Cellular Biochemistry Flashcards
Function of RT-PCR
Detects and Quantifies mRNA
Function of Rough Endoplasmic Reticulum
Cell membrane Protein Synthesis
Function of Smooth Endoplasmic Reticulum
Lipid Synthesis
Function of Fibronectin
Binds to integrins, serving as mediator of cell adhesion and migration
RAS Gene Inactive in
Inactive in GDP bound state
RAS Gene Active in
GTP bound state
Function of Ubiquitin
Labelling proteins for degradation by Proteasomes
Fasting State Hormones
Glucagon and Epinephrine
Prolonged Fasting State Hormones
Cortisol
Amino Acids Needed for Purine Synthesis
Glycine, Aspartate and Glutamate
Action of 5 Flurouracil
Inhibition of Methylation of Uracil to Thymine
Nucleosome
Negatively charged DNA loops twice around positively charged histone octamer
Which phase does DNA and histone synthesis occur
S phase
HISTONE METHYLATION
Histone Methylation Mostly Makes DNA Mute.
HISTONE ACETYLATION
Histone Acetylation makes DNA Active.
Mitochondrial DNA
Most common non-nuclear DNA found in eukaryotic cells
Small circular chromosomes.
Mitochondrial DNA mutation
Diseases arising from mutations in mtDNA are transmitted from the mother to all of her offspring.
What are the amino acids needed for pyrimidine synthesis
Aspartate and Glutamine
What are the amino acids needed for Purine synthesis
Glycine
Aspartate
Glutamine
Precursor for all pyrimidines
Orotic acid
What are Telomeres
Long stretches of repetitive sequences at the end of chromosomes.
Importance of telomeres
When the length of telomeres is exhausted, the cells often become quiescent or undergo apoptosis
Exons
Contain the actual genetic information coding for
protein.
Introns
Intervening non coding segments of DNA.
Function of NADPH
- Cholesterol and Fatty acid synthesis
- Antioxidant mechanism for RBC
Function of Telomerase
Adds TTAGGG to 3’ end of chromosome
Topoisomerase function
Prevents supercoiling and strand breakage
Nucleotide Excision Repair
Remove large distortion
(Answer if UV Light Damage in question)
Base Excision Repair
Removal of Single base
(Answer if question mention glycosylases)
Recombinational dsDNA repair
Defect repaired using complimentary strands from homologous dsDNA
(Answer if question mentions BRACA or Fanconi Anemia)
Splice Site mutation
Intron retained in mRNA
(Answer if question with mutation of intron sequence)
Smooth Endoplasmic Reticulum function
Synthesises steroids and lipids
Rough Endoplasmic Reticulum function
Protein synthesis for use outside cell
Free Ribosome function
Produce proteins which are used intracellularly
Golgi body function
Process and package proteins
Location of enzyme defect in I cell disease
Golgi body
Enzyme inhibited by Arsenic
Pyruvate Dehydrogenase
Enzyme affected in Mushroom Poisoning (Amanita phalloides)
RNA Polymerase 2
Wnt Pathway
Controls migration of cells essential for embryogenesis
NF-k beta pathway
Leads to activation of immune cells
Action of Insulin
Increase Lipogenesis
Increase glycolysis
Increase glycogenesis
Decrease Gluconeogenesis
Lab values in Vitamin D deficiency
Decreased calcium
Decreased Phosphate
Decreased Calcitriol
Increased PTH
Which DNA repair mechanism can repair neurons
Non Homologous End Joining
What is the result of methylation of CpG islands within the promoter region?
Repression of gene transcription (CpG methylation makes DNA mute)
What process changes the expression of a DNA segment without changing the sequence
DNA methylation
Which enzyme is affected in orotic aciduria?
UMP synthase
What enzyme do mycophenolate and ribavirin inhibit?
Inosine monophosphate dehydrogenase
What drug inhibits dihydroorotate dehydrogenase
Leflunomide
Dihydrofolic acid (DHF) is converted to tetrahydrofolic acid (THF) by which enzyme
Dihydrofolate reductase
Name 2 drugs that decrease deoxythymidine monophosphate (dTMP)
5-Fluorouracil (5-FU)
Methotrexate (MTX)
(dUMP) is converted to deoxythymidine monophosphate (dTMP) by which enzyme?
