Answer:
A. S phase
Explanation:
The cell cycle involves all the series of division events that occurs to an organism. Cell division, which can be meiosis or mitosis, involves two main stages viz: Interphase and M phase.
Interphase describes the resting stage of the cell i.e. when the cell is not dividing. The cell uses this time to prepare itself for the next round of division. Interphase stage further consists of three main phases viz: G1, S and G2 phases.
In the S phase or synthesis phase of Interphase, the cell duplicates its genetic material (DNA). Hence, an onion cell observed by a student to have loosely coiled chromatin depicting DNA duplication is in the S-PHASE.
Answer: they drop their leaves and go into dormancy
Explanation:
Check for a diagram on google images :) they have a lot that you can just trace
Answer:
The main function of the RB protein is to inhibit the transition from the G1 to S phase. Its activity depends on its phosphorylation state: if RB is not phosphorylated (active state), it is bound to the transcription factor E2F, preventing its translocation to the nucleus and the activation of genes necessary for DNA synthesis; and if it is phosphorylated, by cyclin-CDK complexes, E2F is released and cell proliferation occurs.
Explanation:
Retinoblastoma (Rb) was the first tumor suppressor described and, as we know today, mutations in its structure determine a large number of cancers. Structurally, we speak of a large and multifunctional protein; which is organized in different domains. The activity of this protein is regulated, mainly, by phosphorylation at multiple sites described over the years and is involved in control mechanisms of the cell cycle, apoptosis and senescence.
