hapter 8
8.1
The ability of organisms to reproduce their won kind is the one characteristic that best distinguishes living things from nonliving matter.
Reproduction actually occurs much more often at the cellular level.
Cell division when a cell undergoes reproduction the two daughter cells that result are genetically identical to each other and to original parent cell.
Chromosomes, the structures that contain most of the cell’s DNA. Before the parent cell splits into two, it duplicates its chromosomes.
one set of chromosomes is distributed to each cells. Daugher cell receive identical chromosomes.
Many single celled organisms, such as prokaryotes and eukaryotic yeast cell in reproduce by dividing in half. And the offspring are genetic replicas.
Asexual reproduction, the creation of genetically identical offsping by a singel parent without the participation of sperm and egg. Examples: sea stars (fragmented pieces) houseplant (clipping)
Asxeual reproduction: The lone parent and each of its offspring have identical gene.
Sexual reproduction requires fertilization of an egg by a sper,. Involves a special type of cell division that occurs only in reproductive organs.
A gamete has only half as many chromosomes as the parent cell that gave rise to it. Chromosomes contain unique combinations of genes. In sexual reproducing species, like does not precisely beget like.
The type of cell division responsible for asexual reproduction and for the growth and maintenance of multicelluar organisms involves a process called mitosis. The production of egg and sperm cells involves a special type of cell division called meiosis.
8.2
Prokaryotes (bacteria and archaea) reproduce by a type of cell division called binary fission (divide by half)
Prokaryotes genes are carried on a single circular DNA molecule that with associated proteins, constitutes the organisms chromosome. Prokaryotic chromosomes are much smaller than eukaryotes,.
Binary fission in prokaryote:
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