Answer: Large molecules and wastes move through the membrane through forms of active transport- endocytosis and exocytosis.
Explanation:
Molecules are moved across the cell membrane via different mechanisms like diffusion, facilitated diffusion and passive transport; however, some very large molecules require specialized types of active transport to cross over- these are endocytosis and exocytosis.
During endocytosis large molecules cells and cell fragments moved across the plasma membrane through a process of <em>invagination;</em> piece of the external cell membrane falls into itself and forms a small pocket that surrounds the target molecule this breaks off from the membrane to form an intracellular vesicle. Different methods of endocytosis such as <em>phagocytosis, pinocytosis </em>and receptor-mediated <em>endocytosis</em>, take in cells, water and targeted substances respectively.
Like endocytosis, the particles (signal proteins, neurotransmitters and waste material) are surrounded by a phospholipid membrane. However, in exocytosis, this membrane is formed in the cytoplasm, and merges with the plasma membrane’s interior in a process <em>opposite to </em>endocytosis; material is removed from the cell and exported into the cell’s exterior called the extracellular space.
Explanation:
The cells store glycogen and neutralize toxins and are present in coelomic fluid of some annelids. They are yellowish in colour due to the presence of yellow granules called chloragosomes.
These cells are derived from the inner coelomic epithelium, and help in excretory functions, as most commonly demonstrated in earthworms.
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.
The correct answer will be the second one Growth of a tumor
