Cell Division
Appoximately what % of the time in the cell cycle do you think interphase occupies
90
Sample Name
Allium(onion) root tips Fish Blastodisc
Sample magnification
Both HPM 40x
Cytokinesis Plant Cells
Cell Plate begins cell wall formation between two daughter cells.
G2 Phase
Cell growth and protein synthesis
g1 phase
Cellular organelles begin to duplicate.
_____ are not typically present in plant cells.
Centrioles
Cytokinesis animal cells
Cleavage furrow forms from the outside in
______ and other plant chemicals also have medical uses for people, mainly for use in cancer chemotherapy to stop tumor cells from dividing, thus causing remission of the cancer.
Colchicine
What happens to the DNA by the end of the "S" phase of interphase?
DNA replication
S-Phase
DNA replication (chomosomes become doubled)
what region are the parts of plants where cell division actively occurs.
Meristematic regions (or meristems)
Mitotic-Phase:
Period of Cell Division
Interphase
Period when cell is not dividing
Mitosis phases
Prophase, Metaphase, Anaphase & Telophase
the stage of the cell cycle where the pairs of chromosomes seperate to opposite sides of the cell
anaphase
the two identical sister chromatids that make up each chromosome separate from each other at the centromere region. The sister chromatids will now form the single chromosomes that move to opposite ends (poles) of the cell. When the chromatids separate from each other they are no longer called chromatids. They are now referred to as single _______. The single chromosomes are actually being pulled to opposite ends of the cell as the spindle fibers shorten.
anaphase chromosomes
Now we are back to interphase again, but now there are two daughter cells. Each daughter cell is chromosomally identical with the original (mother) cell. They each have a nucleus that contains a nucleolus and _____. During this phase the chromosomes will replicate and become distinct pairs of sister chromatids as each daughter cell enters prophase.
chromatin
Cytokinesis (cytoplasmic division)
cleavage furrow in animal cells and cell plate in plant cells formed during telophase of cell division.
The autumn crocus contains a chemical called ______ which depolymerizes the proteins in mitotic spindle fibers. This essentially dissolves the spindle and stops the cell from completing its mitotic division.
colchicine
the division of the cytoplasm that creates 2 new cells
cytokinesis
Interphase 3 parts
g1, s phase, g2
eukaryotic cells during mitosis, in which a parent (or mother) cell divides into two _______ daughter cells that have the same number of chromosomes as the parent cell.
identical
Which stage of mitosis was most common in the meristematic region of your Allium root tip slide?
interphase
period in which cell is not actively dividing
interphase
the stage of the cell cycle between periods of division
interphase
which stage of the cell cycle takes the longest to occur?
interphase
The nucleus contains darkly stained _______, a term that applies to all of the chromosomes (DNA) collectively. At this stage the chromosomes are threadlike and are not visible as distinct bodies. A nucleolus is clearly visible inside the nucleus. This body is composed of ribosomal RNA. Prior to cell division, two pairs of protein bodies called ______ are present in the cytoplasm at one end of the cell. what phase and fill in blank
interphase chromatin centrioles
polyploid plants with 2 extra sets of chromosomes typically produce
larger flowers and fruits
The cell cycle
life of a cell, from cell division to the period when a cell is not dividing
the stage of the cell cycle where the pairs of identical chromosomes line up across the midplane of the cell
metaphase
The chromosome (recall, each chromosome is now in the form of two, identical sister chromatids) become arranged in the central region of the cell known as the ______. We refer to this as the formation of the metaphase plate. Protein threads called the ______ connect the centromere region of each chromosome with the centrioles at the poles of the cells. what phase and fill in blank
metaphase equator spindle fibers
the process of cell division when 1 cell divides into 2 identical cells with the same # and type of chromosomes is called
mitosis
what is polyploidy
organism has an extra set of chromosomes.
In fact, many of the fruits and vegetables sold at supermarkets are _____ varieties.
polyploid
stage of cycle where chromsomes 1st become visible
prophase
the nuclear membrane and nucleolus begin to dissolve and the chromatin shortens and thickens so that they are visible as distinct rod-shaped bodies called ______. At this time each chromosome is doubled and consists of two identical sister chromatids. Each chromatid is essentially composed of a greatly coiled DNA molecule and protein. The chromatids are attached in a region known as the ____ what phase and fill in blank
prophase chromosomes centromere
the stage of cell cycle where chromosomes duplicate
s phase
The undifferentiated cells of an early human embryo a few days old are called
stem cells
because polyploids with 1 extra set of chromosomes are
sterile and seedless
stage of cell cycle when the nucleus begins to reform
telophase
the chromosomes at each end of the cell begin to organize into separate nuclei, each surrounded by a nuclear membrane. Cytoplasmic division (cytokinesis) in a plant cell is accomplished by the formation of a partition or cell plate between the two newly formed daughter nucle
telophase
Plant meristems are at
the tips of most roots, stems, branches, and buds
Thus, the only parts where plants can increase in length are at the
tips of roots, stems, and branches
Stem cells give rise to various
tissues and organs in the body
Two chemicals (what are they) from the Madagascar periwinkle are also potent spindle "poisons." These chemicals have proven to be very effective in chemotherapy treatments for
vinblastine and vincristine leukemia and Hodgkin's disease