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.
Answer:
A. Rheumatoid arthritis is characterized by periods of remission and exacerbation
C. Rheumatoid arthritis can cause fatigue and weight loss
Explanation:
Answer 1: Difference b/w wet and dry earwax genes is due to switch of a single DNA unit i.e. single nucleotide polymorphism.
Answer 2: Earwax is important in many ways mainly it is a biological flypaper as it prevents dust and insects from entering the ear.
Answer 3: Genetics have proved that for those who sweat a lot and have armpit odor have wet earwax.
Answer 4: The wet type earwax is dominant one with honey brown or dark brown color while dry one is recessive.
Answer 5: As wet earwax is dominant trait, according to the given scenario the genotype of parent with wet earwax will be "WW" which when crossed with dry earwax parent will have all the offsprings with wet earwax.
Answer:
Living things
Explanation:
Living Things depend on OTHER LIVING THINGS and NON-LIVING THINGS to survive.
Organisms immune to rapid salinity changes
