Test your basic knowledge |

Biochemistry

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. Which enzyme involved in RNA synthesis does not require a template
FISH
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Poly A polymerase - signal is AAUAA
Active secretion in lungs and GI - reabsorbs in skin

2. What are the mRNA stop codons
UGA - UAA and UAG
Two
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Acetyl - CoA to malonyl - CoA (2C to 3C)

3. Which cells are rich in smooth ER
Glucose 6 phosphate dehydrogenase (G6PD)
Poly A polymerase - signal is AAUAA
Disease
Liver hepatocytes and steroid producing cells of the adrenal cortex

4. Type II cartilage
Q -
CarTWOlage
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Protein kinase A

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

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

6. What is the defect in II A familial hypercholesterolemia
Vit K antagonist
NF2 on chromosome 22
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol

7. What is the RDE of de novo purine synthesis
Glutamine PRPP amidotransferase
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
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
Neuralgia

8. What are possilbe presentation for galactokinase def
Failure to track objects or develop a social smile
Glucose -6 phosphate
Oxidizes substrate
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

9. recurrent pulmonary infxns in CF are due to what organisms
Tryptophan
Pseudomonas and s aureus
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Mitochondria

10. How does abetalipoproteinemia present and What is the defect
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Unwinds DNA template at replcation fork
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 - enteritis - alopecia - adrenal insuff

11. What are cyclins
Isocitrate dehydrogenase
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Result from phagocytic removal of heinz bodies my macs - G6PD def
Regulatory proteins that control cell cycle events; phase specific; activate CDKs

12. What causes Hartnup's disease
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
O- oligosaccharaides
SAM
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

13. What happens in carnitine def
Liver - ovaries - seminal vesicles
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Alanine
Arg and his inc in histones Which bind negatively charged DNA

14. What does hartnups disease cause
Antioxidant - protects RBCs and membrances from free radical damage
Same as sprint + OXPHOS
F16BP
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

15. What causes maple syrup urine disease and What does it lead to...
Particular sequence of DNA where replicatino begins - may be single of multiple
By inhibiting formation of the initiation complex and cause misreading of mRNA
Pseudomonas and s aureus
Dec in alpha ketoacid dehydrogenas leading to blocked degredation of branches amino acids like Ile - Leu - and Val - severe CNS defects mental retardation and death

16. What is the TX for CF and What does it do
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
APRT + PRPP
Glycolysis and aerobic respiration

17. What substances inhibit phosphofructokinase -1
ATP - citrate
NADPH
Inc Cl - in sweat
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1

18. What substances are uncouling agents
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
2 -4 DNP - aspirin
HMG- CoA synthase
Seals.

19. facial lesions - hypopigmented 'ash leaf spots -' cortical and retinal hamartomas - seizures - mental retardation - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas - inc risk of astrocytomas
Flank pain - hematuria - HTN - progressive renal failure
Tuberous sclerosis
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
PFK - rate limiting enzyme

20. What is the RDE of the HMP shunt
Procollagen - triple helix of 3 alpha collagen chains
Glucose 6 phosphate dehydrogenase (G6PD)
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
Ile - phe - thr - trp

21. Do balanced translocations cause abnl phenotype
No
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
Transfers cholesterol from mature HDL to VLDL - IDL and LDL (cholesterol ester transfer protein)
Von hippel lindau - 3

22. What is the complication of cystinuria
Oxidized hemoglobin precipiated within RBCs
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond

23. What does apoCII do
Cofactor for LPL
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
CGG
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

24. What does hepatic TG lipase do
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Degradation of TG remaining in IDL
Microarrays

25. What enzyme adds Cl - to the H202 to makes bleach
Catabolic processes to carry reducing equivalents away as NADH
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Myeloperoxidase
Familial hypercholesterolemia - hyperlipidemia type IIA

26. In which single strand DNA repair mechanism do specific endonucleases release the oligonucTIDE containing bases and DNA poly and ligase fill and reseal - and what disease occures when this is mutated
L form
FMR1 gene - methylation - associated with chromosomal breakage
Nucleotide excision repair - xeroderma pigmentosum; unable to repair thymidine dimers caused by UV light
Transmitted through both parents - affected mother may have affected children - affected father will have affected children

