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Test your basic knowledge |
Biochemistry
Start Test
Study First
Subjects
:
health-sciences
,
science
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 does beta oxidation do and Where does it occur
OTC has hyperammonemia - orotic aciduira does not
SAM
Cytosol - F 1 -6 BP to fructose 6 Phosphate
Breaks down acyl - coa to acetyl coa groups in mito
2. In which direction is protein synthesized
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Cri du chat
AR disorder characterized by defective neutral amino acid transporte on renal and intestinal epith cells
N to C
3. Which part of the DNA binds RNA polymerase and multiple other TFs upstream from gene locus
Read from a fixed starting point as a continuous sequence of bases
Promotor - TATA box - and CAAT box - AT rich
Elastase - inhibited by alpha1 antitrypsin
Leu - lys
4. What are the water soluble vitamins - which ones are stored
Terminal regions - tropocollagen
Stored ATP - creatine phosphate - anaerobic glycolysis
B(1 - 2 - 3 - 5 - 6 - 12) C - biotin and folate (B12 and folate are stored)
Targets the proteins for lysosome
5. Gene imprinting implies that How many alleles are active at a single locus
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
P+q = 1
One
Mutated dystrophin gene - less severe - adolescence
6. What initiates protein synthesis
ATP and methionine
GTP hydrolysis - initiation factors assemble 40S ribosomal subunit with initiator tRNA and are released with mRNA and ribosomal subunit assemble with the complex
Prevent strands from reannealing
ADEK - dependent on gut (ileum) and pancreas - accumulate in fat and can cause toxicity
7. What happens to oxaloacetate in alcholism
Pseudomonas and s aureus
Faulty collagen synthesis - hyperextensible skin - tendency to bleed - easy bruising - hypermobile joints
Hypoglycemia
Excess NADH shunts oxaloacetate to malate (backwards) stalling the TCA and shunting glucose and FFA to ketone body production
8. What induces pyruvate kinase
F16BP
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
Ca/calmodulin in muscle to coordinate with muscle activity
Many generations - both male and female affected - often pleiotropic - can present clinically after puberty
9. What is maternal PKU
Poly A polymerase - signal is AAUAA
Lack of proper dietary therapy during pregnancy leading to microcephaly - mental retardation growth retardation - congenital heart defects
Covalent cross - linking by lysyl oxidase to make collagen fibrils
Read from a fixed starting point as a continuous sequence of bases
10. What is the energy source for tRNA actication (charging)
ATP
Dopamine beta hydroxylase
AR
NADPH
11. What collagen type is most frequently affected in ehlers danlos and What are common complications
Fibroblast
III - joint dislocation - anuerysms - organ rupture
BOne
Remain in G0 - regenerate from stem cells - neurons - skeletal/cardiac muscle - RBCs
12. In eukaryotes - What does RNA poly I make
Superoxide dismutase
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Hypophophatemia rickets - vit D resistant ricketts - inc wasting of phosphate in proximal tubule - rickets like presentation
