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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 the smallest mutation a mircoarray can detect
Wrinkles and acne
Neg to pos
SNP
Anchor muscle fibers - primarily in skeletal and cardiac muscle

2. ADPKD is associated with What additional conditions
Adds 2 carbon with the help of biotin
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Phosphorylation - glycosylation - hydroxylation
Vincritsine/vinblastine

3. What causes biotin def
Karyotyping
Antibiotic use or excessive ingestion of raw eggs
P2 +2pq+ = 1
After citruline

4. How do stable (quiescent) cells grow and regenerate and What are examples
Schwann cells - lens - retina - kidneys
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
5' to 3'
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles

5. What does a dehydrogenase do
Exercise: inc NAD/NADH - inc ADP - inc Ca
Cri du chat
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Oxidizes substrate

6. What are the function of vit C
MRNA
Prevent strands from reannealing
Antioxidant - facilitates iron absorption by keeping iron in the Fe2+ reduced state - necessary for hydroxylation of proline and lysine collagen bridges - necessary for dopamine beta hydroxylase which converts DA to NE
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea

7. What does Ehlers Danlos cause and why
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
APC on chromosome 5
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
TTP

8. What activates the pyruvate dehydrogenase complex
Protein kinase A
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Exercise: inc NAD/NADH - inc ADP - inc Ca
Cofactor for LPL

9. What is a nonsense mutation
Change resulting in early stop codon
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
Lariat shape in order and remove intron precisely and join 2 exons
Initiate chains

10. What is the source of energy in the fasting state between meals
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA
CAG - 4
Terminal regions - tropocollagen
Sucrose = glucose + fructose - lactose = glucose + galactose

11. What is the structure of elastin
Tropoelastin with fibrillin scafolding
HMP shunt
Robertsonian translocation and mosaicism
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue

12. Which direction does kinesin go
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
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
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
Neg to pos

13. What creates the musty body odor in PKU
Disorder of aromatic amino acid metabolism
Liver - also in kidney and gut epithelium
Not all individuals with a mutant genotype show the mutant phenotype
Nissl body - enzyme and NTs

14. What are the blood glucose levels maintained by for days 1-3
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine
B100 and E
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)
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor

15. Type I collagen
Carbomoyl phosphate synthetase II
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
Grows slowly - collapses quickly

16. What does the TCA cycle produce per 1 acetyl CoA
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Specific glycosylases - AP endonuclease
More than 1 codon may code for the same amino acid
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first

17. Gene imprinting implies that How many alleles are active at a single locus
Dopamine beta hydroxylase
Polyneuritis - symmetrical muscle wasting
One
Modifies N- oligosaccharides

18. telangiectasia - recrrent epistaxis - skin discolorations - AVMs
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
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
L form
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)

19. In which direction is protein synthesized
Autosomal recessive diseases
Hartnup disease - dec tryptophan absoprtion - malignant carcinoid syndrome (inc tryptopha metabolism) and INH (dec vit B6)
Glutamate
N to C

20. What metabolic rxns occur in the cytoplasm
Ribos first then deoxyribos with ribonucleotide reductase
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
Arginine
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)

21. What are the teratogenic effects of vit A and What test must be ordered before starting a woman on isotreitinoin for severe acne
Cleft palate - cardiac abnl - pregs test
Leu - lys
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis

22. What is a silent mutation
In ER - glucose 6- P to glucose
Catabolic processes to carry reducing equivalents away as NADH
ATP and methionine
Same AA - often base change in 3rd position of codon (tRNA wobble)

23. What trinucleotide repeat in Huntingtons and what chromosome is it found on...
CAG - 4
Tryptophan
Actin and myosin
II - VII - IX - X (1972) protein C and S

24. What is sorbitol - how and why is it made
Alcohol version of glucose - can trap glucose in cell - aldose reductase
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Mutated dystrophin gene - less severe - adolescence

25. What bone disorder has x linked dominant inheritance
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Glutamine PRPP amidotransferase
Basement membrane or basal lamina

26. What are the functinos of vitamin A
RRNA
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Glycogenolysis to form glucose

27. Why can't muscle produce in gluconeogenesis
TTP
Inc insulin - dec cAMP - dec PKA
Lacks glucose 6 phophatase
Diphyllobothrium latum

28. What causes Edwards syndrome and What is it
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
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
Citrate - acetyl coa from mito to cyto

29. What enzyme turns ROS to H2O2
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Adenosine to inosine
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Superoxide dismutase

30. What is the trinucleotide repeat in fragile X
Coarse facial features - clouded corneas - restricted joint movements - high plasma levels of lysosomal enzymes - often fatal in childhood
Mediates extra remnant take up
Collagen
CGG

31. How are the many staggered tropocollagen molecules reinforced
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
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
Acetoacetate and beta hydroxybutyrate

32. What is the RDE of cholesterol synthesis
HMG- CoA reductase
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
Inc dicarboxylic acids - dec in glucose and ketones
Nature and severity of phenotype vary from 1 individual to another - NF type 1

33. What shuttle is involved in fatty acid synthesis and What does it move From where to where
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
Oral uridine administration
Acetyl - CoA
Citrate - acetyl coa from mito to cyto

34. In mismatch repair - which strand is recognized and In what hereditary syndrome is this defective
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Unmethylated - newly synthesized - HNPCC
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
PFK - rate limiting enzyme

35. What does acetyl - CoA become before becoming palmitate
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
Von hippel lindau - 3
VLDL
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

36. What is the TX for hyper ammonemia
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
B-100 - CII and E
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
DTMP

37. Which antihelminthe drugs work on microtubules
CTG
Mebendazole/thiabendazole
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
Ribos first then deoxyribos with ribonucleotide reductase

38. What rxn creates ATP
ATP and alanine
Glycine
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Fibrofatty replacement of muscle - cardiac myopathy

39. What is trimming
Removal of N or C termal propeptides from zymogens to generate mature proteins
Deamination
Makes RNA primer on which DNA poly III can initiate replication
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

40. Where is EtOH dehydrogenase located
Inhibits 50S peptidyltransferase
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Cytosol

41. In what direction are DNA and RNA synthesized

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42. What is the energy source after day 3 of starvation
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Changed AA (convservative - new AA is similar in chemical structure)
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
X linked frame shif mutation

43. Which type of chromatin is condensed - transcriptionally inactive - sterically inaccessible?
ATP - citrate
Heterochromatin = HighlyCondensed
Orotate precursor - with PRPP added later
Result from phagocytic removal of heinz bodies my macs - G6PD def

44. What are the 2 distinct phases of the HMP shunt and How many ATP are used and produced
CGG
Oxidative and nonoxidative - no ATP produced or used
RNA
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility

45. What are bite cells and when do you see them
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
B6
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Result from phagocytic removal of heinz bodies my macs - G6PD def

46. What is the hardy weinber heterozygote prevalence
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
O- oligosaccharaides
2pq
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

47. How do you diagnose CFTR
Acetyl - CoA to malonyl - CoA (2C to 3C)
Inc Cl - in sweat
2 -4 DNP - aspirin
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond

48. How do odd chain fatty acids participate in gluconeogenesis
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
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
Chronic granulomatous disease - no respiatory burst - no formatino of ROS

49. How does ouabain work
9+2 arrangement of microtubules
Inhibits the Na/K pump by binding the K side
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
B6

50. The pyruvate dehydrogenase complex serves In what reaction: products
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Acetly- CoA - CO2 - NADH
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms
Phenylalanine hydroxylase