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. What enzyme results in classic galactosemia and What is the clinical
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Enhancers
Von gierkes - glucose 6 phosphatase
Fed

2. What feedback inhibits hexokinase
Glucose -6 phosphate
Schilling test
Tryptophan
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR

3. in a 100 meter sprint Where does energy come from
Stored ATP - creatine phosphate - anaerobic glycolysis
Degradation of TG stored in adipocytes
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Acetoacetate and beta hydroxybutyrate

4. What does a dehydrogenase do
Robertsonian translocation and mosaicism
Oxidizes substrate
PFK - rate limiting enzyme
L form

5. What is the most common urea cycle disorder and What is the mode of inheritance?
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
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Ornithin transcarbamoylase def - x linked recesssive - other urea cycle enzymes defs are autosommal recessive
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine

6. What are the water soluble vitamins - which ones are stored
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Infection - free radicals generated by inflammatory response
Kwashiorkor - small child with swollen belly
Alkaptonuria - may have debiliating arthralgias

7. What is the active form of vit D
Animal products - synthesized only by microorganisms - large reserve pool - mainly in liver
1 -25 OH2 D3 = calcitriol
Males are infertile due to bilateral absence of vas deferens
Histidine

8. What does amino acid catabolsim results in the formation of what?
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Acetyl - CoA carboxylase (ACC)
Common metabolites like pyruvate and acetyl CoA and excess NH4+ converted to urea and exreted
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra

9. Where are cytosolic and organellar proteins made
Free ribosomes
Neonatal hemorrhage with inc PT and PTT - but nl bleeding time - can also occur after prolonged use of broad spectrum Abx
Keep glutathione reduced so it can detoxify free radicals and peroxides
Glycogenolysis to form glucose

10. What are CDKs
Ketone - methyl
Dermatitis - alopecia - enteritis
APKD1 on chromosome 16
Cyclin dependent kinases;constitutive and inactive

11. Mediates reverse cholesterol transport from periphery to liver - acts as respository for apoC an apoE - secreted from both liver and small intestine
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
Terminal regions - tropocollagen
HDL
Removal of N or C termal propeptides from zymogens to generate mature proteins

12. In what direction are DNA and RNA synthesized

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

13. What are the glucogenic/ketogenic amino acids
Foliage - small reserve in liver - eat green leaves
Inc CPK and muscle biopsy
40 - 60 - 80
Ile - phe - thr - trp

14. Wgat substances directly inhibit mitochondrial ATPase - causing an inc in proton gradient - no ATP because pump is stopped
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Oligomycin
Inhibits lipoic acid - vomiting - rice water stools - garlic breath
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly

15. Which amino acids are elastin rich in
Proton gradient
Thymic - parathyroid and cardiac
Proline and glycine (non glycosylated forms)
Wobble

16. What does Ehlers Danlos cause and why
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
ATP
Mental retardation - hyperphagia - obesity - hypogonadism - hypotonia - deletion of normally active paternal allele on chromosome 15
THFs

17. What is the defect in II A familial hypercholesterolemia
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol
Liver hepatocytes and steroid producing cells of the adrenal cortex
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Reads usual codon but inserts wrong AA

18. cytoskeletal elements associated with cilia - flagella - mitotic spindle - neurones and centrioles
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
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Initiate chains
Microtubules

19. What are the mRNA stop codons
Thiamine - in thiamine pyrophosphate a cofactor for pyruvate dehydrogenase (glycolysis) - alpha ketoglutarate dehydrogenase (TCA cycle) - transketolase (HMP shunt) - and branched - chain AA dehydrogenase
Muscle
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
UGA - UAA and UAG

20. What are possilbe presentation for galactokinase def
L form
Phenylalanine hydroxylase
PMNs
Failure to track objects or develop a social smile

21. What are the findings in Lesch - Nyhan
Intermediate filaments
Converted to THF - a coenzyme for one - carbon transfer/methylation reactions - important for synthesis of nitrogenous bases in DNA and RNA
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss

22. How is Lesch Neyhan inherited
X- linked recessive
Seals.
Methionine encode by only 1 codon (AUG)
Dec methionine - inc cystiene - inc B12/folate

23. How does chloramphenicol work
Oxidative and nonoxidative - no ATP produced or used
Pantothenate - essential component of CoA - a cofactor for acyl transfers and fatty acid synthase
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
Inhibits 50S peptidyltransferase

24. What is dominant negative mutation and give an example
Adds an inorganic phosphate onto substrate without using ATP
DNA
Exerts a dominant effect - a heterozygote produces a nonfxnal altered protein that also prevents the normal gene from functioning - mutation of Tx factor its allosteric site - nonfxning mutant can still bind DNA - preventing wild type Tx from binding
Two

