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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 axonemal dynein
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
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

2. The golgi apparatus fxns as a distribution center between what organelles in the cell and What does it process
SnRNPs
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Fructose 1 -6 bisphosphate
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles

3. I g fat = ? Kcal
Glutamine PRPP amidotransferase
Directly inhibit the Na/K pump which leads to indirect inhibition of Na/Ca exchange - inc calcium inside the cell - inc cardiac contractility
Nine
Exercise: inc NAD/NADH - inc ADP - inc Ca

4. How do glucagon/epi lead to glycogenolysis
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
Karyotyping
Inhibits EtOH dehydrogenase and is an antidote for methanol and ethylene glycol poisoning
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis

5. What is the composition of urea and where do each part derive from
Creat a nick in the helix to relieave supercoils created during replication
Histidine
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
No

6. what findings are associated with marfans
Oxidative is irreversible
HGPRT - defective purine salvage - excess uric acid production
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
EtOH dehydrogenase and acetaldehyde dehydrogenase

7. What is the purpose of the HMP shunt
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
AMP - fructose 2 -6 BP
Nine
Epithelial cells

8. What does amino acid catabolsim results in the formation of what?
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Cobalamin - cofactor of homocysteine and methyltransferase - methylmalonyl CoA mutase
Phosphofructokinase 1
Phenylketones in urine

9. What do neurofilaments stain for
Fibroblast
Neurons
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx

10. What is the prevalence of an X- linked recessive disease in males and in females
Glycolysis and aerobic respiration
UGA - UAA and UAG
MRNA
Q -

11. What are the mRNA stop codons
Four
Blood - bone marrown - amniotic fluid - placental tissue
Schilling test
UGA - UAA and UAG

12. Which type of chromatin is less condensed - transcriptionally active - sterically accesible
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
CarTWOlage
Euchromatin

13. Type I collagen
Particular sequence of DNA where replicatino begins - may be single of multiple
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles

14. How does OTC def present
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
Blood - bone marrown - amniotic fluid - placental tissue
MRNA - tRNA
Consesus sequenec of base pairs

15. In which direction is protein synthesized
Niacin - constituent of NAD and NADP - derived from tryptophan
N to C
Facial flushing
2 rings

16. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Promotor - TATA box - and CAAT box - AT rich
Met - val - arg his
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

17. Which direction does dynein go
ATP
Post to neg
Inhibits the Na/K pump by binding the K side
Wobble

18. facial lesions - hypopigmented 'ash leaf spots -' cortical and retinal hamartomas - seizures - mental retardation - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas - inc risk of astrocytomas
Leu - lys
APKD1 on chromosome 16
Tuberous sclerosis
Nonsense > missense > silent

19. What is a silent mutation
TRNA
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
Same AA - often base change in 3rd position of codon (tRNA wobble)
Proton gradient

20. What is the RDE of fatty acid synthesis
Tropoelastin with fibrillin scafolding
Alpha1 antitrypsin
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
Acetyl - CoA carboxylase (ACC)

21. What happens in folate def
Myeloperoxidase
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
ATP hyrdolysis couple to energetically unfavorable rxns

22. What apolipoproteins are on chylomicrons
Oral uridine administration
Intermediate filaments
25OHD3
B48 - AIV - CII - E

23. What are the characteristics of prader willi syndrome How does it occur
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
APRT + PRPP
Inc CPK and muscle biopsy
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15

24. What are the fat soluble vitamins and What does their absorption depend on...
Alanine
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
Comlex II
Covalent cross - linking by lysyl oxidase to make collagen fibrils

25. What does cytokeratin stain for
ATP and methionine
Epithelial cells
Euchromatin
Malonyl coa (+ biotin= palmitiate - 1 16C fatty acid)

26. How do permanent cells grow and regenerate and What are examples of permanent cells
THFs
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
Tuberous sclerosis
F16BP

27. What is the limiting reagent in EtOH metabolism
Degradation of TG remaining in IDL
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
NAD+

28. Give an example of a mitochondrial inherited disease
Paclitaxel
Supply sufficient glucose to brain and RBCs and to preserve protein
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
Hypoxanthine to xanthing and xanthine to uric acid

