Phloem loading in the apoplastic pathway thought to mediate the transport of sucrose from the apoplast into the sieve element– companion cell complex. Which of the following  are involved in such sucrose transporting by apoplast?

a) Sucrose is at a higher concentration in the sieve element–companion cell complex indicates that sucrose is actively transported against its chemical-potential gradient

b) Sugars transport from the apoplast into the sieve elements and companion cells energy driven process

c) Phloem loading in the apoplastic pathway involves a sucrose–H+ symporter

d) the route of phloem loading is−mesophyll cells→ bundle sheath cells→ phloem parenchyma cell→ ordinary companion cell→ sieve elements

Which of the following is incorrect?

TLS Online TPP Program

#Question id: 1584

#Unit 4. Cell Communication and Cell Signaling

Which cell type interacts with both the humoral and cell-mediated immune pathways?

TLS Online TPP Program

#Question id: 16957

#Unit 4. Cell Communication and Cell Signaling

the immune system can be summarized as follows. Which is not correct for immune system?

TLS Online TPP Program

#Question id: 16956

#Unit 4. Cell Communication and Cell Signaling

Polyclonal antibodies are raised against bovine serum albumin in rabbit. Subsequently IgG in the antiserum is purified and digested with either pepsin or papain. Out of the following possibilities, which one is correct?

TLS Online TPP Program

#Question id: 16955

#Unit 4. Cell Communication and Cell Signaling

Stage thymocytes express neither CD4 nor CD8, markers associated with mature T cells. They are therefore called double negative (DN) cells. DN cells first travel to the region under the thymic capsule, a region referred to as the ________, where they proliferate and begin to generate their T-cell receptors. Thymocytes that successfully express TCRs begin to express both CD4 and CD8, becoming double positive (DP) cells, and populate the cortex, the site where most (85% or more) immature T cells are found.

TLS Online TPP Program

#Question id: 16954

#Unit 4. Cell Communication and Cell Signaling

match the following

A. endosteal niche	1. versatile cells that both generate bone and control the differentiation of HSCs
B. osteoblasts	2. line the blood vessels and also regulate HSC differentiation
C. reticular cells	3. send processes connecting cells to bone and blood vessels, and, unexpectedly
D. sympathetic neurons	4. can control the release of hematopoietic cells from the bone marrow.

TLS Online TPP Program

#Question id: 16953

#Unit 4. Cell Communication and Cell Signaling

The ability of any stem cell to self-renew and differentiate depends on the structural organization and cellular function of specialized anatomic microenvironments known as stem cell niches. These sequestered regions are typically populated by a supportive network of stromal cells. Stem cell niche stromal cells express soluble and membrane-bound proteins that regulate cell survival, proliferation, differentiation, and trafficking. Which statements is true about HSCs?