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Biochemistry Flashcards

1
Q

Chromatin Structure

A

H1 bind to nucleosome and to linker DNA –> stabilize chromatin fiber.
(-) phosphate
(+) lysine and arginine

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2
Q

Heterochromatin

A

Condensed, transcriptionally inactive
increased methylation
decreased acetylation
ex. Barr bodies

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3
Q

Euchromatin

A

less condensed, transcriptionally active

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4
Q

Histone Methylation

A

reversible transcription suppression usually

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5
Q

Histone Acetylation

A

remove histone (+) charge –> relaxed DNA coiling –> increase transription

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6
Q

Histone deactylation

A

remove acetyl groups –> tighten DNA –> decrease transcription

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7
Q

Deamination reactions

A

Cytosine –> uracil
Adenine –> hypoxanthine
Guanine –> xanthine
5- methylcytosine –> thymine

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8
Q

Amino acids in purine synthesis

A

glycine
aspartate
glutamine

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9
Q

Pyrimidine synthesis drugs

A

Leflunomide (inhibit dihydroorotate dehydrogenase)

5-FU and capecitabine (inhibit thymidine synthase via increase 5F-dUMP

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10
Q

Purine Synthesis drugs

A

6-MP and azathioprine (inhibit de novo purine synthesis)

Mycophenolate and ribavirin (inhibit inosine monophosphate dehydrogenase)

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11
Q

Purine and Pyrimidine synthesis drugs

A

Hydroxyurea (inhibit ribonucleotide reductase)

methotrexate (human), trimethoprim (bacteria), pyrimethamine(protozoa) (inhibit DHR reductase)

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12
Q

Adenosine deaminase deficiency

A

degrade adenosine and deoxyadenosine
decreased ADA –> increased dATP –> decrease ribonucleotide reductase activity –> lymphotoxicity
AR SCID

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13
Q

Lesch Nyhan Syndrome

A

X linked Recessive
absent HGPRT (convert hypoxanthine to IMP and guanine to GMP) excess uric acid production and de novo purine synthesis.
Disability self mutilation, aggression, hyperuricemia, gout, dystonia
T(x) allopurinol or febuxstat

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14
Q

Origin of replication

A

TATA box

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15
Q

Helicase

A

unwind DNA

Deficient: BLOOM syndrome (BLM gene mut.)

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16
Q

DNA topoisomerase

A

create single or double stranded break in helix to add or remove supercoils
Eukaryotes- irinotecan inhibit TOP 1, etoposide inhibit TOP 2
Prokaryotes- fluoroquinolones inhibit TOP 2 and 4

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17
Q

DNA polymerase 3

A

Prokaryotes only. DNA poly 3 is 5 –> 3 synthesis. Drugs blocking DNA replication have a modified 3’OH –> chain termination.

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18
Q

DNA polymerase 1

A

Prokaryotes only. excise RNA primer in 5 –>3 direction

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19
Q

Telomerase

A

Eukaryotes only. Reverse transcriptase thats adds TTAGGG to 3’ end. Dysregulation –> cancer

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20
Q

Lac operon

A

E.coli
glucose is absent and lactose is present –> activation for lactose metabolism.
low glucose –> increase adenylate cyclase –> increase cAMP –> activate CAP –> increase transcription
High lactose –> unbinds repressor protein –> increase transcription

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21
Q

Nucleotide excision repair

A

Single Strand
endocuclease cut damaged DNA. DNA pol and ligase fill. G1 phase.
Defect: xeroderma pigmentosum (inability to repair DNA pyrimidine dimers caused by UV) –> dry skin, light sensitivity, skin cancer

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22
Q

Base excision repair

A

Single Strand
Glycosylase removes altered base and creates AP side. Nucleotides removed by AP- endonuclease/lyase. DNA pol and ligase fill gaps.
Spontaneous or toxic deamination

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23
Q

Mismatch repair

A

Single Strand
S phase
Defective: Lynch syndrome (HNPCC)

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24
Q

Nonhomologous End joining

A

Double strand
Brings together 2 ends of DNA fragments. Lost DNA
Defect: Ataxia Telangiectasia

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25
Q

Homologous End Joining

A

Double Strand
2 homologous DNA duplexes. No lost DNA
Defect: BRCA1 and Fanconi anemia

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26
Q

Promoter

A

Site where RNA pol 2 and transcription factors bind to DNA upstream from gene locus. Mutation –> dramatic decrease in gene transcription

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27
Q

Enhancer and Silencer

A

located close to or far from or within gene.

