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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. How many rings do purines have
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Williams syndrome
Hypoxanthine to xanthing and xanthine to uric acid
2 rings

2. Where does gluconeogenesis primarily happen and What are other sites where the enzymes are located
Base + ribose
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Exons
Liver - also in kidney and gut epithelium

3. Which tumor suppresors inhibit G1 to S progression - where mutations result in unrestrained growth
Rb and p53
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
Histidine
Alpha and beta tubulin - dimers have two GTP bound

4. How many nucTIDEs is a tRNA and What does the secondary sturcture form
Glycolysis and the glycogen synthesis in the liver - hexokinase or glucokinase
Receptor tyrosine kinases - protein phosphatase - takes phosphate off glycogen phosphorylase kinase inactivating it
75 to 90 - cloverleaf
Mediates chylomicron secretion

5. What is mosaicism and give an example
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)
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
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Y shaped region along the DNA template where leading nad lagging strands are synthesized

6. What does DNA poly I do?
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
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
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
HVA

7. What converts tyrosine to DOPA
Tryosine hydroxylase
Phenylethamolamine N methyl transferase
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration

8. In eukaryotes - What does RNA poly III make
TRNA
Fed
Locus heterogeneity - ocular albinism is x- linked recessive
HMP shunt

9. Milder form of type I with nl blood lactate levels - dz and enzyme

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10. In eukaryotes - What does RNA poly I make
Cre - lox system
5' of the incoming nucleotide
Disorder of aromatic amino acid metabolism
RRNA

11. caf
Intermediate filaments
Neurofibromatosis type 1 (von Recklinghausens disease)
HMG- CoA (HMG- CoA to mevalonate
Thymic - parathyroid and cardiac

12. What happens in vit D excess
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
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent

13. trinucleotide repeat fo myotonic dystrophy
30 - glycerol -3- phosphate shuttle
CTG
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins

14. What is the energy source in the fed state right after a meal
Glycolysis and aerobic respiration
ATP
AR
Binds 50S - blocking translocation

15. Which anticancer drugs work on microtubules
APC on chromosome 5
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Abnormal protein folding - degradation before reaching cell surface
Vincritsine/vinblastine

16. What does DNA poly III do?

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17. What is a frame shift
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
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
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
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein

18. What is the active form of vit D
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Phenytoin - MTX - and sulfonamides
1 -25 OH2 D3 = calcitriol
Polyneuritis - symmetrical muscle wasting

19. What is uniparental disomy
Cri du chat
Disease
Core proteins
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent

20. What is the longest time of RNA and shortest
Neuralgia
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
MRNA - tRNA
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase

21. Name 5 drugs that interfere with nucleotide synthesis
Neural tube
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Nine
2 -4 DNP - aspirin

22. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
RER
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Cri du chat
Glucose -6 phosphate

23. What does GFAP stain for
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Lysine and arginine
Neuralgia
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA

24. A small proportion of Down syndrome is due to What two genetic events
Glucose - 2Pi - 2ADP - 2NAD+
Robertsonian translocation and mosaicism
Vit K antagonist
Dec methionine - inc cystiene - inc B12/folate

25. What substance in egg whites binds biotin
Degradation of TG remaining in IDL
Avidin
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia

26. What does desmin stain for
Assistance of upper extremities to stand up
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Muscle
Fibrofatty replacement of muscle - cardiac myopathy

27. What is the RDE of gluconeogenesis
RRNA
Achondroplasia
Ketone - methyl
Fructose 1 -6 bisphosphate

28. cytoskeletal elements associated with vimenentin - desmin - cytokeratin - glial fibrillary acid protiens (GFAP) - neurofilaments
Glucose -6 phosphate
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Intermediate filaments
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

29. What is variable expression and What is an example
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Ketone - methyl

30. NADPH are used In what 4 things
Antibiotic use or excessive ingestion of raw eggs
Degradation of TG stored in adipocytes
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)

31. What bone disorder has x linked dominant inheritance
Methionine encode by only 1 codon (AUG)
Alpha and beta tubulin - dimers have two GTP bound
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Orotic acid phosphoribosyltransferase or orotidine 5'- phosphate decarboxylase

32. What are the symptoms of vit A excess
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
32 - malate aspartate shuttle
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
In ER - glucose 6- P to glucose

33. What is the RDE of de novo purine synthesis
Degredation of TG circulating in chylomicrons and VLDLs
Neuralgia
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Glutamine PRPP amidotransferase

34. What polar group does guanine have - and what non polar group does thymine have
Pyruvate to oxaloacetate (3C to 4C)
BOne
Ketone - methyl
UDP glucose pyrophosphorylase

35. What does osteogenesis imperfecta causes and why
Breaks down acyl - coa to acetyl coa groups in mito
CG- 3 > AT-2 - More CG content - melting point goes 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
Schilling test

36. What does vit B3 def result in
Lariat shape in order and remove intron precisely and join 2 exons
Polyneuritis - symmetrical muscle wasting
Leu - lys
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia

37. What is a nonsense mutation
Deamination
ATP
Change resulting in early stop codon
Base + ribose + phosphate (3' -5') phosphodiester bond

38. progressive neurodegeneration - hepatosplenomegaly - cherry red spot on macula - foam cells
Neimann - pick - sphingomyelinase - sphingomyelin - AR
Actin and myosin
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
MRNA

39. What does PURe As Gold and CUT The Py stand for
Cytosol
Supply sufficient glucose to brain and RBCs and to preserve protein
Purines= A - G pyrimidine = C - T (U)
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

40. Who typically has lactase def
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
Williams syndrome
African Americans and Asians
Liver and leafy veggies

41. In prokaryotes - What does makes the different types of RNA
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
Poly A polymerase - signal is AAUAA
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
1 kind with multiple subunits

42. What happens with wet beriberi
Type II
High output cardiac failure - dilated cardiomyopathy - edema
Activates LCAT
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR

43. What are the only purely ketogenic amino acids
Lysine and leucine
Mcardle's - skeletal muscle glycogen posphorylase
PFK - rate limiting enzyme
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol

44. characterize mitochondrial inheritance
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
The triphosphate bond
Inc dicarboxylic acids - dec in glucose and ketones
Transmitted only through mother - all offspring of affected females may show signs of disease

45. In what direction are DNA and RNA synthesized

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46. What are the purely ketogenic amino acids
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Four
Leu - lys
B6

47. What is the name is fxn of vit B3
Fabrys - alpha galactosidase A - ceramide trihexoside - XR
P2 +2pq+ = 1
Foliage - small reserve in liver - eat green leaves
Niacin - constituent of NAD and NADP - derived from tryptophan

48. What happens to glycogen in the liver
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
NF2 on chromosome 22
Flagella - cilia - mitotic spindles

49. What does lactase deficiency cause
Loss of brush border enzyme causing bloating - cramps - osmotic diarrhea
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Same AA - often base change in 3rd position of codon (tRNA wobble)

50. What does fomepizole do
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 EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Glucose -6 phosphate
Rotenone - CN- - antimycin A - CO