Explain what you understand by the terms “binary fusion and binary fission”, stating at least an equation in each case.
Answers
Answer:
Binary fission ("division in half") is a kind of asexual reproduction. ... In binary fission, the fully grown parent cell splits into two halves, producing two pools. After replicating its genetic material, the parent cell divides into two equal sized daughter cells. The genetic material is replicated, then equally split.
Answer: perfect
Explanation:
Binary fission is a type of asexual reproduction most commonly seen in prokaryotes and some single-celled eukaryotes. In this method of asexual reproduction, there is a separation of the parent cell into two new daughter cells. This process happens with the duplication and division of the parent’s genetic material into two parts, where, each daughter cells receive one copy of its parent DNA.
It is a primary method of reproduction in prokaryotic organisms. Binary Fission occurs without any spindle apparatus formation in the cell. In this process, the single DNA molecule begins replication and then attaches each copy to various parts of the cell membrane. When the cell starts to get pulled apart, the original and replicated chromosomes get separated.
However, asexual mode of reproduction has a significant drawback. All resultant cells are genetically identical mirror copies of each other and the parent cell. Most antibiotics work on this principle. If a parent cell is vulnerable to an antibiotic, then all resultant daughter cells are also vulnerable too. If a mutation occurs in their genes, then it can render a particular strain resistant to antibiotics.
Prokaryotes such as E. coli, Archaea as well as eukaryotes such as euglena reproduce through binary fission.
Binary Fission
Binary fission is a form of cell division in eukaryotes. In prokaryotes, it is a form of asexual reproduction
Binary Fission in Bacteria
The process of binary fission is usually rapid, and its speed varies among species. The time required by bacteria to double the number of cells it has is called doubling time. Furthermore, each species requires specific conditions for its growth. These conditions include pH levels, temperature, oxygen, light, moisture, osmotic pressure.
For instance, mesophiles thrive at moderate temperatures ranging from 20°C to 45 °C. The ambient temperature of the human body is 37 °C, which means many of the disease-causing bacteria are mesophiles. Mycobacterium tuberculosis is the bacterium that causes tuberculosis in humans. It divides every 15 to 20 hours, which is very slow when compared to other pathogenic bacteria such as Escherichia coli, which can divide every 20 minutes.
On the other end of the spectrum are the extremophiles. These bacteria can survive extremely harsh conditions such as high temperatures, high salinity, highly acidic environments and more. For instance, the Deinococcus radiodurans is an extremophilic bacteria that can survive a thousand times more radiation than a person can. Under normal circumstances, it can divide every 48 hours. However, when exposed to harsh conditions like drought, it can slow down its growth rate until more favourable conditions arise.
Read more: Bacteria
The steps involved in the binary fission in bacyteria are:
Step 1- Replication of DNA
The bacterium uncoils and replicates its chromosome, essentially doubling its content.
Step 2- Growth of a Cell
After copying the chromosome, the bacterium starts to grow larger in preparation for binary fissions. It is followed by an increase in cytoplasm volume as well as an increase in the number of organelles. Another prominent trait of this stage is that the two strands migrate to opposite poles of the cell.
Step 3-Segregation of DNA
The cell elongates with a septum forming at the middle. The two chromosomes are also separated in this phase.
Step 4- Splitting of Cells
A new cell wall is formed at this phase, and the cell splits at the centre, dividing the parent cell into two new daughter cells. Each of the daughter cells contains a copy of the nuclear materials as necessary organelles.
Amoeba Reproduction-Binary Fission in Amoeba
Amoeba is a unicellular organism, and just like bacteria, it reproduces through binary fission. After replicating its genetic material through mitotic division, the cell divides into two equal-sized daughter cells. In this method, two similar individuals are produced from a single parent cell. An amoeba that is about to undergo division grows larger, and eventually, its nucleus extends and divides into two. The division of cytoplasm follows the division of the nucleus. So, two amoebae are produced from a single parent, and the parent’s identity is technically “lost.”
Read More: Nutrition in Amoeba