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28
Q

RNA processing

A
  1. 5’ cap (7 methylguanosine)
  2. polyadenylation 3’
  3. splice out introns
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29
Q

Eukaryote RNA pol

A

1- makes rRNA
2- makes mRNA, miRNA, snRNA, open DNA at promoter site.
3- tRNA

a-amanitin (cap mushrooms) inhibit RNA pol 2 –> hepatotoxicity
Actinomycin D- inhibit RNA pol in pro and eukaryotes

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30
Q

Prokaryote RNA pol

A

1 RNA pol makes all RNA

Rifampin inhibit DNA dependent RNA pol in prokaryotes

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31
Q

snRNP defect

A

Spinal Muscular Atrophy (decreased SMN protein) –> congenital degeneration of anterior horns of spinal cord –> symmetric weakness (floppy baby)

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32
Q

tRNA structure

A

CCA on 3’ end carry amino acid
T-arm - tRNA ribosome binding
D- arm- allow detection by aminoacyl tRNA synthetase

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33
Q

tRNA charging

A

aminoacyl tRNA synthetase binds charged tRNA to the codon.

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34
Q

Initiation Protein Synthesis

A
  1. eukaryotic initiation factors identify 5’cap
  2. assemble the 40S ribosomal subunit with the initiatory tRNA
  3. released when the mRNA and the ribosomal 60S subunit assemble with the complex (requires GTP)
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35
Q

Elongation Protein Synthesis

A
  1. Aminoacyl tRNA synthetase binds to A site (require elongation factor and GTP)
  2. rRNA catalyze peptide bond formation, transfers growing polypeptide to amino acid in A site
  3. Ribosome advances 3 nucleotides toward 3’ end of mRNA, moving peptidyl tRNA to P site
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36
Q

Termination Protein Synthesis

A

Eukaryotic release factors recognize the stop codon and halt translation –> completed polypeptide is released from ribosome. (requires GTP)

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37
Q

CDK

A

constitutively expressed but inactive when not bound to cyclin

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38
Q

cyclin

A

regulatory proteins that control cell cycle events; phase specific, activate CDKs

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39
Q

Cycin-CDK

A

phosphorylate other proteins to coordinate cell cycle progression; must be activated and inactivated at appropriate times for cell cycle progress

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40
Q

Tumor suppressors

A

p53 –> induce p21 –> inhibit CDK –> Rb hypophosphorylate (activate) –> inhibit G1S
Mut –> Li Fraumeni
Growth factors bind TK receptors to transition the cell from G1 –> S

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41
Q

Rough ER

A

synthesis of exported proteins and N-linked oligosaccharide addition to lysosomal and other proteins
Nissl bodies- synthesize peptide neurotransmitters for secretion
Free ribosomes- unattached to any membrane are site of synthesis of cytosolic, peroxisomal and mitochondrial proteins

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42
Q

Smooth ER

A

site of steroid synthesis and detox of drugs and poisons. Glucose 6 phosphatase.
Liver, hepatocytes and adrenal cortex and gonads

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43
Q

Golgi

A

distribution center
N oligosaccharides on Asparagine
O oligosaccharides on serine and threonine
Mannose 6 Phosphate to lysosome.

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44
Q

I cell Disease

A

inherited lysosomal storage disease (AR)
Defect in NAP –> failure of golgi to phosphorylate mannose residues –> proteins are secreted extracellularly rather than delivered to golgi. –> coarse facial features, gingival hyperplasia, clouded cornea, restricted joint movement, claw hand, high plasma lysosomal enzymes.
FATAL at childhood

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45
Q

Dysfunctional Signal recognition proteins

A

accumulation of protein in cytosol

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46
Q

Vesicular trafficking proteins

A

COPI: golgi –> golgi –> ER
COPII: golgi forward
Clathrin: golgi–> lysosomes, PM –> endosomes

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47
Q

Peroxisome

A

B oxidation of VLCFA
a oxidation of branched FA
catabolism of amino acids and ethanol
synthesis of cholesterol, bile acids and plasmalogens

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48
Q

Zellweger Syndrome

A

AR
mut PEX (peroxisome biogenesis)
Hypotonia, seizures, hepatomegaly, early death

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49
Q

Refsum Disease

A

AR a oxidation
phytanic acid not metabolized to pristanic acid.
Scaly skin, ataxia, cataracts, shortening of 4th toe, epiphyseal dysplasia
T(x): diet, plasmapheresis.

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50
Q

Adrenoleukodystrophy

A

X linked Recessive B oxidation
ABCD1 mut –> VLCFA buildup in adrenal glands, white matter of brain, testes,
Adrenal gland crisis, coma, death

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51
Q

Microfilaments

A

Muscle contraction, cytokinesis (actin, microvilli)

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52
Q

Intermediate Filaments

A

Maintain cell structure (vimentin, desmin, cytokeratin, lamins, GFAP, neurofilament)

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53
Q

Microtubules

A

Movement and cell division (cilia, mitotic spindle, axonal trafficking, centrioles)
Retrograde (Dyenin)
Anterograde (kinesin)
C. tetani, HSV, polio, rabies use dyenin
Drugs: mebendazole, griseofulvin, colchicine, Vincristine, Paclitaxel

