TLS Online TPP Program

#Question id: 7254


Following statements regarding to the micromeres specification and regulatory input  in sea urchin embryo. Which of the following statement is correct?

#Unit 5. Developmental Biology
  1. OTX is a general transcription factor, and β-catenin from the maternal cytoplasm is concentrated at the vegetal pole of the egg. These transcriptional regulators are inherited by the macromeres and activate the Pmar1 gene.
  2. Pmar1 encodes a repressor of HesC, which in turn encodes activator of several genes involved in micromere specification.
  3. In the veg2 cells, Pmar1 is not activated and the HesC gene product shuts down the non-skeletogenic genes.
  4. As soon as the micromeres form, maternal β-catenin and Otx activate the Blimp1 gene, whose product activates the Wnt8 gene. Wnt8 protein is then received by the same micromeres that made it (i.e., autocrine regulation), activating the micromeres’ own genes for β-catenin.
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TLS Online TPP Program

#Question id: 11743

#Unit 6. System Physiology – Plant

The wall between the two mature sieve tube elements contain a sieve plates, these sieve plate pores are open —that is, unobstructed by

TLS Online TPP Program

#Question id: 11744

#Unit 6. System Physiology – Plant

Large pores in cell walls are the prominent feature of sieve elements, the sieve area pores range in diameter from

TLS Online TPP Program

#Question id: 11745

#Unit 6. System Physiology – Plant

sieve cells of the sieve elements of phloem conduct sugars throughout the plant. The following statements given about characteistics of Sieve cells of sieve elements in seed plants;

a.)  There is no P-protein in gymnosperms

b.) Angiosperm contains sieve plate pores are open channels

c.) Pores in sieve areas appear blocked with membranes in gymnosperms

d.) Companion cells are sources of ATP and perhaps other compounds

Which of the following combination is correct?

TLS Online TPP Program

#Question id: 11746

#Unit 6. System Physiology – Plant

Sieve element sap is rich in sugars and other organic molecules, These molecules represent an energy investment for the plant. How their loss be prevented when sieve elements are damaged?

TLS Online TPP Program

#Question id: 11747

#Unit 6. System Physiology – Plant

A mechanism for preventing sap loss entails closing sieve plate pores with callose, which is

TLS Online TPP Program

#Question id: 11748

#Unit 6. System Physiology – Plant

In mature cells, P-protein occurs in several different forms depending on the species. Such as;