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Cell Reproduction

Chapter 8
STUDY
PLAY
chromosomes
rod-shapes structures made of DNA and protein
histones
DNA wraps around histones in eukaryotes to help maintain the compact structure of chromosomes
sex chromosomes
determine the sex of an organism
XX
female
XY
Male
autosomes
all of the other chromosmes in an organism
diploid cells
cells having two sets of chromosomes
ex: autosomes
haploid cells
cells having only one set of chromosomes
ex: sex chromosomes
cell division
the process by which cells reproduce themselves
binary fission
the process of cell division in prokaryotes
cell cycle
- the repeating set of events in the life of a cell
- consists of a cell division and interphase
- cell division includes mitosis and cytokenisis
interphase
consists of growth, DNA replication, and preparation for cell division
mitosis
results in two offspring cells that are geneticall identical to the original cell
cytokinesis
- in animal cells, a cleavage furrow pinches in and eventually separates the dividing cell into two cells
- in plant cells, a cell plate separates the dividing cells into two cells
when control of cell division is lost
cancer may result if the cells aren't able to respond to the control mechanisms
Interphase
- chromosomes are copied # doubles
- chromosomes appear as threadlike coils (chromatin)
- chromosomes change to sister chromatids at the end of the phase
Prophase
- centrioles appear and begin to move to opposit ends of cell
- spindle fibers form between the poles
metaphase
- chromatid attach to the spindle fibers
anaphase
- chromatids separate and begin to move to opposite ends of the cell
telophase
- two new nuclei form
- chromosomes appear as chromatin
- mitosis ends
cytokinesis
-0 cell membrane moves inward to creat two daughter cells - each with its own nucleus with identical chromosomes
meiosis
- process of nuclear division that reduces the number of chromosomes in new cells to half the number in the original cell
- leads to four haploid cells (gametes) rather than two diploid cells as in mitosis
crossing over
when portions of homologous chromosomes exchange genetics material, occurs during prophase 1 and results in genetic recombination
spermatogenesis
the process by which sperm cells are produces
oogenesis
the process that produces mature egg cells
sexual reproduction
the formation of offspring through meiosis and the union of a sperm and an egg
types of asexual reproduction
- budding
- fission
- fragmentation
homologous chromosomes
pairs of chromosomes that contain the same genes; crossing over between homologous chromosomes insures genetic variation within a species