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54
Q

Cilia Structure

A

9 doublet + 2 singlet

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55
Q

Kartagener Syndrome

A

AR
immotile cilia due to dyenin arm defect.
decrease male and female fertility due to immotile sperm and dysfunctional fallopian tube cilia. Increased risk of ectopic pregnancy. Can cause bronchiectasis, recurrent sinusitis, chronic ear infections, conductive hearing loss and situs inversus.
Screening: decreased NO nasal

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56
Q

Na+/K+ ATPase

A

each ATP –> 3 Na+ leave cell, 2K+ enter cell
Ouabin inhibit binding to K+ site
Cardiac glycosides (digoxin) inhibit Na+/K= ATPase –> inhibit Na+/Ca2+ exchange –> increase Ca2+ –> increase cardiac contractility

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57
Q

Type 1 Collagen

A

Bone, Skin, Tendon

Decrease in osteogenesis Imperfecta

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58
Q

Type 2 Collagen

A

Cartilage

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59
Q

Type 3 Collagen

A

Reticulin (blood vessels)

Defect- vascular type ehlers Danlos

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60
Q

Type 4 Collagen

A

Basement Membrane

Defect: alport syndrome and targeted by autoantibodies in Goodpasture syndrome

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61
Q

Collagen Synthesis

A
  1. Synthesis- translation of collagen a chains (1/3 glycine)
  2. Hydroxylation- proline and lysine residues (requires vitamin C)
  3. Glycosylation- a chain hydroxylysine residues and formation of procollagen via hydrogen and disulfide bonds. (defect osteogenesis imperfecta)
  4. Exocytosis into extracellular space
  5. Proteolytic processing- cleave disulfide rich terminal regions of procollagen –> insoluble tropocollagen
  6. cross linking- covalent lysine- hyrdoxylysine –> collagen fibrils (defect: Menkes Disease)
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62
Q

Osteogenesis Imperfecta

A

AD
Defect COL1A1 and COL1A2
Multiple fractures and bone deformities after minimal trauma, blue sclera, tooth abnormalities, conductive hearing loss.

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63
Q

Ehlers Danlos

A

Faulty collagen causing hyperextensible skin, hypermobile joints and tendency to bleed.
Classical: COL5A1/5A2- joint and skin
Vascular- COL3A1- fragile tissues including vessels.

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64
Q

Menkes Disease

A

X linked recessive
impaired copper absorption and transport (ATP7A).
Lower copper levels –> decrease activity of lysyl oxidase –> defective collagen
Brittle, kinky hair, growth retardation, hypotonia, increase risk of cerebral aneurysms

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65
Q

Elastin

A

stretchy protein in skin, lungs, large arteries, elastic ligaments, vocal cords. Rich in nonhydroxylated proline, glycine and lysine.
a1 antitrypsin inhibits breakdown

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66
Q

Marfan Syndrome

A

AD (FBN1 gene mutation on Chromosome 15)
tall with long extremities, pectus carinatum or excavatum. hypermobile joints, long tapering fingers and toes, cystic medial necrosis of aorta, aortic aneurysm, rupture or dissection. mitral valve prolapse. Subluxation of lenses

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67
Q

PCR

A

Amplify DNA

  1. Denature (95C)
  2. Anneal (55C)
  3. Elongate (72C)
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68
Q

rtPCR

A

detect mRNA. uses reverse transcription to create complimentary DNA template.

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69
Q

CRISPR

A

genome editing. guide RNA complimentary to target DNA and Cas9 endonuclease makes break at target site. Break is repaired by NHEJ –> frameshift mutation (knock out)

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70
Q

Southern Blot

A

DNA cleaved and electrophoresis
radiolabeled DNA probe
Film

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71
Q

Northern Blot

A

RNA sample

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72
Q

Western Blot

A

Protein sample

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73
Q

Southwestern Blot

A

DNA binding protein

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74
Q

Flow Cytometry

A

assess size, granularity and protein expression of individual cells in a sample.
Cells tagged with Ab
Workup for hematologic abnormalities

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75
Q

Microarrays

A

nucleic acid on grid. DNA or RNA probe hybridized to the chip and scanner detects the relative amounts of complimentary binding.
profile gene expression levels of thousands of genes simultaneously.
Detect SNPs and CNVs

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76
Q

Enzyme linked immunosorbent assay

A

detect presence of specific Ag or Ab in patient blood sample. Substrate reacts with enzyme –> detectable signal.

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77
Q

Karyotyping

A

Colchicine is added to cell. Chromosomes stained, ordered and numbered according to morphology.
Performed on blood, cone marrow, amniotic fluid or placental tissue.

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78
Q

Fluorescence in sity hybridization

A

Fluorescent DNA/ RNA probe binds to specific gene site of interest on chromosomes.
Specific localization of genes and direct visualization of chromosomal anomalies at molecular level

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79
Q

Molecular cloning

A

Production of recombinant DNA molecule in a bacterial host

80
Q

Cre-Lox

A

inducibly manipulate genes at specific developmental points

81
Q

miRNA

A

naturally produced by the cell as hairpin structures. Block translation and accelerating mRNA degradation.

82
Q

siRNA

A

derived from exogenous dsRNA. Requires complete nucleotide pairing –> highly specific mRNA targeting –> mRNA cleavage prior to translation
KNOCK DOWN

83
Q

Hardy Weinberg

A

p+q=1
p^2 + 2pq +q^2 = 1
if no mutations at locus, no natural selection, random mating, no migration, large population.

84
Q

Prader Willi Syndrome

A

IMPRINTING Chromosome 15 Paternal
Maternally derived genes are silenced. Disease occurs when the paternal allele is deleted.
Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia.

85
Q

AngelMan Syndrome

A

IMPRINTING Maternal UBE3A Chromosome 15
Paternally derived UBE3A is silenced. Disease occurs when the maternal allele is deleted.
Seizures, ataxia, intellectual disability, inappropriate laughter.

86
Q

Cystic Fibrosis

A

AR defect in CFTR on Chromosome 7 (del Phe508)
White
mut. ATP gated Cl- channels (retained in RER) –> decreased Cl- secretion and increase Cl- intracellularly –> Na+ reabsorption via ENaC –> increase H2O reabsorption –> abnormally thick mucus secreted into lungs and GI tract.
Increased Cl- in sweat.
Recurrent pulm infection, pancreatic insufficiency (steatorrhea, meconium ileus), infertility in men, Nasal polyps, clubbing of nails.
T(x): saline, albuterol, pancreatic enzyme replacement.

87
Q

Duchenne

A 
X linked (frameshift deletion or nonsense) DMD gene
Weakness in pelvic girdle muscles and progresses superiorly. Pseudohypertrophy of calf muscles due to fibrofatty replacement of muscle.
Gowers sign (use arms to help stand up)
Increase CK and aldolase
88
Q

Becker

A

X linked non frameshift deletion of DMD gene

89
Q

Myotonic Dystrophy

A

AD CTG repeats in DMPK gene –> abnormal myotonin protein kinase –> myotonia, muscle wasting, cataracts, testicular atrophy, frontal balding, arrhythmia.

90
Q

Rett Syndrome

A

sporadic Women 1-4 years
de novo mut MECP2 on X chromosome
regression in motor, verbal, and cognitive abilities, ataxia, seizures, growth failure, and hand wringing.

91
Q

Fragile X

A

X linked Dominant CGG repeat in FMR1 gene –> hypermethylation –> decreased expression.
Post pubertal macroorchidism, long face with large jaw, large ears, autism, mitral valve prolapse, hypermobile joints

92
Q

Down Syndrome

A

Trisomy 21
intellectual disability, flat facies, prominent epicanthal folds, single palmar crease, duodenal atresia, Hirschsprung disease, ASD, early Alzheimers, increased risk of AML/ALL
Increased hCG and inhibin
Advanced maternal age

93
Q

Edwards Syndrome

A

Trisomy 18
prominent occiput, rocker bottom feet, intellectual disability, nondisjunction, clenched fists with overlapping fingers, low ears, congenital heart disease, omphalocoele.
Death by 1 year

94
Q

Patau Syndrome

A

Trisomy 13
Intellectual disability, rocker bottom feet, micropthalmia, microencephaly, cleft lip, holoprosencephaly, polydactyly, congenital heart disease, PCKD.
Death by 1 year

95
Q

Cri du chat Syndrome

A

congenital deletion on short arm Chromosome 5 (46 XX/XY)

microencephaly, moderate to severe intellectual disability, high pitched crying, epicanthal folds, VSD

96
Q

Williams Syndrome

A

congenital microdeletion of long arm of chromosome 7 (elastin gene)
elfin facies, intellectual disability, hypercalcemia, good verbal skills, extremely friendly with strangers, supravalvular aortic stenosis, renal artery stenosis.

97
Q

Vitamin A

A

Antioxidant, visual pigments, treat measles and APML.
In liver and leafy vegetables.
Deficiency: night blindness, bitot spots, corneal degeneration, immunosuppression
Excess: acute tox (nausea, vomiting, vertigo and blurred vision. Chronic tox (alopecia, dry skin, hepatic tox, HTN.
Teratogenic (cleft palate, cardiac abnormalities.
Contra in pregnancy!

98
Q

B1 (thiamine)

A

cofactor for branched chain ketoacid dehydrogenase, a ketoglutarate dehydrogenase, Pyruvate dehydrogenase, transketolase.
Deficiency: Beriberi, wernicke encephalopathy, Korsakoff
impaired glucose breakdown –> ATP depletion worsened by glucose infusion.
D(x) high RBC transketolase activity following B1 administration

99
Q

B2 (Riboflavin)

A

component of FAD and FMN (succinate dehydrogenase)

Deficiency: cheilosis, corneal vascularization

100
Q

B3 (niacin)

A

NAD+ and NADP+. Derived from tryptophan. Treat dyslipidemia, low VLDL and raise HDL.
Deficiency: Glossitis, pellagra (Diarrhea, dementia, dermatitis)
Excess: facial flushing, hyperglycemia, hyperuricemia.

101
Q

Hartnup

A

AR Deficiency in Tryptophan transporter in proximal renal tubular cells on enterocytes –> neutral aminoaciduria and decrease absorption from the guy –> decreased tryptophan for conversion to niacin –> pellagra
T(x): high protein diet and nicotinic acid.

102
Q

B6 (Pyridoxine)

A

Cofactor for transamination, decarboxylation reactions, glycogen phosphorylase, synthesis of neurotransmitters.
Deficiency: convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemia

103
Q

B5 (Pantothenic acid)

A

Coenzyme A and fatty acid synthase

Deficiency: Dermatitis, enteritis, alopecia, adrenal insufficiency.

104
Q

B7 (biotin)

A

carboxylation enzymes
Deficiency: Dermatitis, enteritis, alopecia. Caused by long term antibiotic use or excessive ingestion of raw egg whites.

105
Q

B9 (folate)

A

Coenzyme for 1-carbon transfer/methylation reactions. DNA and RNA synthesis
Deficiency: Macrocytic, megaloblastic anemia, hypersegmented PMN, glossitis, no neuro symptoms. Caused by phenytoin, sulfonamides, MTX.
D(x): high homocysteine, normal methylmalonic acid (alcoholism and pregnancy)

106
Q

B12 (cobalamin)

A

Cofactor for methionine synthase and methylmalonyl CoA mutase, DNA synthesis.
Deficiency: Macrocytic, megaloblastic anemia, hypersegmented PMNs, paresthesias and combined degeration due to abnormal myelin. Caused by malabsorption (D. latum), achlorydia, bacterial overgrowth, alcohol, lack of intrinsic factor, no terminal ileum, drugs.
D(x): increase homocysteine and methylmalonic acid.

107
Q

C (ascorbic acid)

A

antioxidant, iron absorption, hydroxylation of proline and lysine in collagen synthesis, DA B hydroxylase.
Deficient: scurvy (swollen gums, easy bruising, petechiae, hemarthrosis, anemia, poor wound healing.
Excess: nausea, vomiting, diarrhea, fatigue, calcium oxalate nephrolithiasis.

108
Q

D

A

Increase intestinal absorption of Ca2+ and PO4. increase bone mineralization at low levels, increase resorption at higher levels.
Regulated by increase PTH, decrease Ca2+ and PO4 –> increase 1, 25 OHD3 (inhibits itself)
Deficient: Rickets (kids, osteomalacia (adults)
Excess: hypercalcemia, hypercaliuria, loss of appetite, stupor.

109
Q

E (tocopherol, tocotrienol)

A

Antioxidant (protect RBC from radical damage)
Deficient: hemolytic anemia, acanthocytosis, muscle weakness, demyelination of posterior columns
Excess: enterocolitis in infants.

110
Q

K

A

Activated by epoxide reductase –> blood clotting (2, 7, 9, 10).
Deficiency: neonatal hemorrhage with increased PT and PTT but normal bleeding time.
NOT IN BREAST MILK

111
Q

Zinc

A

zinc fingers and cofactor
deficiency: delayed wound healing, suppressed immunity, male hypogonadism, decreased adult hair. Associated with acrodermatitis enteropathica,

112
Q

Kwashiorkor

A

protein malnutrition

skin lesions, edema due to decreased plasma oncotic pressure, liver malfunction (swollen abdomen)

113
Q

Marasmus

A

malnutrition not causing edema. Diet is deficient in calories but no nutrients are entirely absent.

114
Q

Fomepizole

A

block alcohol dehydrogenase

Antidote for overdoses of methanol or ethylene glycol

115
Q

Disulfram

A

blocks acetaldehyde dehydrogenase –> increase acetaldehyde –> increase hangover symptoms –> discourage drinking.

116
Q

Ethanol metabolism

A

increase NADH/NAD+ ratio in liver –> lactic acidosis (increase pyruvate to lactate), fasting hypoglycemia, ketoacidosis, hepatosteatosis, inhibit TCA cycle.

117
Q

What does the Mitochondria Metabolize?

A

Fatty acid oxidation, acetyl CoA production, TCA cycle, oxidative phosphorylation, ketogenesis

118
Q

What does the Cytoplasm Metabolize?

A

glycolysis, HMP shut, synthesis of cholesterol, proteins, fatty acids and nucleotides

119
Q

What does the Mitochondria and Cytoplasm Metabolize?

A

Heme synthesis, Urea cycle, gluconeogenesis

120
Q

Phosphofructokinase 1

A

Glycolysis (require ATP)
Fructose 6 phosphate –> fructose 1,6 bisphosphate
(+) AMP, fructose 2,6 bisphosphate
(-) ATP, citrate

121
Q

Fructose 1,6 bisphosphatase

A

Gluconeogenesis

(-) AMP, fructose 2,6 bisphosphate

122
Q

Isocitrate dehydrogenase

A

TCA Cycle
(+) ADP
(-) ATP, NADH

123
Q

Glycogen synthase

A

Glycogenesis
(+) G6P , insulin, cortisol
(-) epinephrine, glucagon

124
Q

Glycogen phosphorylase

A

glycogenolysis
(+) epinephrine, glucagon, AMP
(-) G6P, insulin, ATP

125
Q

G6PD

A

HMP shunt
(+) NADP+
(-) NADPH

126
Q

Carbamoyl phosphate synthetase II

A

De novo pyrimidine synthesis
(+) ATP, PRPP
(-) UTP

127
Q

Glutamine PRPP amidotransferase

A

De novo purine synthesis

(-) AMP, IMP, GMP

128
Q

Carbamoyl phosphate synthetase I

A

Urea cycle

(+) N acetylglutamate

129
Q

Acetyl CoA carboxylase

A

Fatty acid synthesis
(+) insulin, citrate
(-) glucagon, palmitoyl CoA

130
Q

Carnitine acyltransferase I

A

Fatty acid oxidation

(-) Malonyl CoA

131
Q

HMG CoA synthase

A

Ketogenesis

132
Q

HMG CoA reductase

A

Cholesterol synthesis
(+) insulin, thyroxine, estrogen
(-) glucagon, cholesterol

133
Q

Hexokinase

A

(glucose –> Glucose 6 phosphate) Require ATP
most tissues except liver and pancreatic B cells, high affinity, low capacity, not induced by insulin, inhibited by glucose 6 phosphate

134
Q

Glucokinase

A

(glucose –> Glucose 6 phosphate) Require ATP

liver and beta cells of pancreas, low affinity, high capacity, induced by insulin, inhibited by fructose 6 phosphate

135
Q

Fasting state

A

increase glucagon –> increase cAMP –> increase PKA –> increase FBPase2 and decrease PFK2

136
Q

Fed State

A

Increase insulin –> decrease cAMP –> decrease PKA –> decrease FBPase2 and increase PFK2

137
Q

Pyruvate Dehydrogenase Complex

A

Active in fed state
Pyruvate –> acetyl CoA
Enzymes: thiamine pyrophosphate, lipoic acid (inhibited by arsenic), CoA, FAD, NAD+
Activated by increased NAD+/NADH ratio, increase ADP and increase Ca2+

138
Q

Pyruvate Dehydrogenase Complex Deficiency

A

X linked
buildup of pyruvate that gets shunted to lactate and alanine
Neuro deficits, lactic acidosis, increase serum alanine
T(x): increase intake of ketogenic nutrients

139
Q

Pyruvate Metabolism

A
  1. Alanine aminotransferase (liver to muscle)
  2. Pyruvate carboxylase (oxaloacetate)
  3. Pyruvate dehydrogenase (TCA cycle)
  4. Lactic acid dehydrogenase (RBC)
140
Q

Electron Transport inhibitors

A

directly inhibit ETC –> decrease proton gradient and block ATP synthesis
Rotenone: complex 1 inhibitor
Antimycin A: complex 3 inhibitor
Cyanide, CO, azide: inhibit complex 4

141
Q

ATP synthase inhibitors

A

Directly inhibit mitochondrial ATP synthase –> increase proton gradient. No ATP is produced
Oligomycin

142
Q

Uncoupling agent

A

increase permeability of membrane –> decrease proton gradient and increase O2 consumption. ATP synthesis stops but ETC continues. Produces heat.
2,4 Dinitrophenol, aspirin, brown fate

143
Q

Gluconeogenesis Irreversible enymes

A

Pyruvate carboxylase
PEP carboxykinase
Fructose 1,6 bisphosphatase
Glucose 6 Phosphatase

144
Q

Pentose Phosphate Pathway

A

provides NADPH and ribose from glucose 6 phosphate.

NADPH used for glutathione reduction in RBC, fatty acid and cholesterol biosynthesis.

