Ch. 8 Test Flashcards
define cell division
- the reproduction of cells
- the two “daughter” cells are genetically identical to each other and the original parent cell
what are the purposes of cell division
-growth
-repair
-offspring
compare and contrast asexual and sexual reproduction
similar- they both reproduce
diff- asexual has identical copies while sexual has a variety of offspring
describe a prokaryotic chromosome
- most genes are carried on one circular DNA that constitutes the organisms chromosome
- it is one long curled up string
describe prokaryotic cell division/binary fission
- they divide in half
describe the structure of eukaryotic chromosomes
- contains one large DNA molecule
- DNA molecule is only seen when cell is splitting, otherwise it’s a thin chromatin fiber
define sister chromatids
- when the chromosomes start duplicating, before a cell starts dividing
- two chromatids that are identical
define cell cycle
an ordered sequence of events that run from the time a cell is first formed from a dividing parent cell unit to its own division into two cells
what are the stages in the eukaryotic cycle
-interphase: G1, S, G2
-mitosis: PPMAT
-cytokinesis: the growing phase
what are the phases of interphase
-G1: lots of growth
-S : chromosomes are duplicated
-G2 : more growth and preparing for cellular division
define mitosis
nuclear division
when is the majority of a cell’s life spent in
interphase
define karyokinesis
another term for mitosis
list the stages of mitosis
PPMAT
prophase, prometaphase, metaphase, anaphase, telophase
describe prophase
- chromatin becomes tightly coiled into chromosomes
- forms sister chromatids
- mitotic spindle begins to form
describe prometaphase
- nuclear envelope breaks down
- centrosomes move to the poles and microtubules reach to the chromosomes and attach to the kinetochore (protein that holds sisters together)
describe metaphase
spindle is fully formed and chromosomes line up down the middle of the spindle
describe anaphase
the centromeres pull apart, separating the sister chromatids
describe telophase
- the reverse of prophase
- the chromosomes uncoil and return to chromatin form
- daughter nuclei appear at poles and envelope appears around them to form two new nuclei
describe cytokinesis
- cell division of the cytoplasm
define kinetochore
the protein fibers that connect sister chromatids
what type of cell has cleavage
only animal cells
define apoptosis
cell death
compare cytokinesis in animal and plant cells
- both duplicate cells
- animal cell has cleavage and plant cell uses a cell plate to split
describe the cell cycle control system
a set of proteins that regulate and stop and go of cells dividing
what are the 3 checkpoints in the cell cycle control system
- G1: between G1 and S
- G2: before mitosis
- M: between metaphase and anaphase
describe G0
a permanently nondividing stage (cardiac muscle and nerve cells)
how are cancerous cells different from healthy cells
the divide excessively, forming tumors, they aren’t regulated by the cell cycle
define benign
doesn’t invade other tissues
define malignant
does invade other tissues
define angiogenesis
reroute blood vessel
define metastasis
to spread
define somatic cells
body cells
describe chromosome number in a typical somatic cells
- humans cells have 46
- 23 pairs of homologous chromosomes
describe autosomes
chromosomes other than sex chromosomes that determine all other traits (first 22)
describe sex chromosomes
chromosomes that determine the sex of an individual (last pair)
define locus
carrying the same genes for the same characteristics at the same time
define life cycle
a sequence of generation to generation stages in the history of an organism, from fertilization to the production of its own offspring
define gametes
- eggs and sperm
- are haploid cells with a single set of chromosomes
what’s the difference between haploid and diploid cells
diploid has two sets of chromosomes while haploid only has one
explain the process of fertilization
when a sperm cell fuses with an egg cell, resulting in a fertilized egg or a zygote (has one set of chromosomes from each parent so its a haploid)
what happens in meiosis ll
meiosis one repeats, except meiosis ll results in 4 cells
what are the stages of meiosis
prophase l, metaphase l, anaphase l, telophase l, cytokinesis l, meiosis ll
describe prophase l
when crossing over occurs
describe metaphase l
random alignment
describe anaphase l
sister chromatids remain attached, homologous chromosomes separate
describe telophase l
cleavage furrow
describe cytokinesis
fully separates
describe meiosis ll
- sister chromatids in each chromosomes separate
- results in 4 haploid cells
define tetrads
a set of 4 chromatids
compare and contrast mitosis and meiosis
- they both reproduce, both require ATP
- meiosis has two parts, mitosis is asexual
what are the 3 ways genetic variation is produced
- independent orientation
- random fertilization
- crossing over
define chiasma
the place where two homologous (nonsister) chromatids are attached to each other
define karyotyping
a photographic inventory of an individuals chromosomes
why is karyotyping important
so chromosomal abnormalities can be detected
how do white blood cells support karyotyping
- they’re isolated
- stimulated to grow
- arrested at metaphase
- photographed under a microsope
