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