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TLS Online TPP Program

#Question id: 21250

A 56-year-old female was diagnosed with a tumor near the base of the skull, impinging on her optic tract. Which of the following statements about the central visual pathway is correct?

#Unit 7. System Physiology – Animal
  1. The fibers from each temporal hemiretina decussate in the optic chiasm, so that the fibers in the optic tracts are those from the temporal half of one retina and the nasal half of the other
  2. In the geniculate body, the fibers from the nasal half of one retina and the temporal half of the other synapse on the cells whose axons form the geniculocalcarine tract.
  3. Layers 2 and 3 of the visual cortex contain clusters of cells called globs that contain a high concentration of cytochrome oxidase.
  4. Complex cells have a preferred orientation of a linear stimulus and, compared to simple cells, are more dependent on the location of the stimulus within the visual field.
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TLS Online TPP Program

#Question id: 5137

#Unit 5. Developmental Biology

Match the correct animal and their mechanism of germplasm specification.

Animal

Specification of germ cells

a. Drosophila

i. germplasm is characterized by polar granules and PIE-1 protein, and segregates into P4 during cleavage 

b. Xenopus                                                

ii. germplasm localized in vegetal region of egg

c. mammals

iii. germplasm specified by oskar at posterior end of egg

d. c. elegans

iv. Have no germplasm

TLS Online TPP Program

#Question id: 5138

#Unit 5. Developmental Biology

When presomitic mesoderm (PSM) that would ordinarily form thoracic somites is transplanted into a region in a younger embryo (caudal to the first somite) that would ordinarily give rise to cervical (neck) somites, the grafted mesoderm differentiates according to its original position and forms ribs in the neck. This phenomena is called as:
TLS Online TPP Program

#Question id: 5139

#Unit 5. Developmental Biology

There are two broad categories of receptors that activate tyrosine kinases: (1) those in which the tyrosine kinase enzyme is an intrinsic part of the receptor’s polypeptide chain, called the_________ and (2) those, in which the receptor and kinase are separate polypeptides, encoded by different genes, yet are bound tightly together, called the __________.
TLS Online TPP Program

#Question id: 5140

#Unit 5. Developmental Biology

Following statements regarding to the Ectodermal competence and the ability to respond to the optic vesicle inducer in Xenopus.

A. The optic vesicle is able to induce lens formation in the posterior portion of the ectoderm but not in the anterior portion.

B. If the optic vesicle is removed, the surface ectoderm forms either an abnormal lens or no lens at all.

C. Only head ectoderm is competent to respond to the signals from the optic vesicle by producing a lens.

D. The head ectoderm appears to secrete two paracrine factors BMP 4 and FGF8, which involves in the activation of lens-specific genes such as crystallin.

Which of the following combination is incorrect?
TLS Online TPP Program

#Question id: 5141

#Unit 5. Developmental Biology

Which of the following statement not describe the concept of morphogenetic gradient?
TLS Online TPP Program

#Question id: 5142

#Unit 5. Developmental Biology

The D set of blastomeres is the “organizer” of snail embryos. Experiments have demonstrated that the non-diffusible polar lobe [cortical] cytoplasm that is localized to the D blastomere is extremely important in normal molluscan development.  Which of the following is incorrect?