Thymidylate synthase
mechanism of action of drug 6-mercaptopurine and azathioprine
blocking conversion of phosphoribosyl pyrophosphate (PRPP) to inosine monophosphate
Name the key intermediate that is common to the de novo synthesis pathway of both purines and pyrimidines.
Phosphoribosylpyrophosphate (PRPP)
Lesch-Nyhan syndrome
self-mutilation behaviors, intellectual disability, gout and lactic acidosis
Lesch-Nyhan syndrome finding on blood smear is
Hyper segmented neutrophils
severe combined immunodeficiency disease (SCID) is due to
Deficiency of adenosine deaminase
SCID clinical features
Absence of a thymus
Failure to thrive
Recurrent infections
A low WBC count
Mechanism of rasburicase
Converting uric acid to soluble allantoin
7-year-old complaining of frequent, severe, debilitating episodes of pain in her arms and legs that resolve after a few days. The patient appears fatigued and has pale conjunctivas. Her abdomen is soft with palpable splenomegaly.
Sickle cell anemia (Missense mutation)
What 2 processes occur during the M phase
Mitosis (splitting of the nucleus) and cytokinesis (splitting of the cytoplasm)
Site of synthesis of Insulin
Rough endoplasmic reticulum.
Ataxia, scaly skin, long-standing night blindness, and shortened 4th toes
Refsum disease
Zellweger syndrome - clinical manifestations
Hepatomegaly, hypotonia, and seizures
Which enzyme regenerates UDP-glucose from UDP-galactose
4-epimerase
Why might high succinyl-CoA levels still be noted after treatment of anemia due to vitamin B12 deficiency?
decreased vitamin B6 (which is required for the conversion of succinyl-CoA to heme)
Which cofactor is used in the conversion of dopamine to norepinephrine
Vitamin C
How does the presence of excess ammonia result in inhibition of the tricarboxylic acid cycle (TCA)
Hyperammonemia depletes α-ketoglutarate stores, a key TCA intermediate
What are the 3 direct electron transport inhibitors of complex IV?
Cyanide, carbon monoxide, and azide (the -ides);
What compound directly inhibits complex I
Rotenone (inhibits complex one)
How does oligomycin affect ATP production in the electron transport chain
Inhibits mitochondrial ATP synthase
What compound directly inhibits complex III
Antimycin A
Enzymes inhibited in Lead Poisoning
δ-aminolevulinic acid dehydratase and ferrochelatase
Thyroid hormone is made from which Amino Acid
Tyrosine, and the amino acid phenylalanine is a precursor to tyrosine.
What is the main component of pulmonary surfactant
Phosphatidylcholine
milky-white plasma on Blood draw
Type 1 familial dyslipidemia
skin blistering on sun-exposed areas of his body
Tea-colored urine
mildly elevated transaminases
porphyria cutanea tarda (PCT)
porphyria cutanea tarda (PCT) deficiency of
uroporphyrinogen decarboxylase
Function of Vitamin K
Carboxylation of glutamic acid residues
Mechanism of Absorption of Vitamin A
Micelle-mediated transport
Mechanism of Absorption of Iron
apoferritin-mediated transport
Mechanism of Absorption of Vitamins B7, B5 and C
Sodium-dependent cotransport
Mechanism of Absorption of Calcium
Vitamin D–dependent binding protein–mediated transport
Why Niacin is used with caution to control dyslipidemia in Diabetics
Excess Niacin can result in Hyperglycemia
Findings in Vitamin K Deficiency
Increased PT
Increased APTT
Normal BT
What is the marker for Nucleus
DNA, RNA Polymerase
What is the marker for Lysosome
Acid Phosphatase
What is the marker for Peroxisome
Catalase
What is the marker for Cytosol
LDH
What is the marker for Rough ER
Glucose 6 Phosphatase
