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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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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. In which direction is protein synthesized
No - its non homologous
Essential fructosuria - fructokinase AR
N to C
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact

2. How do tetracyclines work
Phosphofructokinase 1
Bind 30s subunit preventing attachment of aminoacyl - tRNA
One
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

3. What is the Name and fxn of vit B12
Glutamine PRPP amidotransferase
Neurons
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Alpha1 antitrypsin

4. Where is vit A found in the diet
Diphyllobothrium latum
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
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
Liver and leafy veggies

5. What does aminoacyl tRNA synthetase do the AA before and after it binds to tRNA - and what happens if it's the wrong the match
BOne
Scrutinizes - hydrolyzes the bond
Arg - lys - his - arg is most basic - has has no charge at body pH
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

6. In a 1000 meter run - Where does energy come from
Oxidative is irreversible
Muscle
Hypoxanthine to xanthing and xanthine to uric acid
Same as sprint + OXPHOS

7. What does apoE do
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.
Kidney - ears - eyes
Mediates extra remnant take up
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine

8. Which RNA poly opens DNA at promotor site
The triphosphate bond
RRNA
RNA poly II
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints

9. What tissue samples are used for karyotyping
Glycogen and FFA oxidation; glucose conserved for final sprinting
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
P+q = 1
Blood - bone marrown - amniotic fluid - placental tissue

10. What enzyme esterifies 2/3 of plasma cholesterol
LCAT (lecithin cholesterol acyltransferase)
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Not all individuals with a mutant genotype show the mutant phenotype

11. What is the defectin IV - hypertriglyceridemia
Mutated dystrophin gene - less severe - adolescence
FAP
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
Alpha - ketoglutarate dehydrogenase complex

12. What enzyme def can cause emphysema
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Alpha1 antitrypsin
Acetyl - CoA carboxylase (ACC)

13. What form of amino acids are found in proteins
L form
Oxidative and nonoxidative - no ATP produced or used
Inhibit DNA gyrase specific for prokaryotic topoisomerase
Liver hepatocytes and steroid producing cells of the adrenal cortex

14. What does a phosphatase do
Removes phosphate group from substrate
CAG - 4
THFs
Acetyl - CoA carboxylase (ACC)

15. Type III collagen
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Chylomicrons
Liver - also in kidney and gut epithelium
Robertsonian translocation and mosaicism

16. What does the ELISA test for
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Dec methionine - inc cystiene - inc B12/folate
ATP - citrate

17. What bone disorder has x linked dominant inheritance
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
Poly A polymerase - signal is AAUAA
SnRNPs
Alpha1 antitrypsin

18. What is the function of folic acid
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
SnRNPs and other proteins
Octamer = 2 sets of H2A - H2B - H3 - H4 - tie =H1
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR

19. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
FAP
B48 - AIV - CII - E
MRNA - tRNA
Glucose -6 phosphate

20. What is the active form of vit D
Isocitrate dehydrogenase
Nine
1 -25 OH2 D3 = calcitriol
Inhibits the Na/K pump by binding the K side

21. Inhibition of thymidilate synthase and and DHFR lead to decrease In what substance
D2 = ergocalciferol - ingested from plants D3 = cholecalciferol - ingested from milk - formed in sun exposed skin
Mitochondria
Liver hepatocytes and steroid producing cells of the adrenal cortex
DTMP

22. congenital deficiency of homogentisic acid oxidase in the degradative pathway of tyrosine to fumarate leading to dark connective tissue - brown pigmented sclera - urine turns black on standing - dz and worst complication
Alkaptonuria - may have debiliating arthralgias
Breaks down acyl - coa to acetyl coa groups in mito
Heme synthesis - urea cycle and gluconeogenesis - HUGs take two
Inhibits RNA polymerase II - found in death cap mushrooms

23. What is the breakdown product of epi
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Inc fragility of RBC - hemolytic anemia - muscle weakness - posterior column and spinocerebellar tract demyelination
Metanephrine
Liver hepatocytes and steroid producing cells of the adrenal cortex

24. What neuroanatomical strutures are injured in wernicke - korsakoff
Fed
Epithelial cells
Medial dorsal nucleus of thalamus - mamillary bodies
No - its non homologous

25. What drugs can cause folate def
Phenytoin - MTX - and sulfonamides
Mutations at different loci can produce the same phenotype - marfans - MEN 2B - homocystinuria; all cause marfinoid habitus - also albinism
FMR1 gene - methylation - associated with chromosomal breakage
F16BP

