Combo with Ch 6 bio take home message and 1 other
|6.1 Immortal cells can spell trouble: cell division in sickness and health.||-Cell division is an ongoing process in most organisms and their tissues; disruptions to normal cell division can have serious consequences. |
-In eukaryotic cells, a protective section of DNA called the telomere, at each end of every chromosome, plays a role in keeping track of cell division, getting shorter every time the cell divides.
-If telomeres become too short, additional cell divisions cause the loss of essential DNA and cell death.
-Cells that rebuild their telomeres with each division can become cancerous.
|6.2 Some chromosomes are circular, others are linear||In most bacteria and archaea, the genetic information is carried in a single, circular chromosome, a strand of DNA that is attached at one site to the cell membrane. Eukaryotes have much more DNA than do bacteria and organize it into free-floating linear chromosomes within the nucleus.|
|6.3 Prokaryotes divide by binary fission||Bacteria divide by a type of asexual reproduction called binary fission: first, the circular chromosome duplicates itself, then the parent cell splits into two new, genetically identical daughter cells.|
|6.4 There is time for everything in the eukaryotic cell cycle.||-Eukaryotic somatic cells alternate in a cycle between cell division and other cell activities. -The cell division portion of the cycle is called the mitotic phase. |
-The remainder of the cell cycle, called interphase, consists of two gap phases (during which cell growth and other metabolic activities occur) separated by a DNA synthesis phase during which the genetic material is replicated.
|6.5 Cell division is preceded by replication||-Every time a cell divides, that cell's DNA must first duplicate itself so that each of the two new daughter cells has all the genetic material of the original parent cell. |
-The process of DNA duplication is called replication.
-Errors in replication can lead to mutations, which are changes in the DNA sequence.