25. What are the irreversible enzymes of gluconeogenesis
Phosphofructokinase 1
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
Wobble
Specific glycosylases - AP endonuclease

26. What substances inhibit phosphofructokinase -1
TTP
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
ATP - citrate

27. What are bite cells and when do you see them
After citruline
Glycolysis and aerobic respiration
Elastase - inhibited by alpha1 antitrypsin
Result from phagocytic removal of heinz bodies my macs - G6PD def

28. What is the trinucleotide repeat in fragile X
Acetly- CoA - CO2 - NADH
CGG
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Comlex II

29. Leysh - Nyhan syndrome is a defect in which enzyme and What are the biochemical results
GTP
Paclitaxel
HGPRT - defective purine salvage - excess uric acid production
Poly A polymerase - signal is AAUAA

30. progressive neurodegeneration - developmental delay - cherry red spot on macula - lysosomes with onion skin - NO hepatosplenomegaly
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Protein

31. What is the wernicke - korsakoff clinical picture
Flagella - cilia - mitotic spindles
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
Consesus sequenec of base pairs
Confusion - opthalmoplegia - ataxia - confabulation - personality changes and memory loss

32. Describe the replication fork
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
Lacks glucose 6 phophatase
Y shaped region along the DNA template where leading nad lagging strands are synthesized
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis

33. How many rings do purines have
2 rings
They yield only acetyl - CoA equivalents
AMP - fructose 2 -6 BP
ATP and methionine

34. developmental delay - gargoylism - airway obstruction - corneal clouding - hepatosplenomegaly
Activates LCAT
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Tay- Sachs - hexosaminidase A - GM2 ganglioside - AR
Glycolysis and aerobic respiration

35. What is the longest time of RNA and shortest
MRNA
MRNA - tRNA
1 ring
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase

36. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
DsRNA promotes degradation of target mRNA knocking down gene expression
Glucose 6 phosphate dehydrogenase (G6PD)
Four
Cri du chat

37. What is the TX for pyruvate dehydrogenase deficiency
Inc intake of ketogenic nutrients - high in fact content or inc lysine or leucine
Neg to pos
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus

38. What step begins the urea cycle and What is the enzyme needed - Where does it happen
Cyclin dependent kinases;constitutive and inactive
Protein kinase A
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
Orotate precursor - with PRPP added later

39. Where is pyruvate carboxylase found - What does it do - What does it require amd What activates it
II - VII - IX - X (1972) protein C and S
Debranching enzyme
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
In mitochondria - pyruvate to oxaloacetate - requires biotin - ATP - activated by acetyl coA

40. How do microtubules grow and collapse
SAM
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
Mental retardation - seizures - ataxia - inappropriate laughter - deletion of normally active maternal allele
Grows slowly - collapses quickly

41. What is variable expression and What is an example
Ca/calmodulin in muscle to coordinate with muscle activity
Inc insulin - dec cAMP - dec PKA
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
Nature and severity of phenotype vary from 1 individual to another - NF type 1

42. Severe fasting hypoglycemia - inc glycogen storage in liver - inc blood lactate - hepatomegaly - dz and def enzyme
Von gierkes - glucose 6 phosphatase
Ketone - methyl
Pompe's lysosomal alpha 1 -4 glucosidase (acid maltase) (pompe trashes the pump; heart - liver - muscle)
Fed

43. What is the defect in fructose intolerance and What does it cause
Phosphenolpyruvate to pyruvate catalyzed by pyruvate kinase
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting
NADPH
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production

44. What enzyme converts adenine to AMP
APRT + PRPP
Glossitis - severe = pellagra - diarrhea - dermatitis - dementia
Progressive hreditary nephritis and deafness - associated with occular disturbances - due to abnl type IV collagen - usually x- linked recessive
LCAT (lecithin cholesterol acyltransferase)

45. Where is acetaldehyde located
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
5' to 3'
Mitochondria
Huntingtons

46. What is the exception to genetic redundancy
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Liver and beta cells of pancreas - low affinity - high Km - high capacity - high Vmax - induced by insulin
Skin
Methionine encode by only 1 codon (AUG)

47. What components come together to make S- adenosyl methionine
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
ATP and methionine
1 ring
Conversion of NE to epi

48. What causes Marfan syndrome
Zero
Superoxide dismutase
Glucose to G-6P - hexokinase and fructose -6P to fructose 1 -6 BP phosphofructokinase -1
Defect in fibrillin

49. What is a missense mutation
HDL
Citrate - acetyl coa from mito to cyto
After day 1
Changed AA (convservative - new AA is similar in chemical structure)

50. What are cyclin - CDK complexes
Mental retardation - macro - orchidism - long face with large jaw - large everted ears - autism - and mitral valve prolapse
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
Essential fructosuria - fructokinase AR
Must be both activated and inactivated for cell cycle to progress