chapter 12 continued - mitosis vocab and mitosis process Flashcards
shortened, condensed dna; tightly wrapped around histone proteins
unduplicated chromosome
two identical copies of a dna molecule, held together at the centromerel; looks like an X under the microscope
duplicated chromosome
a section of dna that stains darker than the rest of the chromosome; point of connection on a duplicated chromosome
centromere
identical halves of a duplicated chromosome
sister chromatids
cell containing two complete SETS of chromosomes; 46 chromosomes in humans (dip/double)
diploid (2n)
cell containing ONE set of chromosomes; 23 chromosomes in humans (hap/half)
haploid (n)
a regular body cell; diploid, and with 46 chromosomes
somatic
a sex cell; sperm/egg, haploid, and with 23 chromosomes in humans
gamete
made of microtubules; push and pull chromosomes around during cell division
spindle fibers
first diploid cell of a new organism; fusion of egg and sperm
zygote
what is the purpose of mitosis?
to create identical diploid somatic cells, for…
- growth
- repair
- replacement
mitosis starts with ________ and ends with ________:
diploid cells; twice as many identical diploid cells
what is the order of phases for cell division (mitosis)?
interphase, mitosis (prophase, metaphase, anaphase, telophase), cytokinesis
interphase
prep phase
cell spends 90% of it’s life cycle here
g1: cell enlarges
s: dna replication occurs
g2: organelles duplicate, prepares to split
prophase
nuclear membrane and nucleolus disappear
spindle fibers and duplicated chromosomes appear
looks like ramen noodles
metaphase
duplicated chromosomes move to the equator
a sister chromatid on either side of the plate
identical cells
zig-zag stitching
cytokinesis
known as cleavage in animal cells, and cell plate formation in plant cells
how does cytokinesis occur in animal cells?
- after mitosis is completed, the spindle begins to disassemble
- at the midpoint of the former spindle, a ring of actin and myosin filaments attached to the plasma membrane contracts
- this contractile ring pulls the cell surface inward as it shrinks
- the ring contracts until it pinches the cell in two
how does cytokinesis occur in plant cells?
- the future plate of division has established before mitosis began. vesicles cluster here when mitosis ends.
- as the vesicles fuse with each other, they form a cell plate along the plane of division
- the cell plate expands outward along the plane of division, when it reaches the plasma membrane, it attaches to the membrane, partitioning the cytoplasm
- the cell plate matures as two new cell walls. these walls join with the parent cell wall, so each descendant cell becomes enclosed by its own cell wall.
tumors
sometimes a checkpoint gene mutates and control over cell division is lost. cells’ uncontrollable division forms an abnormal mass called a tumor