26. What is the TX for pyruvate dehydrogenase deficiency
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
HDL
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome

27. What causes Down syndrome
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Alpha1 antitrypsin
NF2 on chromosome 22

28. What is incomplete penetrence and give an example
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Not all individuals with a mutant genotype show the mutant phenotype
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells

29. What enzyme adds Cl - to the H202 to makes bleach
After citruline
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Myeloperoxidase
CGG

30. What is the TX for PKU
Pyruvate to oxaloacetate (3C to 4C)
Carnitine shuttle - acyl - coa from cyto to mito
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
Phenytoin - MTX - and sulfonamides

31. What happens in carnitine def
Superoxide dismutase
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Methionine encode by only 1 codon (AUG)
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia

32. What two pathways is carbomoyl phosphate involved in - and what enzyme deficiency leads to a build of carbamoyl phosphate leading to what element in pyrimidine synthesis
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
APKD1 on chromosome 16
Cytosol
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

33. What is the treatment for orotic aciduria
Oral uridine administration
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Base + ribose
Orotate precursor - with PRPP added later

34. What tissues have both enzymes of sorbitol metabolism
Creat a nick in the helix to relieave supercoils created during replication
Alpha 1 -6 and alpha 1 -4
Liver - ovaries - seminal vesicles
Glutamine PRPP amidotransferase

35. What happens in the first stage of collagen synthesis - and Where does it happen
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
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
UGA - UAA and UAG

36. In which state is PFK-2 active
RNA
Fed
Differences in phenotype depend on whether the mutation is of maternal or paternal origin - prader - willi and angelman's syndrome
Alanine

37. spheroid RBCs due to spectrin or ankyrin defect - hemolytic anemia - inc MHCH - splenectomy is curative
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
Protective against malaria
Polyneuritis - symmetrical muscle wasting
Hereditary spherocytosis

38. What does universal genetic code refer to and What are some exception
Constitutive - random insertion of gene into mouse genome and conditional - targeted insertion or deletion of gene through homologous recombination with mouse gene
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
NADH - NADPH - FADH2

39. Of the four possible fates for pyruvate - which one can replenish TCA cycle or be used in gluconeogenesis
Catabolic processes to carry reducing equivalents away as NADH
Muscle
Oxalacetate
Unmethylated - newly synthesized - HNPCC

40. What enzyme converts phenylalanine to tyrosin
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
The triphosphate bond
Phenylalanine hydroxylase
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

41. What does a kinase do
Uses ATP to add high energy phophate group onto substrate
HMG- CoA reductase
Fructose via sorbitol dehydrogenase - inc sorbitol leading to osmotic damage as in cataracts - retinopathy - peripheral neuropathy as in diabetes
Inhibits acetaldehyde dehydrogenase and contributes to hangover symptoms

42. What polar group does guanine have - and what non polar group does thymine have
Heterochromatin = HighlyCondensed
2 rings
Ketone - methyl
HMG- CoA reductase

43. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
CFTR gene - 7 - Phe 508
Tryosine hydroxylase
Inherited lysosomal storage disorder; failure of addition of mannose 6 phosphate to lysosomal proteins - enzymes secreted outside of cell instead of lysosomes
Hepatic glycogenolysis >> hepatic gluconeogenesis > adipose release of FFA

44. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
Cri du chat
Schwann cells - lens - retina - kidneys
Neurofibromatosis type 1 (von Recklinghausens disease)
Degredation of dietary TG in small intestine

45. What substance accumulates in galactokinase def and What is the clinical picture
Protein kinase A
Stored ATP - creatine phosphate - anaerobic glycolysis
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Flank pain - hematuria - HTN - progressive renal failure

46. What happens in hyperammonemia
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
DsRNA promotes degradation of target mRNA knocking down gene expression
Purines= A - G pyrimidine = C - T (U)
Transfers methyl units

47. What is the Name and fxn of vit B5
Activates LCAT
Fibroblast
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
CFTR gene - 7 - Phe 508

48. bilateral - massive enlargement of of kidneys due to multiple large cysts
Actin and myosin
TRNA
Dec phenylalanine (contained in aspartame - Nutrasweet) inc tyrosine in diet
ADPKD

49. How do cardia glycosides work
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Alpha 1 -4 glucosidase
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility

50. What is the amino acid precursor for porphyrin and heme
Glycine
Alpha1 antitrypsin
Cytosol
IMP precursor