Many people may think that DNA replication and cell replication are the same thing, so some people think that human aging may be DNA aging, is this really the case? As a doctor of biology, I would like to popularize science with you today.
01, What is DNA replication?
DNA replication refers to the biological process of duplicating a DNA double strand before cell division, producing two DNA molecules from one original DNA molecule. DNA replication is successfully accomplished through a mechanism called semi-reserved replication.
DNA replication takes place in all organisms that have DNA as their genetic material and is the basis of biological heredity.
02, What is cell replication?
Cell replication is a highly coordinated process that requires the involvement of multiple proteins and enzymes. Among them, cell division proteins and enzymes play a key role. Cytokinesis proteins are indispensable proteins for cell division, and they achieve cell division by regulating changes in the cytoskeleton and changes in cell membranes. Cytokinesis enzymes are enzymes produced during cell division, and they can catalyze the chemical reactions required for cell division, facilitating the progress of cell division. Cell replication not only plays a key role in the development of organisms, but is also associated with the occurrence of many diseases. For example, cancer is a disease caused by abnormal cell proliferation, and abnormal cell replication is often one of the root causes of cancer.
03, the relationship between the two
DNA replication maintains the integrity of DNA genetic information and plays an important role in cell replication. So strictly speaking, DNA replication and cell replication are two different things, although many times, the two are linked.
For example, if there is a house, then the DNA is the people in the house.
If the family has a baby (equivalent to copying), does it mean that the house has suddenly changed? The answer, of course, is no.
DNA replication is controlled by a series of enzymes related to DNA replication, while cellular replication is a more complex series of contents, which is not only the replication of DNA, but also the replication of organelles (such as mitochondria, Golgi apparatus, etc. In addition to this, it also includes the replication of cellular structures, such as typically, the nucleus, the cytoskeleton.
So, in general, although DNA replication is often associated with cellular replication, sometimes the two are not absolutely related.
DNA replicates, but cells do not, as in the typical chromosomal doubling process. The famous colchicine
DNA is not replicated, but cells do, as in the typical chromosome halving process, known as meiosis
04. The problem of human aging
Let's talk about the human aging problem that everyone is most concerned about, human aging is not only DNA aging, but also many other aging, the following is an example diagram in the classic article "The Hallmarks of Aging":
Manifestations of aging include:
基因组不稳定性（genomic instability）
端粒缩短(telomere attrition)
表观遗传学改变（epigenetic alterations）
蛋白内稳态丧失（loss of proteostasis）
营养感应失调（deregulated nutrient sensing）
线粒体功能异常（mitochondrial dysfunction）
细胞衰老（cellular senescence）
干细胞耗竭（stem cell exhaustion）
细胞间信息交换改变（altered intercellular communication）
Genomic instability is only a small part of it, telomeres, epistemes, etc., all affect aging.
Finally, cells do not replicate indefinitely, and even stem cells age.