpha and beta tubulin - dimers have two GTP bound
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Pyruvate to oxaloacetate (3C to 4C)
Nissl body - enzyme and NTs

39. What converts limit dextran to glucose
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Debranching enzyme
HGPRT - defective purine salvage - excess uric acid production

40. What lab procedure is used to amplify desired fragment of DNA and What are the 3 steps
Fasting
Each codon specifies only 1 amino acid
PCR - denaturation - annealing - elongation
1 -25 OH2 D3 = calcitriol

41. What is chediak higashi
32 - malate aspartate shuttle
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
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
Microtuble polymerization defect causing a dec in phagocytosis results in recurrent pyogenic infections - partial albinism - and peripheral neuropathy

42. The pyruvate dehydorgenase complex serves In what reaction: reactants
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
Pyruvate - NAD+ - CoA
Gamma carboxylation of glutamic acid residues on various proteins concerned with blood clotting - synthesized in intestinal flora
Locus heterogeneity - ocular albinism is x- linked recessive

43. What does vit B3 def result in
30 - 50 - 70
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Leu - lys

44. What happens on the nonoxidative arm of the HMP shunt and What is the key enzyme and cofactor
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
Males are infertile due to bilateral absence of vas deferens
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Superoxide dismutase

45. In a 1000 meter run - Where does energy come from
African Americans and Asians
Proline and lysine - vit C
Same as sprint + OXPHOS
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR

46. What is codominance and give an example
Neither of 2 alleles is dominant - blood groups
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
More than 1 codon may code for the same amino acid

47. depression - progressive dementia - choreiform movements - caudate atrophy and dec levels of GABA and ACH in the brain
Pseudomonas and s aureus
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Huntingtons
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

48. What is the RDE of cholesterol synthesis
HMG- CoA reductase
African Americans and Asians
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Glutamate

49. What does lipoprotein lipase do
CAG
The triphosphate bond
Degredation of TG circulating in chylomicrons and VLDLs
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two

50. How does abetalipoproteinemia present and What is the defect
FMR1 gene - methylation - associated with chromosomal breakage
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
Diphyllobothrium latum
Leu - lys