145
Q

Oxidative phase of PPP

A

Irreversible

glucose 6 phosphate to 6 phosphogluconate (Glucose 6 phosphate dehydrogenase)

146
Q

Nonoxidative phase of PPP

A

Reversible

147
Q

Glucose 6 Phosphate Dehydrogenase defiency

A

X linked. African Americans. Increased malarial resistance
decrease NADPH in RBCS –> hemolytic anemia, infection
Heinz bodies- denatured globin chains precipitate within RBCs due to oxidative stress
Bite cells

148
Q

Essential fructosuria

A

defect in fructokinase AR
benign asymptomatic. Hexokinase becomes primary.
Fructose in blood and urine

149
Q

Hereditary fructose intolerance

A

Deficiency in aldolase B AR. Accumulation of fructose 1 phosphate –> decrease available phosphate –> inhibit glycogenolysis and gluconeogenesis.
Symptoms present after consuming fruit juice or honey.
Urine dipstick will be (-)
Hypoglycemia, jaundice, cirrhosis, vomiting
T(x): decrease intake of fructose, sucrose and sorbitol

150
Q

Galactokinase deficiency

A

Deficiency in Galactokinase AR
Galactitiol accumulates if galactose is present in diet
Galactosemia and galactosuria, infantile cataracts.

151
Q

Classic Galactosemia

A

Absence of galactose 1 phosphate uridyltransferase AR
Accumulation of toxic substances.
Symptoms develop when infant begins feeding
failure to thrive, jaundice, hepatomegaly, infantile cataracts, intellectual disability
T(x): no galactose or lactose

152
Q

Sorbitol

A

trap glucose by converting to sorbitol via aldose reductase. intracellular sorbitol accumulation –> osmotic damage.

153
Q

Lactase Deficiency

A

Intestinal brush border
Primary: age dependent decline after childhood. (asian, AA, NA)
Secondary: loss of intestinal brush border due to gastroenteritis (rotavirus)
Congenital
Stool- acidic and breath increases H+
Bloating cramps, flatulence, osmotic diarrhea

154
Q

Hyperammonemia

A

Flapping tremor, slurring of speech, somnolence, vomiting, cerebral edema, blurred vision.
increase NH3 changes a ketoglutarate, glutamate, GABA and glutamine
T(x) limit protein in diet

155
Q

Ornitine Transcarbamylase Deficiency

A

X linked Urea Cycle Disorder
Body cannot eliminate ammonia (first few days of life)
increase orotic acid in blood and urine, decrease BUN, symptoms of hyperammonemia

156
Q

PKU

A

Low phenylalanine hydroxylase or BH4 cofactor (AR)
increase pheyl ketones in urine
Intellectual disability, growth retardation, seizures, fair complexion, eczema, musty body order
t(x): decrease phenylalanine and increase tyrosine in diet., BH4 supplement.

157
Q

Maple Syrup Urine Disease

A

blocked degradation of branched amino acids (AR)(isoleucine, leucine, valine) due to decreased branched chain a ketoacid dehydrogenase–> increase a ketoacids in blood
vomit, poor feeding, urine smells like maple syrup, severe CNS defects, intellectual disability, death
T(x): restrict isoleucine, leucine, valine in diet and thiamine supplement

158
Q

Alkaptonuria

A

AR
congenital deficiency of homogentisate oxidase (tyrosine–> fumarate) –> buildup of homogentisic acid in tissues
benign
bluish black connective tissue, ear cartilage and slera
urine turns black on prolonged exposure to air
debilitating arthralgia

159
Q

Homocystinuria

A

AR
excess homocysteine in urine
osteoporosis, Marfanoid habitus, ocular changes, cardiovascular effects, kyphosis, intellectual disability, fair complexion, Lens down and in

160
Q

Cystinuria

A

AR
Renal PCT and intestinal amino acid transporter defect
–> prevents reabsorption of Cystine, ornithine, lysie, arginine. Excess cystine in urine –> hexagonal dtones
T(x): urinary alkalinization and chelating agents
D(x): urinary CN-nitroprusside test

161
Q

Organic acidemias

A

present in infancy with poor feeding, vomiting, hypotonia, high anion gap, metabolic acidosis, hepatomegaly, seizures, organic acid accumulation
inhibit gluconeogenesis and hyperammonemia

162
Q

Propionic acidemia

A

Deficient in propionyl CoA carboxylase –> increase propionyl CoA and decrease methylmalonic acid
T(x) low protein diet limited in Valiine, odd chain FA, methionine, isoleucine, threonine

163
Q

Methylmalonic acidemia

A

deficiency in methylmalonyl CoA mutase or vitamin B12

T(x) low protein diet limited in Valiine, odd chain FA, methionine, isoleucine, threonine

164
Q

Glycogen in skeletal muscle

A

glycogenolysis –> G1P –> G6P –>exercise

165
Q

Glycogen in Hepatocytes

A

stored and undergoes glycogenolysis to maintain blood sugar

166
Q

Von Gierke

A

Deficient glucose 6 phosphatase
Sever fasting hypoglycemia, increase glycogen in liver and kidneys, increase blood lactate, Triglycerides and uric acid, hepatomegaly
T(x) oral glucose, avoid fructose and galactose

167
Q

Pompe

A

Deficient Lysosomal acid a 1,4 glucosidase

Cardiomegaly, hypertrophic cardiomyopathy, hypotonia, exercise intolerance

168
Q

Cori Disease

A

Deficient debranching enzymes

normal blood lactate, cardiomyopathy, fasting hypoglycemia.

