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TLS Online TPP Program

#Question id: 1446

Hereditary cancers typically possess loss-of-heterozygosity in:

#Unit 4. Cell Communication and Cell Signaling

  1. proto-oncogenes.

  2. tumor-suppressor genes.

  3. both proto-oncogenes and tumor-suppressor genes.

  4. neither proto-oncogenes nor tumor-suppressor genes.

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TLS Online TPP Program

#Question id: 5672

#Unit 5. Developmental Biology

Following statements are regarding to recognition of sperm by mammalian zona pellucida.

A. Sperm that have undergone the acrosome reaction bind directly to zona protein ZP2 and begin making a channel toward the oocyte.

B. Sperm with an intact acrosome bind to ZP2; they undergo the acrosome reaction on the zona pellucida and then transfer their binding to ZP3.

C. When a sperm reaches the oocyte and fuses with it, the cortical granules release proteins that digest portions of ZP2 and ZP3, making them nonfunctional and prevent polyspermy.

D. When a sperm reaches the oocyte and fuses with it, the cortical granules release proteins that digest ZP3 only, not ZP2 because ZP2 involve in the process of slow block to polyspermy.

Which of the above statements are correct?
TLS Online TPP Program

#Question id: 15662

#Unit 8. Inheritance Biology

You develop an inbred strain of mice that display one of two distinct syndromes. What evidence might lead you to believe that these mice are mutant for a gene or genes affected by imprinting?
TLS Online TPP Program

#Question id: 3681

#Unit 3. Fundamental Processes

 A mutated E. coli cell carries out and completes DNA replication, but the lagging strands are found to contain more errors than normal. These errors are not found evenly distributed throughout the lagging strands, but are found in clusters. Which enzymatic activity is missing from this cell?
TLS Online TPP Program

#Question id: 20282

#Unit 7. System Physiology – Animal

Growth hormone secretion is regulated by negative feedback, three feedback loops including both long and short loops are involved,
a.  GHRH inhibits its own secretion from the hypothalamus via an ultrashort-loop feedback.
b. Somatomedins, which are by-products of the growth hormone action on target tissues, inhibit secretion of growth hormone by the anterior pituitary.
c. Both growth hormone and somatomedins stimulate the secretion of somatostatin by the hypothalamus.
d. SRIF is also secreted by the hypothalmus and acts on the somatotrophs to stimulate growth hormone secretion.
Which one of the following represents all correct statements?
TLS Online TPP Program

#Question id: 4711

#Unit 11. Evolution and Behavior

Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct?