lecture 7 Flashcards
what is the cell cycle
series of events that cause cell to divide into two daughter cells
what are chromosomes
are nuclear structures that contain units of genetic info.
what is the cell cycle of prokaryotes
period b, period c, and period d
cell cycle in eukartotes
cell cycle divided into two main stages: mitosis, and interphase
why do we need the cell cycle
we need to be able to replace cells and renew them
what are homologous chromosomes
one from each parent, that carry same genes
what are ploidy
number of chromosome sets
what is karyotyping
is a collection of chromosomes in individual;
46 somatic cell, or 23 pairs; 22 autosomes
what is the significance of mitosis
-maintain same chromosomal complement
-development and growth
-cell replacement
-organ regeneration
- organisms that reproduce asexually generate gametes by mitosis
what is cytokinesis in plants
involves formation and insertion of new cell wall that separate daughter nuclei
where does mitosis occur
occurs exclusively in eukaryotic cells
what is prophase
chromosomes condense into compact, rod-like structures
what happens in prometaphase
-nuclear envelope is completely dissolved
- spindles enter in former nuclear area
-microtubules attach to centrosomes
what are kinetochore
-kinetochore is protein structure associated to centromeres
what happens in metaphase
-spindles fully formed
-chromosomes align at spindle midpoint
spindle connection at prometaphase
colchicine inhibits spindle formation and arrest cell at prometaphase
what happens in G1
period of cell growth, before DNA replicates
what happens in S
period when DNA replicates and chromosomal proteins are duplicated
what is G0
cell cycle arrest
what happens in G2
period after DNA replicates; cell prepares for division
what organize the center (MTOC)
centrioles, and microtubules , centrosomes organize the center found in eukaryotic cells
what two mechanisms do mitotic spindles use to move chromosomes
-kinetochore microtubules
-non-kinetochore microtubules
kinetochore movement
microtubules are polymerized elastic structures composed of a- and B- tubulin dimers
kinetochore movement
microtubules are polymerized elastic structures composed of a- and B- tubulin dimers
interphase is made up of what
periods
what happens in anaphase
begins with separation of chromatids and sister chromatids are severed
what happens in telophase
chromosomes decondense
cytokinesis in animal cells
final splitting of membrane, actin and myosin begin process of forming cleavage furrow creating actomyosin ring
what are spindles
-spindles are polymerized long elastic structures
what are diploids
chromosome comprement or 2n
what is haploid
its comprement or n
what are sister chromatin
2 nearly identical copies of chromosomes
what are cohesin
it a protein that holds sister chromatin together