169
Q

McArdle Disease

A

Deficient Skeletal Muscle glycogen phosphorylase.
increase glycogen in muscle but muscle cannot break it down –> muscle cramps, myoglobinuria with strenuous exercise, arrhythmia

170
Q

Tay Sachs

A

Deficient Hexaminidase A –> accumulated GM2 ganglioside AR

progressice neurodegeneration, developmental delay, hyperreflexia, cherry red spot, lysosomes with onion skin

171
Q

Fabry Disease

A

Deficient a galactosidase A –> accumulate ceramide trihexoside XR
early: peripheral neuropathy, angiokeratomas, hypohidrosis
Late: renal failure, cardio disease

172
Q

Metachromatic leukodystrophy

A

Deficient Arylsulfatase A –> Cerebroside sulfate AR

Central and peripheral demyelination with ataxia and dementia

173
Q

Krabbe Disease

A

Deficient Galactocerebrosidase –> accumulate glacatocerebroside AR
peripheral neuropathy, destruction of oligodendrocytes, developmental delay, optic atrophy, globoid cells

174
Q

Gaucher Disease

A

Deficient Glucocerebrosidase –> accumulate glucocerebroside AR
Hepatomegaly, pancytopenia, osteoporosis, avascular necrosis of femur, bone crises, gaucher cells

175
Q

Niemann Pick

A

Deficient sphingomyelinase –> accumulate sphingomyelin AR

progressive neurodegeneration, hepatosplenomegaly, foam cells, cherry spot

176
Q

Hurler Syndrome

A

Deficient iduronidase –> accumulate heparan sulfate AR

Development delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly

177
Q

Hunter Syndrome

A

deficient iduronate 2 sulfatase –> accumulate heparan sulfate XR
mild Hurler + aggressive behavior, no corneal clouding

178
Q

Systemic Primary Carnitine Deficiency

A

no cellular uptake of carnitine –> no transport of LCFAs into mitochondria –> toxic accumulation of LCFAs in cytosol
weakness, hypotonia, hypoketotic hypoglycemia, dilated cardiomyopathy

179
Q

Medium chain acyl CoA dehydrogenase deficiency

A

decreased ability to break down fatty acids into acetyl CoA –> accumulate fatty acyl carnitines in blood with hypoketotic hypoglycemia
vomiting, lethargy, seizure, coma, liver dysfunction, hyperammonemia, death

180
Q

Ketone excess caused by…

A

prolonged starvation, DKA, alcoholism (excess NADH)
breath smells like acetone
Urine test for ketones can detect acetoacetate not B hydroxybutyrate

181
Q

Choeslteryl ester transfer protein

A

mediates transfer of cholesteryl esters to other lipoprotein particles

182
Q

Hepatic lipase

A

degrade TG –> IDL

183
Q

Hormone sensitive lipase

A

Degrade TG in adipocytes

184
Q

Lecithin cholesterol acyltransferase

A

catalyze esterification of 2/3 plasma cholesterol

185
Q

Lipoprotein lipase

A

degrade TG in chylomicrons

186
Q

Pancreatic lipase

A

degrade dietary TG in small intestine

187
Q

PCSK9

A

degrade LDL recpetor –> increase serum LDL

inhibition –> increase LDL receptor recycing –> decrease serum LDL

188
Q

Apolipoprotein E

A

Everything except LDL

189
Q

Apolipoprotein A

A

Only HDL

190
Q

Apolipoprotein C

A

chylomicron, VLDL, IDL, HDL

191
Q

Apolipoprotein B48

A

Chylomicron

192
Q

Apolipoprotein B100

A

VLDL, IDL, HDL

193
Q

Abetalipoproteinemia

A

AR, mutation in MTP
Chylomicrons, VLDL, LDL absent, and deficiency in B48, B100.
infant severe fat malabsorption, steatorrhea, failure to thrive. Later retinitis pigmentosa, spinocerebellar degeneration due to vitamin E deficiency, ataxia, acanthocytosis.

194
Q

Hypochylomicronemia

A

AR Lipoprotien lipase or apolipoprotein C deficiency
increase blood level chylomicron, TG and cholesterol
Pancreatitis, hepatosplenomegaly and pruritic xanthomas

195
Q

Familial hypercholesterolemia

A

AD absent or defective LDL receptor or defective B100
increase LDL and cholesterol
accelerated atherosclerodid, tendon xanthomas and corneal arcus

196
Q

Dysbetalipoproteinemia

A

AR defective ApoE.
increase blood chylomicrons, VLDL
premature atherosclerosis, tuberoeruptive and pamar xanthomas

197
Q

Hypertriglyceridemia

A

AD Hepatic overproduction of VLDL
increase blood VLDL and TG
pancreatitis, insulin resistance

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