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. In base excision repaire - what recognizes and removes damaged bases and what cuts the DNA to remove the empty sugar
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
Specific glycosylases - AP endonuclease
Nature and severity of phenotype vary from 1 individual to another - NF type 1
Cofactor for LPL

2. What stretch of DNA that alters gene expression by binding of transcription factors
CAG
Fibroblast
Enhancers
Dermatitis - enteritis - alopecia - adrenal insuff

3. What is the result of vit B5 def
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)
Base + ribose + phosphate (3' -5') phosphodiester bond
Convulsions - hyperirritability - peripheral neuropathy - deficiency inducible by INH and oral contraceptives - sideroblastic anemais
1 -25 OH2 D3 = calcitriol

4. What is the smallest mutation a mircoarray can detect
SNP
Leu - lys
Purines= A - G pyrimidine = C - T (U)
Creat a nick in the helix to relieave supercoils created during replication

5. What does the TCA cycle produce per 1 acetyl CoA
LCAT (lecithin cholesterol acyltransferase)
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
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)

6. What does CATCH 22 stand for and What causes is...
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
X- linked recessive
Aberrant 3rd and 4th branchial arches causing 22q11 deletion - cleft palate - abnl facies - thymic dysplasia - cardiac defects - hypocalcemia secondary to parathyroid aplasia
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells

7. What are the blood glucose levels maintained by for days 1-3
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)
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Tyrosine
Marasmus - muscle wasting

8. What is the function and name of vit B6
RER
1 kind with multiple subunits
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
Unwinds DNA template at replcation fork

9. What is anticipation and give an example
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Unmethylated - newly synthesized - HNPCC
Tryptophan excretion in urine and dec absorption from the gut leading to pellagra
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons

10. decreases In what substances can cause PKU
MRNA
Inc CPK and muscle biopsy
Phenylalanine hydroxylase - tetrahydrobiopterin cofactor
Two

11. What is the amino acid precuros for niacin and serotonin/melatonin
Tryptophan
Inc dicarboxylic acids - dec in glucose and ketones
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Arg and his inc in histones Which bind negatively charged DNA

12. Who typically has lactase def
African Americans and Asians
NADH - NADPH - FADH2
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Tyrosine

13. What converts tyrosine to DOPA
Tryosine hydroxylase
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
B48 - AIV - CII - E
Passed to glutamate - then to alanine enters blood - enters liver - coverted to pyruvate and transfers ammonium back to glutamate which gives it to the urea cycle

14. What are the functinos of vitamin A
Antioxidant - constituent of visual pigment - essential for nl differntiation of epithelial cells into specialized tissue (pancreatic cells - mucus secreting cells) used to treat measles
1 ring
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Disease

15. What is the amino acid precursor for catecholamines
Alpha1 antitrypsin
Inc orotic acid in urine - megaloblastic anemia (does not correct with B12 or folate) - failure to thrive
Phenylalanine
L form

16. What enzymes metabolize fatty acids and amino acids
Acetoacetate and beta hydroxybutyrate
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
RER
Same AA - often base change in 3rd position of codon (tRNA wobble)

17. What is the amino acid precursor for histamine
Oxidative and nonoxidative - no ATP produced or used
CarTWOlage
Histidine
Ribos first then deoxyribos with ribonucleotide reductase

18. What does Citrate Is Krebs starting substrate for making oxaloacetate
RRNA
Microarrays
Citrate - isocitrate - alpha ketoglutarate - succinyl - CoA - succinate - fumarate - malate - oxaleoacetate
MRNA - tRNA

19. What is the rate determining enzyme (RDE) of glycolysis
Post to neg
Phosphofructokinase 1
The triphosphate bond
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)

20. What are CDKs
Cyclin dependent kinases;constitutive and inactive
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
B12 and folate
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid

21. How does patients present with ADPKD
Griseofulvin
Poly A polymerase - signal is AAUAA
Flank pain - hematuria - HTN - progressive renal failure
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

22. What 3 amino acids are necessary for purine synthesis
Krabbes - galactocerebrosidase - galactocerebroside - AR
Glucose 6 phosphate dehydrogenase (G6PD)
Glycine - aspartate - glutamine
O- oligosaccharaides

23. What apolipoproteins are on chylomicrons
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
B48 - AIV - CII - E
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Skin

24. What is a nonsense mutation
VMA
Change resulting in early stop codon
Actin and myosin
Lysine and leucine

25. What is regeneration of methionine depedent on...
Site of steroid synthesis and detoxification of drugs and poisons
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
Tryosine hydroxylase
B12 and folate

26. What does a phosphatase do
Liver hepatocytes and steroid producing cells of the adrenal cortex
Genetic code is conserved throughout evolution - except for mito - archaebacteria - mycoplasma - and some yeast
One
Removes phosphate group from substrate

27. How do you diagnose CFTR
N to C
Inc Cl - in sweat
THFs
Alpha - ketoglutarate dehydrogenase complex

28. What causes Down syndrome
Eu - methionine - pro - formyl - methionine
Lungs - large arteries - elastic ligaments - vocal cords - ligamenta flava - stretch.
African Americans and Asians
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

