😱AP Biology Chapter 9: The Cell Cycle

Gary Borisy

________ and colleagues at the University of Wisconsin wanted to determine whether kinetochore microtubules depolymerize at the kinetochore end or the pole end as chromosomes move toward the poles during mitosis.

genetic material

The ________ (DNA) of a cell- its genome- is partitioned among chromosomes.

method of asexual reproduction

A(n) ________ in single- celled organisms in which the cell grows to roughly double its size and then divides into two cells.

metastatic tumors

To treat known or suspected ________, chemotherapy is used, in which drugs that are toxic to actively dividing cells are administered through the circulatory system.

control point

A(n) ________ in the cell cycle where stop and go- ahead signals can regulate the cycle.

kinetochore

The ________ acts as a that attaches the motor of the spindle to the cargo that it moves- the chromosome.

Mitosis

________ is usually followed by cytokinesis.

eukaryotic cells

The process of nuclear division in ________ is conventionally divided into five stages.

meiosis

Chromatids are eventually separated during mitosis or ________ II.

local regulator

(2) A(n) ________ that acts on nearby cells to stimulate cell proliferation and differentiation.

prokaryotic cell

A(n) ________ often has a singular, circular chromosome, which is found in the nucleoid, a region that is not enclosed by a membrane.

Regulation of the cell cycle

________ is carried out by a molecular system, including proteins called cyclins and other proteins that are kinases.

S phase

During ________, DNA replication produces sister chromatids, which persist during G2 of interphase and through prophase, prometaphase, and metaphase of mitosis.

interphase

During ________, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase.

BIG IDEAS

________: The continuity of life depends on a cell cycle in which genetic information from a parent cell is passed on to daughter cells.

nuclear envelope fragments

The ________ and the spindle microtubules attach to the kinetochores of the chromosomes (the second stage of mitosis)

Daughter nuclei

________ are forming and cytokinesis has typically begun (the fifth and final stage of mitosis)

cell division

Bacterial ________ by binary fission: The bacterium E. coli, shown here, has a single, circular chromosome.

G1

There are three major checkpoints in the control system, found in ________, G2, and M phases in a normal cell cycle.

Chromatin

________: The complex of DNA and proteins that make up eukaryotic chromosomes.

University of Colorado

Experiment: Researchers at the ________ wondered whether a cells progression through the cell cycle is controlled by cytoplasmic molecules.

structure present

A(n) ________ in the cytoplasm of animal cells that functions as a microtubule- organizing center and is important during cell division.

Chromosomes

________ condense as a part of cell division, and each chromatin fiber becomes densely coiled and folded, making the ________ shorter and thicker.

Gametes

________ unite during sexual reproduction to produce a diploid zygote.

complex of DNA

The ________ and proteins that makes up eukaryotic chromosomes.

structure of proteins

A(n) ________ attached to the centrosome that links each sister chromatid to the mitotic spindle.

radial array

A(n) ________ of short microtubules that extends from each centrosome toward the plasma membrane in an animal cell undergoing mitosis.

chromatid arms

The chromosome has four ________.

sister chromatids

The mitotic spindle at metaphase: The kinetochores of each chromosomes two ________ face in opposite directions.

light microscope

When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a(n) ________.

Unicellular organisms

________ reproduce by cell division; multicellular organisms depend on cell division for their development from a fertilized egg and for growth and repair.

somatic cells

A chicken has 78 chromosomes in its ________.

external DNA

When the ________ is from a member of a different species, transformation results in horizontal gene transfer.

movement of chromosomes

An assemblage of microtubules and associated proteins that are involved in the ________ during mitosis.

separate daughter cells

The division of the cytoplasm to form two ________ immediately after mitosis, meiosis I, or meiosis II.

DNA

Chromosome: A cellular structure consisting of one ________ molecule and associated protein molecules.

Centrosome

________: A structure present in the cytoplasm of animal cells that functions as a microtubule- organizing center and is important during cell division (moves away during prophase)

binary fission

During ________ in bacteria, the chromosome replicates and the daughter chromosomes actively move apart.

M phase

In the ________, mitosis distributes the daughter chromosomes to daughter nuclei, and cytokinesis divides the cytoplasm, producing two daughter cells.

prokaryotic cell division

Since prokaryotes preceded eukaryotes by more than a billion years, it is likely that mitosis evolved from ________.

Checkpoints

________ allow cellular surveillance mechanisms to determine whether the cell is prepared to go to the next stage.

growth factor

A(n) ________ made by blood cell fragments called platelets is required to divide cultures of fibroblasts.

eukaryotic chromosome

Each ________ consists of one DNA molecule associated with many proteins.

PDGF signals

________ cells by binding to a cell- surface receptor that then becomes phosphorylated, activating it so that it sends a signal.

G1 checkpoint

The ________, called the "restriction point "in mammalian cells, determines whether a cell will complete the cell cycle and divide or switch into the G0 phase.

Centriole

________: A centrosome has a pair of centrioles.

eukaryotic cell cycle

The ________ is composed of and _.

internal signals

Both ________ and external signals control the cell cycle checkpoints via signal transduction pathways.

genetic material

The ________ of an organism or virus; the complete complement of an organisms or viruss genes along with its noncoding nucleic acid sequences.

Mitosis

________ in a plant cell: These light micrographs show ________ in cells of an onion root.

BIG IDEAS

The continuity of life depends on a cell cycle in which genetic information from a parent cell is passed on to daughter cells

Chromosome

A cellular structure consisting of one DNA molecule and associated protein molecules

Chromatin

The complex of DNA and proteins that make up eukaryotic chromosomes

Centromere

Most closely attached

Chromatid

Each of the strands from the chromosome (1 chromatid in a chromosome, a duplicated chromosome has two sister chromatids)

Centriole

A centrosome has a pair of centrioles

Centrosome

A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division (moves away during prophase)

Eukaryotic chromosomes

Chromosomes (stained purple) are visible within the nucleus of this cell from an African blood lily

Differentiate between these terms

chromosome, chromatin, and chromatid

Between divisions, a cell is in interphase

the G1, S, and G2 phases

The Cell Cycle

In a dividing cell, the mitotic (M) phase alternates with interphase, a growth period

The mitotic spindle at metaphase

The kinetochores of each chromosomes two sister chromatids face in opposite directions

Mitosis in a plant cell

These light micrographs show mitosis in cells of an onion root

Bacterial cell division by binary fission

The bacterium E. coli, shown here, has a single, circular chromosome

Mechanisms of cell division

Some unicellular eukaryotes existing today have mechanisms of cell division that may resemble intermediate steps in the evolution of mitosis (Dinoflagellates)

Mechanisms of cell division

Some unicellular eukaryotes existing today have mechanisms of cell division that may resemble intermediate steps in the evolution of mitosis (Diatoms and some yeasts)

In bacterial binary fission, its the opposite

Tubulin-like molecules are thought to act in daughter cell separation, and actin-like molecules are thought to move the daughter bacterial chromosomes to opposite ends of the cell

Experiment

Researchers at the University of Colorado wondered whether a cells progression through the cell cycle is controlled by cytoplasmic molecules

Conclusion

The results of fusing a G1 cell with a cell in the S or M phase of the cell cycle suggest that molecules present in the cytoplasm during the S or M phase control the progression to those phases

Mechanical analogy for the cell cycle control system

In this diagram of the cell cycle, the flat "stepping stones" around the perimeter represent sequential events

Two Important Checkpoints

At certain checkpoints in the cell cycle (red gates), cells do different things depending on the signals they receive

Density-dependent inhibition and anchorage dependence of cell division (cells shown are disproportionately large)

Normal Mammalian Cells

Density-dependent inhibition and anchorage dependence of cell division (cells shown are disproportionately large)

Cancer Cells

The growth and metastasis of a malignant breast tumor

A series of genetic and cellular changes contribute to a tumor becoming malignant (cancerous)