RRNA
13. What does inc phenylalanine lead to...
Scrutinizes - hydrolyzes the bond
CGG
Phenylketones in urine
GTP
14. What two amino acids are required druing periods of growth and why
Bone - skin - tendon - dentin - fascia - cornea - late wound repair
Arg and his inc in histones Which bind negatively charged DNA
Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent
Acetly- CoA - CO2 - NADH
15. facial lesions - hypopigmented 'ash leaf spots -' cortical and retinal hamartomas - seizures - mental retardation - renal cysts - renal angiomyolipomas - cardiac rhabdomyomas - inc risk of astrocytomas
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Carbomoyl phosphate synthetase II
Tuberous sclerosis
Not all individuals with a mutant genotype show the mutant phenotype
16. How does patients present with ADPKD
Flank pain - hematuria - HTN - progressive renal failure
Glucose 6P to CO2 - 2NADPH - ribulose 5P - G6PD - rate limiting step
O- oligosaccharaides
Malabsorption (sprue - enteritis) lack of intrinsic factor from pernicious anemia - gastric bypass surgery or absence of terminal ileum as in Crohns
17. What does vit C def cause
Phenylalanine
Scurvy - swollen gums - bruising - hemarthrosis - anemia - poor wound healing - weakened immune response
Proline and glycine (non glycosylated forms)
UGA - UAA and UAG
18. What are the findings in Lesch - Nyhan
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
G6PD
Glycolysis and aerobic respiration
Retardation - self mutilation - aggression - hyperuricemia - gout - choreoathetosis
19. Type IV collagen is an important structural componenet of the BM for which 3 organs
In ER - glucose 6- P to glucose
Kidney - ears - eyes
Sulfation
Phenylalanine hydroxylase
20. 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
CGG
Inc intestinal absorption fo calcium and phosphate - inc bone resorption
Niacin - constituent of NAD and NADP - derived from tryptophan
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
21. Mild Hurlurs + aggressive behavior no corneal clouding
Anabolic processes as a supply of reducing equivalents
Protective against malaria
Dermatitis - enteritis - alopecia - adrenal insuff
Hunters - iduronate sulfatase - heparan sulfate/dermatan sulfate - XR
22. What is the main source of folate
Vit K antagonist
Chylomicrons
Meiotic nondisjunction of homologous chromosomes (associated with advanced maternal age) leading to trisomy 21
Foliage - small reserve in liver - eat green leaves
23. In mismatch repair - which strand is recognized and In what hereditary syndrome is this defective
Pyruvate carboxylase - PEP carboxykinase - fructose 1 -6 biphosphatase - glucose 6 phosphatase
CAG - 4
Proton gradient
Unmethylated - newly synthesized - HNPCC
24. central and peripheral demyelination with ataxia and dementia
2 pyruvate - 2ATP - 2NADH - 2H+ - 2H2O
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
Metachromatic leukodystrophy - arylsulfatase A - cerebroside sulfate AR
Carnitine acyltransferase I
25. What happens in hyperammonemia
Miscarriage - stillbirth - chromosomal imbalance (down - patau)
Fibroblast
NADPH
Depletes alpha - ketoglutarate leading to inhibition of TCA cycle - tremor slurring of speech - somnolence - vomiting - cerebral edema - blurring of vision
26. What two enzymes are involved in EtOH metabolism
EtOH dehydrogenase and acetaldehyde dehydrogenase
Production of a recombinant DNA molecule that is self perpetuating - plasmids - selection - restriction enzyme cleavage - tissue mRNA with reverse transcriptase to make cDNA