29. What are the 3 AR forms of homocystinuria
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
Cystathionine synthase def - dec affinity of cystathionine synthase for pyridoxal phosphate - homocystein methyltransferase def
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Glutamine PRPP amidotransferase

30. Why can't even chain fatty acids produce new glucose
Dec methionine - inc cystiene - inc B12/folate
They yield only acetyl - CoA equivalents
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
APC on chromosome 5

31. How many ATP are produced by anearobic glycolysis per molecule of glucose
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Two
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Orotate precursor - with PRPP added later

32. What is the energy source after day 3 of starvation
Read from a fixed starting point as a continuous sequence of bases
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
Elastase - inhibited by alpha1 antitrypsin
1 ring

33. What are bite cells and when do you see them
G6PD
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
Hypoxanthine to xanthing and xanthine to uric acid
Result from phagocytic removal of heinz bodies my macs - G6PD def

34. How do tetracyclines work
Bind 30s subunit preventing attachment of aminoacyl - tRNA
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Skin

35. depression - progressive dementia - choreiform movements - caudate atrophy and dec levels of GABA and ACH in the brain
Phenylethamolamine N methyl transferase
Ribos first then deoxyribos with ribonucleotide reductase
Huntingtons
Chronic granulomatous disease - no respiatory burst - no formatino of ROS

36. What are the priorities for the body in fasting and starvation
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Glycine
Supply sufficient glucose to brain and RBCs and to preserve protein
Keep glutathione reduced so it can detoxify free radicals and peroxides

37. What does lipoprotein lipase do
NH2-(C=O) - NH2 one NH2 from ammonia the C=O from CO2 - and the other NH2 from aspartate
Not all individuals with a mutant genotype show the mutant phenotype
Degredation of TG circulating in chylomicrons and VLDLs
Glucose - 2Pi - 2ADP - 2NAD+

38. characterize x linked dominant
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Liver - ovaries - seminal vesicles
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1

39. What do def in in enzymes of gluconeogenesis cause
Hypoglycemia
RER - translation of alpha chains - usually Gly-X-Y polypeptide (preprocollagen)
Inhibit DNA gyrase specific for prokaryotic topoisomerase
NAD+

40. elevated LDL due to defective or absent LDL receptor - heterozygotes have cholesterol ~300 - homozygotes ~700
Wrinkles and acne
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Familial hypercholesterolemia - hyperlipidemia type IIA

41. What does the mutation in the gene cause in protein synthesis
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Glycogenolysis to form glucose
Acetyl - CoA
Abnormal protein folding - degradation before reaching cell surface

42. Where is EtOH dehydrogenase located
ATP hyrdolysis couple to energetically unfavorable rxns
Tropoelastin with fibrillin scafolding
Dermatitis - enteritis - alopecia - adrenal insuff
Cytosol

43. What is the RDE of TCA cycle
Lack of tyrosinase (no melanin) AR ordefective tyrosine transporters (less tyrosine) - can results in lack of migration of NC cells
Ribose 5- P to PRPP
Isocitrate dehydrogenase
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

44. Delivers dietary TGs to peripheral tissues - delivers cholesterol to liver in the form of remnants - mostly depleted of TGs - secreted by intestinal epith cells
Leu - lys
Chylomicrons
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
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

45. What substance inside the cell reduces glutatione
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
HDL
NADPH
GTP

46. What are the symptoms of vit A excess
Elastase - inhibited by alpha1 antitrypsin
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Conversion of NE to epi
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia

47. How do stable (quiescent) cells grow and regenerate and What are examples
CFTR gene - 7 - Phe 508
PCR - denaturation - annealing - elongation
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes

48. What stretch of DNA that alters gene expression by binding of transcription factors
Rb and p53
Chylomicrons
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Enhancers

49. Which step in the de novo purine and pyrimidine synthesis pathway requires just aspartate
Tendency for certain alleles at 2 linked loci to occur together more often than expected by chance - varies is different populations
Phosphofructokinase 1
Ubiquitous - low Km - high affinity - low capacity low Vmax - uninduced by insulin
Orotic acid to UMP

50. Where is glucose 6 phosphatase found and What does it do
Propionyl - CoA to methylmalonyl - CoA (3C to 4C)
Glucose -6 phosphate
In ER - glucose 6- P to glucose
SAM