27. cytoskeletal elements associated with cilia - flagella - mitotic spindle - neurones and centrioles
Glucose 6 phosphate dehydrogenase (G6PD)
Site of steroid synthesis and detoxification of drugs and poisons
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Microtubules

28. Infection with what organism can cause B12 def
Diphyllobothrium latum
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Prevent strands from reannealing
5' of the incoming nucleotide

29. What produces NADPH
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
HMP shunt
Mcardle's - skeletal muscle glycogen posphorylase
Glycogenolysis to form glucose

30. What form of amino acids are found in proteins
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
L form
Unmethylated - newly synthesized - HNPCC
DTMP

31. How does ethanol induce hypoglycemia
Inc NADH/NAD ratio in liver - causing diversion of pyruvate to lactate and OAA to malate - inhibiting gluconeogenesis and stimulating fatty acid synthesis. Leads to hypoglycemia and hepatic fatty liver change seen in chronic EtOH users
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Acetyl - CoA

32. For eukaryotes - Where does replication begin?
RER
Glucose - 2Pi - 2ADP - 2NAD+
Consesus sequenec of base pairs
Essential fructosuria - fructokinase AR

33. In the chromatin structure - which histones form the octamer - and which ties the nucleosome beads together in a string?
Protective against malaria
Promotor - TATA box - and CAAT box - AT rich
CAG - 4
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1

34. What does SAM do
Particular sequence of DNA where replicatino begins - may be single of multiple
Transfers methyl units
Must be both activated and inactivated for cell cycle to progress
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR

35. How do glucagon/epi lead to glycogenolysis
VMA
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
P2 +2pq+ = 1
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)

36. What are the symptoms of vit A excess
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
CFTR gene - 7 - Phe 508
Neg to pos
Oxalacetate

37. What is the function of folic acid
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
No - its non homologous
Neuralgia

38. What does Alports syndrome cause and why
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
FMR1 gene - methylation - associated with chromosomal breakage
Karyotyping

39. How is orotic aciduria inherited
AR
Mitochondria
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Achondroplasia

40. Where is vit A found in the diet
Males are infertile due to bilateral absence of vas deferens
Same AA - often base change in 3rd position of codon (tRNA wobble)
Biotin
Liver and leafy veggies

41. What is axonemal dynein
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Neural tube
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
Inhibits RNA polymerase II - found in death cap mushrooms

42. What enzyme turns ROS to H2O2
Superoxide dismutase
Glycine - aspartate - glutamine
Acetly- CoA - CO2 - NADH
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)

43. What is pleiotropy and given an example
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Particular sequence of DNA where replicatino begins - may be single of multiple
Secretion of abnl thick mucus that plugs lungs - pancreas - liver
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations

44. The pyruvate dehydrogenase complex serves In what reaction: products
Acetly- CoA - CO2 - NADH
30 - glycerol -3- phosphate shuttle
Adenosine to inosine
Microarrays

45. What is the pathway in the fed state leading to dec FBPase -2 and inc PFK-2
Mucus secreting globlet cells and antibody secreting plasma cells
Accelearted muscle breakdown
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Inc insulin - dec cAMP - dec PKA

46. What defects characterize velocardiofacial syndrome
Arg - lys - his - arg is most basic - has has no charge at body pH
Hypercalciuria - loss of appetite - stupor - seen in sarcoidosis from activation fo vit D by epithelioid macrophage
Palate - facial and cardiac defects
Not all individuals with a mutant genotype show the mutant phenotype

47. What ribosomes do eukaryotes have
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
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
40 - 60 - 80

48. Why is G6PD def more common among patients of african decent
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Only processed RNA
Protective against malaria
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP

49. What is the activated carrier for aldehyddes
Phenylalanine hydroxylase
TTP
Phenytoin - MTX - and sulfonamides
Proton gradient

50. trinucleotide repeat fo myotonic dystrophy
Tuberous sclerosis
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Oxalacetate
CTG