Cell division is the process by which a parent cell divides into two or more daughter cells.[1]Cell division usually occurs as part of a larger cell cycle. In eukaryotes, there are two distinct types of cell division: a vegetative division, whereby each daughter cell is genetically identical to the parent cell (mitosis),[2] and a reproductive cell division, whereby the number of chromosomes in the daughter cells is reduced by half to produce haploid gametes(meiosis). Meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the first division, and sister chromatids are separated in the second division. Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in the last eukaryotic common ancestor.
Prokaryotes (bacteria) undergo a vegetative cell division known as binary fission, where their genetic material is segregated equally into two daughter cells. All cell divisions, regardless of organism, are preceded by a single round of DNA replication.
For simple unicellular microorganisms such as the amoeba, one cell division is equivalent to reproduction – an entire new organism is created. On a larger scale, mitotic cell division can create progeny from multicellular organisms, such as plants that grow from cuttings. Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself was produced by meiotic cell division from gametes. After growth, cell division by mitosis allows for continual construction and repair of the organism.[3] The human body experiences about 10 quadrillion cell divisions in a lifetime.[4]
The primary concern of cell division is the maintenance of the original cell's genome. Before division can occur, the genomic information that is stored in chromosomes must be replicated, and the duplicated genome must be separated cleanly between cells.[5] A great deal of cellular infrastructure is involved in keeping genomic information consistent between generations.
Chemical bond is the right awnser
The correct answer is: B. spinal cord
The nervous system can be divided into two subdivisions: the central nervous system (CNS) and the peripheral nervous system (PNS). The spinal cord and the brain are part of the CNS, whereas the PNS consists of the nerves that radiate from the CNS to all parts of the body. The PNS includes all neurons that sense and transmit information to the CNS.
The CNS controls thinking processes, movements, and registers the sensations throughout our body. Moreover, the PNS acts to transmit information from the CNS to all parts of the body.
The PNS is in turn divided into two main parts:
1-The Autonomic nervous system (ANS), which regulates involuntary functions and glands. The parasympathetic nervous system is one division of the ANS that controls visceral organs such as glands.
2- Somatic nervous system (SNS), which regulates voluntary muscle movement and transmits information from eyes, ears, and skin to the CNS.
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Answer and Explanation:
<u>Cross:</u> aa Bb dd Ee x AA bb Dd Ee
We can calculate the probability of getting heterozygous individuals in the progeny by using the <u>product rule</u>. Assuming that these four genes <u>assort independently</u> (<em>events that occur independently from each other</em>), we can infer that the F1 will have the next genotypic proportions for each gene:
1) aa x AA
F1) 4/4=1 Aa
2) Bb x bb
F1) ½ bb
½ Bb
3) dd x Dd
F1) ½ dd
½ Dd
4) Ee x Ee
F1) ¼ EE
2/4 = ½ Ee
¼ ee
So, to know what the probability is that the F1 of being heterozygous for all loci, we must multiply the respective individual probabilities of getting a heterozygous genotype, like this:
1 Aa x ½ Bb x ½ Dd x ½ Ee = 1/8 AaBbDdEe
They are considered to have originated from cyanobacteria through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell
