In a bacterial cell, a protein is synthesized at random location in the cytoplasm. The protein has to reach one pole of the cell for its appropriate function. The protein reaches the pole by
random movement
Protein Movement in Bacterial Cells
In a bacterial cell, many processes occur within the cytoplasm. Proteins are synthesized by ribosomes, which are located throughout the cytoplasm. For a protein to carry out its specific function, it often needs to be located at a particular place within the cell, such as the cell membrane, cell wall, or at one of the cell poles.
The question describes a situation where a protein is made at a random spot in the cytoplasm and needs to get to one of the cell poles.
How Proteins Reach Specific Locations
There are several ways molecules, including proteins, move within a cell:
- Directed Transport: Some proteins have specific signals that are recognized by cellular machinery which actively moves them to the correct location. This is like a targeted delivery system.
- Random Movement (Diffusion): Molecules move randomly due to thermal energy, colliding with other molecules and the surrounding cellular components. This random motion allows them to spread out over time. In small spaces like the cytoplasm of a bacterial cell, diffusion can be quite effective for molecules to travel short distances relatively quickly.
Let's consider the given options in the context of a protein synthesized at a random location needing to reach a pole:
- Chemical attraction: While chemical signals or gradients can direct movement in some cases, simply needing to reach a pole from a random location doesn't inherently imply a strong chemical gradient pulling the protein across the entire cytoplasm, especially if it's a general case for a randomly synthesized protein.
- Random movement: A protein moving randomly through the cytoplasm will explore the available space. Given enough time, this random motion will eventually lead the protein to reach the cell pole, especially in the confined space of a bacterial cell. This is a fundamental process called diffusion.
- Enzymatic action: Enzymatic action typically refers to the chemical reactions catalyzed by enzymes, not a general mechanism for protein transport across the cytoplasm.
- Attraction between opposite charges: Electrostatic interactions based on charge can play a role in specific binding events or localization near charged surfaces, but they are not the primary, general mechanism for a randomly synthesized protein to navigate the bulk cytoplasm to reach a specific pole.
Since the protein is synthesized at a random location and simply needs to reach the pole, without mention of specific targeting signals or machinery, the most fundamental and likely process enabling it to eventually arrive at the pole from anywhere in the cytoplasm is random movement, or diffusion.
Therefore, the protein reaches the pole by random movement within the bacterial cytoplasm.
Important Questions from Cell Division and Cell Cycle
- Choose the correct sequence of steps in the prophase stage of mitosis cell division
A. The polar orientation of the cell for the division into two daughter cells established
B. The nuclear envelop breaks down
C. The nuclear envelop disappears
D. The diffuse chromatin fibers condense and begins to form dense chromosome
Choose the correct answer from the options given below: During cell cycle, entry in the S-phase is tightly regulated. This is possible because:
A. APC/C promotes ubiquitination of S-phase cyclins and mitotic cyclins, marking them for proteolyses at the mitotic exit.
B. Cyclin B1 helps in the activation of S-phase CDKs only in late G1.
C. As mitotic CDK activity declines in late mitosis, cdc14 phosphatase activates APC/C by dephosphorylating Cdh1, thus promoting formation of APC/CCdh1
D. Securin keeps S-phase cyclins in inactive state till late G1.
Which one of the options represents all correct statements?
Following statements were made about cell cycle regulation:
A. De novo synthesis and destruction of Cyclin B are essential for cell cycle progression in yeast.
B. De novo synthesis and destruction of Cyclin B and the related Cyclin dependent Kinase (CDK) are essential for cell cycle progression.
C. CDK activity is regulated by both activating and inhibitory phosphorylation.
D. Retinoblastoma (Rb) functions as an inhibitor of G2 to M transition.
E. Inactivation of Sic 1 is essential for transition into S phase.
Which one of the following represents the combination of the correct statements?
Which one of the following statements about distribution of chromosomes within the interphase nucleus of a mammalian cell is correct?
Following statements were made about cell cycle regulation in eukaryotes:
A. Activity of maturation promoting factor (MPF) rises and falls in synchrony with the concentration of cyclin B.
B. Cdc25 phosphatase mediates removal of phosphate from the inhibitory tyrosine residue (Y15) to yield highly active MPF.
C. MPF specifically phosphorylates and depolymerizes lamin A and C, but not lamin B.
D. MPF phosphorylates H1 histone.
E. In Schizosaccharomyces pombe, overproduction of Wee1 protein decreases the length of G2 phase and extends the period of M phase by functioning as a mediator of MPF activity.
Which one of the following represents the combination of correct statements?
