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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. A small proportion of Down syndrome is due to What two genetic events
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT
Robertsonian translocation and mosaicism
VLDL
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism

2. In eukaryotes - What does RNA poly III make
Hypoglycemia
Dermatitis - enteritis - alopecia - adrenal insuff
TRNA
Immotile cilia due to dynein arm defect - male and femail infertile - bronchiectasis - recurrent sinusitis - associated with situs inversus

3. What does biotin def cause
Malabsorption and steatorrhea (ADEK)
Phosphofructokinase 1
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Dermatitis - alopecia - enteritis

4. How is ATP used by the cell
ATP hyrdolysis couple to energetically unfavorable rxns
CarTWOlage
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
2pq

5. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
Lysine and leucine
Diphyllobothrium latum
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

6. RNA poly can't proofread - but What can it do
THFs
3' end (with CCA)
Initiate chains
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

7. What metabolic rxns occur in the mitochondria
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
SNP
1 -25 OH2 D3 = calcitriol
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS

8. Which step in the de novo purine and pyrimidine synthesis pathway requires aspartate - glycine - glutamine and THF
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss
Achondroplasia
Ribose 5- P to PRPP
Alpha and beta tubulin - dimers have two GTP bound

9. Which anticancer drugs work on microtubules
Vincritsine/vinblastine
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Glycolysis and aerobic respiration
Paclitaxel

10. What enzyme turns ROS to H2O2
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Rotenone - CN- - antimycin A - CO
Evident in first few days of life - can present last onest - excess carbamoyl phosphate converted to orotic acid - orotic acid in blood and urine - dec BUN and symptoms of hyerpammonemia
Superoxide dismutase

11. central and peripheral demyelination with ataxia and dementia
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Degredation of dietary TG in small intestine
Mediates extra remnant take up
Inhibits 50S peptidyltransferase

12. What step of uric acid synthesis does xanthine oxidase catalyze
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
They yield only acetyl - CoA equivalents
Hypoxanthine to xanthing and xanthine to uric acid

13. What is the pathway in the fed state leading to dec FBPase -2 and inc PFK-2
Dec DNA - dec lymphos leads to SCID
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Inc insulin - dec cAMP - dec PKA
Result from phagocytic removal of heinz bodies my macs - G6PD def

14. What is RNAi used for
Deamination
Inhibits 50S peptidyltransferase
Eu - methionine - pro - formyl - methionine
DsRNA promotes degradation of target mRNA knocking down gene expression

15. What is DNA cloning and How do you do it?
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Sucrose = glucose + fructose - lactose = glucose + galactose
AR
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA

16. How is vit D stored
Fructose 1 -6 bisphosphate
Pyroxidine - converted to pyroxidine phosphate a cofactor used in transamination - decarboxylation - glycogen phosphorylase - cystathionine synthesis and heme synthesis - required for synthesis of niacin and tryptophan
25OHD3
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization

17. What activates the pyruvate dehydrogenase complex
Exercise: inc NAD/NADH - inc ADP - inc Ca
African Americans and Asians
Alpha 1 -6 and alpha 1 -4
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)

18. What is loss of heterozygosity and give an example
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
Sulfation
Uses ATP to add high energy phophate group onto substrate
Glycine - aspartate - glutamine

19. What does acetyl - CoA become before becoming palmitate
ATP and alanine
Asp and Glu
Assistance of upper extremities to stand up
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

20. What are the findings in orotic aciduria
Eu - methionine - pro - formyl - methionine
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Phenylketones in urine
Inc vit B6

21. Which are the acidic amino acids
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Asp and Glu
Pyruvate - NAD+ - CoA
Phenylethamolamine N methyl transferase

22. What shuttle is used in fatty acid degredation and What does it move and From where to where
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Fasting
Carnitine shuttle - acyl - coa from cyto to mito

23. Type IV collagen
Basement membrane or basal lamina
Same as sprint + OXPHOS
Fructose 1 -6 bisphosphate
Post to neg

24. In a 1000 meter run - Where does energy come from
Neurofibromatosis type 1 (von Recklinghausens disease)
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Same as sprint + OXPHOS
5' of the incoming nucleotide

25. What is the RDE of fatty acid oxidation
Carnitine acyltransferase I
Glycogen synthase
Tryosine hydroxylase
Mediates extra remnant take up

26. How is Lesch Neyhan inherited
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Eu - methionine - pro - formyl - methionine
Oral uridine administration
X- linked recessive

27. What is the source of energy in the fasting state between meals
CFTR gene - 7 - Phe 508
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
B100
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year

28. How are the many staggered tropocollagen molecules reinforced
Sulfation
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
THFs
Covalent cross - linking by lysyl oxidase to make collagen fibrils

29. What is the amino acid precuros for niacin and serotonin/melatonin
Tryptophan
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Neither of 2 alleles is dominant - blood groups
Familial hypercholesterolemia - hyperlipidemia type IIA

30. characterize autosomal recessive inheritance
Liver - also in kidney and gut epithelium
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
B-100 - CII and E
Pyruvate to oxaloacetate (3C to 4C)

31. What converts limit dextran to glucose
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Chylomicrons
Base + ribose
Debranching enzyme

32. If two alleles are present - but the active allele is deleted - what happens
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Disease
Cartilage - hyaline - vitreous body - nucleus pulposus
ATP

33. What stretch of DNA that alters gene expression by binding of transcription factors
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Enhancers
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Inc dicarboxylic acids - dec in glucose and ketones

34. What co - factors are required for the pyruvated dehydrogenase complex
VLDL
Glycine
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Wobble

35. What is the hardy weinber heterozygote prevalence
Elastase - inhibited by alpha1 antitrypsin
Oxalacetate
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
2pq

36. How many rings do purines have
Nonsense > missense > silent
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
2 rings

37. What does the mutation in the gene cause in protein synthesis
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
Abnormal protein folding - degradation before reaching cell surface
Avidin

38. What does vit E def cause
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Williams syndrome
Must be both activated and inactivated for cell cycle to progress
Malapsorption syndromes like sprue or CF or mineral oil intake

39. What sugar is sorbitol converted to and via what enzyme - and What can happen in cells lacking this enzyme
Lactate
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
APKD1 on chromosome 16
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes

40. What is the Name and fxn of vit B5
Base + ribose + phosphate (3' -5') phosphodiester bond
B-100 - CII and E
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
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase

41. What is the exception to genetic redundancy
Asp and Glu
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
Removes phosphate group from substrate
Methionine encode by only 1 codon (AUG)

42. 1 g of protein or cabrohydrate = ?kcal
Four
Acetyl - CoA to malonyl - CoA (2C to 3C)
Palate - facial and cardiac defects
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet

43. What is sorbitol - how and why is it made
Malapsorption syndromes like sprue or CF or mineral oil intake
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
Alcohol version of glucose - can trap glucose in cell - aldose reductase

44. What CETP do
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Cleft palate - cardiac abnl - pregs test
THFs
Pyruvate to oxaloacetate (3C to 4C)

45. Broadly - What can cause fat - soluble vitamin deficiencies
Intermediate filaments
PFK - rate limiting enzyme
Consesus sequenec of base pairs
Malapsorption syndromes like sprue or CF or mineral oil intake

46. Which type of chromatin is less condensed - transcriptionally active - sterically accesible
Disease
Euchromatin
P+q = 1
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia

47. What are the water soluble vitamins - which ones are stored
4 under the floor
Malonyl coa
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)

48. What is locus heterogeneity and give an example
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Unmethylated - newly synthesized - HNPCC
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Neurofibromatosis type 1 (von Recklinghausens disease)

49. Where are FADH2 electrons transferred to...
X linked frame shif mutation
Lacks glucose 6 phophatase
Neg to pos
Comlex II

50. Delivers hepatic cholesterol to peripheral tissues - formed by LPL modification of VLDL in the peripheral tissue - taken up by target cells via RME
Euchromatin
Phenytoin - MTX - and sulfonamides
LDL
Tryosine hydroxylase