29. What does DNA poly I do?
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
No mutation occuring at the locus - no selection for any genotypes at the locus - completely random mating - no migration
Impaired glucose breakdown leading to ATP depletion; highly affected aerobic tissues like brain and heart affected first
Aldolase B - AR - fructose 1P accumulates causing a dec in availabel phosphate which inhibts glycogenolysis and gluconeogenesis leading to hypoglycemia - cirrhosis - jaundice and vomiting

30. What lab procedure is used to amplify desired fragment of DNA and What are the 3 steps
PCR - denaturation - annealing - elongation
Diphyllobothrium latum
Alanine
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

31. How is ammonium transported from muscle to the liver for urea cycle
Skin
Passed to glutamate - then to alanine enters blood - enters liver - coverted to pyruvate and transfers ammonium back to glutamate which gives it to the urea cycle
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Wrinkles and acne

32. What is Gowers maneuver
B-100 - CII and E
Cofactor for LPL
Neuralgia
Assistance of upper extremities to stand up

33. What is incomplete penetrence and give an example
Alkaptonuria - may have debiliating arthralgias
Not all individuals with a mutant genotype show the mutant phenotype
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses

34. What is the target of the 3' hydroxyl attack
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation
Chylomicrons
Supply sufficient glucose to brain and RBCs and to preserve protein
The triphosphate bond

35. colon becomes covered witih adenomatous polyps after puberty - progresses to colon cancer unless resected
Makes RNA primer on which DNA poly III can initiate replication
FAP
Tall with long extremeties - pectus excavatum - hyperextensive joints - arachnodactyly
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels

36. What is variable expression and What is an example
Grows slowly - collapses quickly
B100 and E
Cheilosis - inflammation of lips - scaling and fissures at the corner of the mouth - corneal vascularization
Nature and severity of phenotype vary from 1 individual to another - NF type 1

37. nucleotide repeat for fragile x
CGG
Glycogen and FFA oxidation; glucose conserved for final sprinting
Hyperlipidemia
Prevent strands from reannealing

38. What liberates glucose from glucose 6 P
Glucose 6 phosphatase
Oxalacetate
HMG- CoA (HMG- CoA to mevalonate
SnRNPs

39. What does pancreatic lipase do
Hepatic overproduction of VLDL causing pancreatitis - elvelated TGs and VLDL
AR
Degredation of dietary TG in small intestine
Proline and glycine (non glycosylated forms)

40. deletion of VHL gene on chromosome 3 leading to hemangioblastomas of retina/cerebellum/medulla bilateral RCC - dz and overexpression product
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Lariat shape in order and remove intron precisely and join 2 exons
Von hippel lindau - 3
RNA

41. How many rings do purines have
Robertsonian translocation and mosaicism
2 rings
Avidin
Catalase positive (catalase neg produce H2O2 the cell can use) like S. aureus or aspergillus

42. What is the fxn of vit E
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
Antioxidant - protects RBCs and membrances from free radical damage
Specific glycosylases - AP endonuclease
Sucrose = glucose + fructose - lactose = glucose + galactose

43. What does arsenic do and What are th results of poisoning
Acetoacetate and beta hydroxybutyrate
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Essential fructosuria - fructokinase AR
Inhibits lipoic acid - vomiting - rice water stools - garlic breath

44. What does beta oxidation do and Where does it occur
Night blindness - dry skin
Breaks down acyl - coa to acetyl coa groups in mito
1 gene had >1 effect on an individuals phenotype - PKU causes many seemingly unrelated symptoms ranging from mental retardation to hair/skin changes
Proton gradient

45. What is the function of biotin
Delayed wound healing - hypogonadism - dec in adult hair - dysguesia - anosmia - may predispose to EtOH cirrhosis
Kidney - ears - eyes
Cofactor of carboxyltion enzymes: pyruvate carboxylase - acetate - CoA carboxylase - and propionyl - CoA carboxylase
The triphosphate bond

46. What is the limiting reagent in EtOH metabolism
Schwann cells - lens - retina - kidneys
NAD+
Removal of N or C termal propeptides from zymogens to generate mature proteins
Alcohol version of glucose - can trap glucose in cell - aldose reductase

47. What inhibits the carnitine shuttle
Glucose 6 phosphatase
Change resulting in misreading of all nucleotides downstream - usually resulting in a truncated nonfxnal protein
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
Malonyl coa

48. What does the golgi do to sugars in proteoglycans and of selected tyrosine on proteins
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
Phenylalanine hydroxylase
Sulfation
CG- 3 > AT-2 - More CG content - melting point goes up

49. What is the activated carrier for 1 carbon units
Isocitrate dehydrogenase
MEN - 2A and 2B with ret gene
Mutated dystrophin gene - less severe - adolescence
THFs

50. Where is PEP carboxykinase found - What does it do - and What does it require
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Orotate precursor - with PRPP added later
CTG