Chylomicrons
Neimann - pick - sphingomyelinase - sphingomyelin - AR
27. What does lipoprotein lipase do
Degredation of TG circulating in chylomicrons and VLDLs
Carbomoyl phosphate synthetase II
4 under the floor
Cori's - debranching enzyme alpha 1 -6 glucosidase - gluconeogenesis intact
28. What enzyme catalyzes the rxn from pyrvuate to Acetyl - CoA and what inhibits it
Inc CPK and muscle biopsy
Pyruvate dehydrogenase - ATP - NADH - acetyl - CoA
Phosphofructokinase 1
Griseofulvin
29. What substances are uncouling agents
RRNA
2 -4 DNP - aspirin
Malapsorption syndromes like sprue or CF or mineral oil intake
N- acteylcysteine - cleave disulfide bonds within mucus glycoproteins
30. Which type of chromatin is condensed - transcriptionally inactive - sterically inaccessible?
Heterochromatin = HighlyCondensed
Base + ribose + phosphate (3' -5') phosphodiester bond
Cystic medial necrosis of aorta leading to aortic incompetence and dissecting aortic aneurysms - floppy mitral valve - subluxation of lenses
Q -
31. What enzyme becomes essential in PKU
Neural tube
Tyrosine
Coenzyme A - lipoamide
RER
32. What is the mutation in beckers muscular dystrophy - What is the severity and time of onset
Hereditary spherocytosis
B100
Mutated dystrophin gene - less severe - adolescence
Phenylalanine hydroxylase
33. inc glycogen in muscle but can't break it down - painful muscle cramps - myglobinuria with strenuous exercise - dz and enzyme
34. Where are the secretory proteins made and N- linked oligosaccharide addtions put on proteins
Cre - lox system
Achondroplasia
RER
Enter G1 from G0 when stimulated - hepatocytes and lymphocytes
35. What metabolic rxns occur in the mitochondria
Fatty acid oxidation - acetyl - Coa production - TCA cycle - OXPHOS
3' end (with CCA)
Thymic - parathyroid and cardiac
BOne
36. In what cell is collagen synthesis initiated
Muscle
GTP
Fibroblast
Pyrophosphate (B1 - thiamine - TPP) FAD (B2 - riboflavin) - NAD (B3 - niacin) - CoA (B5 pantothenate) - lipoic acid
37. Which amino acids are elastin rich in
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
Athralgias - fatigue - headaches - skin changes - sore throat - alopecia
Assistance of upper extremities to stand up
Proline and glycine (non glycosylated forms)
38. What metabolic rxns occur in the cytoplasm
Alanine
Cystine kidney stones - cystine staghorn calculi - cystine is made of two cysteines connected by disulfide bond
Chylomicrons
Glycolysis - fatty acid synthesis - HMP shunt - protein synthesis (RER) - steroid synthesis (SER)
39. How is ammonium transported from muscle to the liver for urea cycle
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
Promotor - TATA box - and CAAT box - AT rich
Limit protein diet - benzoate or phenylbutarate (both bind amino acids leading to excretion) can decrease ammonia levels
1- capping on 5' (7- methyguanosine) 2 - polyadenylation on 3' end 3 - splicing out of introns
40. What is NADPH's role inside RBCs
Acetyl - CoA carboxylase (ACC)
Keep glutathione reduced so it can detoxify free radicals and peroxides
Excess ATP - dATP - feeback inhibits ribonucleotide reductase - no DNA synthesis
PFK - rate limiting enzyme
41. Why is G6PD def more common among patients of african decent
Gaucher's - beta glucocerebrosidase - glucocerebrosie - AR
Protective against malaria
Silencers
DNA
42. What does the TCA cycle produce per 1 acetyl CoA
Hurlers syndrome - alpha L iduronidase - heparan sulfate/dermatan sulfate - AR
3 NADH - 1 FADH2 - 2 CO2 - 1 GTP = 12 ATP (x2 per glucose)
Antioxidant - protects RBCs and membrances from free radical damage
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
43. What happens to glycogen in the liver
Methionine encode by only 1 codon (AUG)
Deamination
Stored and undergoes glycogenolysis to maintain blood sugar at appropriate levels
Inability to transport LCFAs into mitochondria results in toxic accumulation causing weakness - hypotonia - hyperketotic hyperglycemia
44. CF - is AR deletion In what gene On what chromosome resulting in a deletion inf what?
Liver - ovaries - seminal vesicles
CAG
CFTR gene - 7 - Phe 508
Inc insulin - dec cAMP - dec PKA
45. What is the initial transcript called and What is the capped and tailed transcript called
Semiconservative - continuous and discontinuous strands (okazaki fragments)
Hereditary hemorrhagic telangiectasia (Osler - Weber - Rendu syndrome)
Initial is heterogenous nuclear RNA - the capped and tailed is called mRNA
More than 1 codon may code for the same amino acid
46. nucleotide repeat for fredreich's ataxia
GAA
LPL def - or altered apoCII - elevated TG and cholesterol - causes pancreatitis - hepatosplenomegaly and eruptive/pruritic xannthomas - no risk of atherosclerosis
Debranching enzyme
Silencers
47. What does the golgi apparatus do on asparagine
Modifies N- oligosaccharides
Carnitine shuttle - acyl - coa from cyto to mito
Microtubules
Reticulin - skin - blood vessels - uterus - fetal tissue - granulation tissue
48. What is axonemal dynein
Nature and severity of phenotype vary from 1 individual to another - NF type 1
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
ATP
Mental retardation - growth retardation - seizures - fair skin - eczema - musty body odor
49. Why can't even chain fatty acids produce new glucose
They yield only acetyl - CoA equivalents
LCAT (lecithin cholesterol acyltransferase)
Removes phosphate group from substrate
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
50. What occurs to oxaloacetate in starvation and DKA
PFK - rate limiting enzyme
Carnitine acyltransferase I
Depleted for gluconeogenesis staling the TCA cycle and shunting glucose and FFA to production of ketone bodies
Carbomoyl phosphate synthetase I