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#Question id: 5670


Embryonic stem cells can be induced in the laboratory to differentiate into muscle, nerve, pancreatic, and other specialized cell types. It has recently become possible to trigger the dedifferentiation of somatic cells back into pluripotent cells (so-called induced pluripotent stem cells or iPS cells) by artificially enhancing the production of a relatively small number of key transcriptional factors known to be required for maintenance of pluripotency. Examples of such transcription factors are OCT4 and NANOG. The production of OCT4 and NANOG (and other key regulatory proteins) is stimulated by a transcription factor known as FOXP1, a member of the Forkhead family of DNA-binding proteins. There are two isoforms of FOXP1.

Which of the following statement regarding to FOXP1 is incorrect?

#Unit 5. Developmental Biology
  1. The protein encoded by the exon 18b–carrying mRNA is called FOXP1-ES: this activates genes (OCT4, NANOG, etc.) that promote dedifferentiation, and thus stimulates iPS cell formation.

  2. In the exon 18a–containing form encodes FOXP1 itself, and this has the opposite effect: it fails to stimulate expression of OCT4 and NANOG and instead actives genes that promote differentiation.

  3. FOXP1 binds to DNA via a domain known as a Winged helix, which recognizes a particular DNA sequence.

  4. The switch from exon 18a to exon 18b substitutes 3 residues in the Winged helix region of the protein including six amino acids that are known to contact DNA.

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TLS Online TPP Program

#Question id: 12951

#Unit 7. System Physiology – Animal

If the cortical collecting tubule tubular fluid inulin concentration is 40 mg/100 ml and plasma concentration of inulin is 2.0 mg/100 ml, what is the approximate percentage of the filtered water that remains in the tubule at that point?

TLS Online TPP Program

#Question id: 12950

#Unit 7. System Physiology – Animal

Increases in both renal blood flow and GFR are caused by which of the following?

TLS Online TPP Program

#Question id: 12949

#Unit 7. System Physiology – Animal

At which renal tubular sites would the concentration of creatinine be expected to be highest in a normally hydrated person?

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#Question id: 12701

#Unit 7. System Physiology – Animal

In chronic respiratory acidosis with partial renal compensation, you would expect to find the following changes, compared to normal:___ urinary excretion of NH4+; ______ plasma HCO3− concentration; and _____ urine pH.

TLS Online TPP Program

#Question id: 12700

#Unit 7. System Physiology – Animal

A young man is found comatose, having taking an unknown number of sleeping pills an unknown time before. An arterial blood sample yields the following values: pH = 7.02, HCO3− = 14 mEq/L, and PCO2 = 68 mm Hg. This patient’s acid–base status is most accurately described as

TLS Online TPP Program

#Question id: 12699

#Unit 7. System Physiology – Animal

The following test results were obtained: urine flow rate = 2.0 ml/min; urine inulin concentration = 60 mg/ml; plasma inulin concentration = 2 mg/ml; urine potassium concentration = 20 μmol/ml; plasma potassium concentration = 4.0 μmol/ml; urine osmolarity = 150 mOsm/L; and plasma osmolarity = 300 mOsm/L. What is the free water clearance rate?