chapter 12: mitosis Flashcards
why do cells reproduce?
for growth (body), cell replacement, healing (skin), reproduction
what is asexual reproduction?
the generation of offspring from a single parent that occurs without the fusion of gametes (usually genetically identical to the parent)
what is a chromosome and what is it made up of?
a cellular structure consisting of 1 DNA molecule and associated protein molecules, it is made up of protein and DNA
what is the cell cycle?
a series of steps where chromosomes and other ell material double to make 2 copies
what happens during prophase?
chromatin begins to condense, centrosomes move to opposite sides of the cell, and the spindle fibers begin to form
what happens during pro metaphase?
the nuclear membrane dissolves and spindle fibers grow/span across the cell (at this point some spindle fibers contact the kinetochores of individual chromosomes)
what happens durning metaphase?
spindle fibers move each chromosome to the middle of the cell, creating a line of chromosomes
what happens during anaphase?
centromeres start to shorten causing sister chromatids to pull apart and spindle fibers continue to shorten
what happens during telophase?
daughter nuclei begin to form, chromosomes start to relax, and the nuclear membrane reforms
what are the stages of the cell cycle?
G1 (gap 1): cell prepares to replicate DNA
S (synthesis): DNA replication
G2 (gap 2): cell prepares to divide
M: mitosis and cytokinesis
what are kinetochores and how do they work?
they are structures of proteins attached to the centromere that links each sister chromatid to the mitotic spindle
what are spindle fibers made of?
microtubulin
how do sister chromatids move to each end of the cell?
during anaphase, centromeres start to shorten which results in the sister chromatids pulling apart and separating
what is mitosis?
occurs when a parent cell duplicates its contents and splits into 2 identical daughter cells
what is meiosis?
cell division that reduces the number of chromosomes in the parent cell by half, producing 4 sex cells (gametes)
