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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. How doe NADH electrons from glycolysis and the TCA cycle enter the mitochondiria
Liver - ovaries - seminal vesicles
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
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle

2. What substance inside the cell reduces glutatione
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
NADPH
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
Activates LCAT

3. What causes Down syndrome
Epithelial cells
Degredation of TG circulating in chylomicrons and VLDLs
Polycystic liver disease - berry aneurysm - mitral valve prolapse
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21

4. How do odd chain fatty acids participate in gluconeogenesis
ATP
Glycogen phosphorylase
Via 1 proprionyl - CoA which can enter the TCA as succinyl - CoA and undergo gluconeogenesis
Hereditary defect of renal tubular amino acid transporter for cystein - ornithine - lysine and arginine in PCT

5. What does beta oxidation do and Where does it occur
Breaks down acyl - coa to acetyl coa groups in mito
Proline and lysine - vit C
II - VII - IX - X (1972) protein C and S
Absence of galactose 1 phosphate uridyltransferase - accumulation of toxic substances leads to failure to thrive - jaundice - hepatomegaly - infantile cataracts - mental retardation

6. What is the energy source after day 3 of starvation
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
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Niacin - constituent of NAD and NADP - derived from tryptophan
HMG- CoA (HMG- CoA to mevalonate

7. What does Ehlers Danlos cause and why
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Paclitaxel
Must be both activated and inactivated for cell cycle to progress
Anabolic processes as a supply of reducing equivalents

8. Give an example of a mitochondrial inherited disease
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
Lebers hereditary optic neuropathy - degeneration of retinal ganglion cells and axons - leads to acute loss of central vision. Mitochondrial myopathies
DTMP
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR

9. What is proteasomal degredation
Accelearted muscle breakdown
Attachment of ubiquitin to defective proteins tag them for breakdown
PMNs
Skin

10. What is the exception to genetic redundancy
Debranching enzyme
Covalent cross - linking by lysyl oxidase to make collagen fibrils
NADPH
Methionine encode by only 1 codon (AUG)

11. What is axonemal dynein
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Basement membrane or basal lamina
Phosphofructokinase 1
Oxidative is irreversible

12. What are the blood glucose levels maintained by for days 1-3
Locus heterogeneity - ocular albinism is x- linked recessive
Wrinkles and acne
Type II
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)

13. 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
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
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
Prevent strands from reannealing
Alkaptonuria - may have debiliating arthralgias

14. What is a silent mutation
Von gierkes - glucose 6 phosphatase
Same AA - often base change in 3rd position of codon (tRNA wobble)
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Eu - methionine - pro - formyl - methionine

15. What is the activated carrier for methyl groups
SAM
Kidney - ears - eyes
30 - 50 - 70
Mitochondria

16. What happens in vit D def
Rickets in kids - bending bones - osteomalacia in adults - hypocalcemia tetany - breast milk has dec vit D (supplement in dark skinned patients)
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
APC on chromosome 5
Breaks down acyl - coa to acetyl coa groups in mito

17. What components come together to make S- adenosyl methionine
Chronic granulomatous disease - no respiatory burst - no formatino of ROS
Assistance of upper extremities to stand up
ATP and methionine
Initiate chains

18. What does a decrease in decrease in NADPH lead to and why
IMP precursor
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)
Catabolic processes to carry reducing equivalents away as NADH
Poor defense from oxidizing agents - fava beans - sulfonamides - primaquine - antituberclosis drugs leadig to hemolytic anemia.

19. What does DNA poly I do?
Prokaryotic only - degrades RNA primer and fills in the gap with DNA
Krabbes - galactocerebrosidase - galactocerebroside - AR
Karyotyping
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex

20. delivers hepatic TGs to peripheral tissue - secreted by liver
Anchor muscle fibers - primarily in skeletal and cardiac muscle
RNA
VLDL
O- oligosaccharaides

21. Who typically has lactase def
Essential for the activity of over 100+ enzymes - important in the formatio of zinc fingers -
Mutated dystrophin gene - less severe - adolescence
African Americans and Asians
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria

22. bilateral acoustic schwannomas - juvenile cataracts
NF2 on chromosome 22
CAG - 4
Galactitol - galactose appears in blood and urine - can cause infantile cataracta - AR
Conversion of NE to epi

23. The golgi apparatus fxns as a distribution center between what organelles in the cell and What does it process
Achondroplasia
For proteins and lipids from ER to plasma membrane - lysosomes and secretory vesicles
UDP glucose pyrophosphorylase
High output cardiac failure - dilated cardiomyopathy - edema

24. What are the products for glycolysis
Transmitted through both parents - affected mother may have affected children - affected father will have affected children
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Robertsonian translocation and mosaicism
EtOH dehydrogenase and acetaldehyde dehydrogenase

25. What is anticipation and give an example
X- linked recessive
Inc glucagon - inc cAMP - inc PKA
Severity of disease worsens or age of onset of disease is earlier in succeeding generations - huntingtons
Post to neg

26. What is the amino acid precursor for porphyrin and heme
Oral uridine administration
Antigen - antibody reactivity - can look for antigen or antibody in patients blood
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
Glycine

27. Describe robertsonian translocation
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Huntingtons
Nonreciprocal chromosomal translocation that commonly involves chromosome pairs 13 - 14 - 15 - 21 - 22
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects

28. What is imprinting and give an example

29. What are ketone bodies made from - where are they metabolized and how are they excreted
NADPH
Hydroxyurea - inhibits ribonucleotide reductase - 6 MP - blocks de novo purine synthesis - 5 FU inhibits thymidilate synthase - MTX - inhibits DHFR - Trimethroprin inhibits bacterial DHFR
9+2 arrangement of microtubules
HMG- CoA - brain to 2 molecules of acetyl - Coa - excreted in urine

30. What clotting factors require vit K
Acetly- CoA - CO2 - NADH
II - VII - IX - X (1972) protein C and S
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Eu - methionine - pro - formyl - methionine

31. What does the golgi apparatus do on asparagine
Assistance of upper extremities to stand up
Modifies N- oligosaccharides
Q -
SAM

32. Which cells are rich in smooth ER
Supply sufficient glucose to brain and RBCs and to preserve protein
Reads usual codon but inserts wrong AA
Liver hepatocytes and steroid producing cells of the adrenal cortex
Initiate chains

33. What does apoA 1 do
Achondroplasia
More than 1 codon may code for the same amino acid
Activates LCAT
Metanephrine

34. What is heteroplasmy
Presence of both nl and mutated mtDNA resulting in mitochondrial inherited disease
SAM
Flank pain - hematuria - HTN - progressive renal failure
Dopa decarboxylase

35. What happens in folate def
Macrocytic - megaloblastic anemia - no neurologic sx - most common vit def in the US - seen in EtOH and pregs
Trisomy 13 - severe mental retardation - rocker bottom feet - micophthlamia - microcephaly - cleft lip/palate - holoprosencephaly - polydactyly - congenital heart disease - death usually within the first year
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Liver - ovaries - seminal vesicles

36. what happens in acyl coa dehyrdogenase def
Inc dicarboxylic acids - dec in glucose and ketones
Phenylethamolamine N methyl transferase
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
Deamination

37. What is the structure of elastin
Citrate - acetyl coa from mito to cyto
Tropoelastin with fibrillin scafolding
IDL
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets

38. In eukaryotes - What does RNA poly II make
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
MRNA
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
Malate - aspartate shuttle or the glycerol 3 phosphate shuttle

39. congenital microdeletion of short arm of chromosome 5 with microcephaly - moderate to severe mental retardation - high pitched crying/meying - epicanthal folds - cardiac abnl
ATP hyrdolysis couple to energetically unfavorable rxns
Anabolic processes like steroid and fatty acid synthesis - respiratory burst - P-450 - glutathione reductase
Cri du chat
Cyclin dependent kinases;constitutive and inactive

40. How do glucagon/epi lead to glycogenolysis
Glycine
Adenylyl cycle - inc cAMP - inc PKA - glycogen phosphorylase kinase activated - glycogen phosphoylase active - glycolysis
4 under the floor
Malonyl coa

41. What makes up a nucleotide

42. What is the defect in II A familial hypercholesterolemia
Paclitaxel
Backup of substrate (pyruvate and alanine) resulting in lactic acidosis - congenital or acquired from thiamine def in EtOH - neuro defects
CO2 + NH4 needs carbamoyl phosphate synthase I - in the mitochondria
AD absent of dec LDL receptors causes accelerated atherosclerosis - achilles xanthomas and corneal arcus - increase LDL and elecated cholesterol

43. What enzyme esterifies 2/3 of plasma cholesterol
LCAT (lecithin cholesterol acyltransferase)
Ribulose 5P to ribose 5P - G3P and F6P - transketolase and B1
In cytosol - oxaloacetate to phosphenolpyruvate - requires GTP
Riboflavin - cofactor in oxidation and reduction (FAD and FMN are derived from riboflavin)

44. What is the rate limiting enzyme in cholesterol synthesis
HMG- CoA (HMG- CoA to mevalonate
30 - 50 - 70
Nonsense > missense > silent
By inhibiting formation of the initiation complex and cause misreading of mRNA

45. Which end of the tRNA is the amino acid bound to...

46. What are the findings with homocystinuria and What amino acid is needs to be supplemented
Phosphorylation excess glucose to sequester it - liver becomes blood glucose buffer
Homocystein in ruine - mental retardation - osteoporosis - tall stature - kyphosis - lens subluxation and atherosclerosis leading to stroke and MI - cysteine
N to C
Disease

47. What is the most abundant protein in the body
P+q = 1
Collagen
Autosomal recessive diseases
Post to neg

48. What happens at the smooth ER
Dec AFP - inc betahCGH - dec estradiol - inc inhibin - inc nuchal translucency on US
Site of steroid synthesis and detoxification of drugs and poisons
Glutamine PRPP amidotransferase
Breaks down acyl - coa to acetyl coa groups in mito

49. What activates the pyruvate dehydrogenase complex
Provide a source of NADPH from an abundantly available glucose 6P - create ribose for nucleotide synthesis and glycolytic intermediates
Blood - bone marrown - amniotic fluid - placental tissue
Neural tube
Exercise: inc NAD/NADH - inc ADP - inc Ca

50. What happens in a B12 def
Macrocytic - megaloblastic anemia - hypersegmented PMNs - neurologic symptoms - (parasthesias - subacute combined degeneration) due to abnl myelin - prolonged becomes irreversible
Grows slowly - collapses quickly
Glycine
Acetoacetate and beta hydroxybutyrate