10.2 Flashcards
the cells will continue to grow and divide Until…
until they meet up with other cells.
Genetic information is bundled into packages of DNA known as
chromosomes
In prokaryotic cells, DNA is packaged into
a single, circular chromosome.
It is present in the cytoplasm of the prokaryotic cell
Chromosome
The chromosomes in eukaryotic cells form a complex of chromosome and protein called as
chromatin
DNA tightly coils around the histones, and together, the DNA and histone molecules form structures called
nucleosomes
Apoptosis
A process of programmed cell death
Chromosomes shape is
duplicated chromosome with supercoiled chromatin.
In eukaryotic cells, DNA is packaged into
multiple chromosomes
Cells go through a series of events known as the
cell cycle
Binary fission an example
of asexual reproduction that results in two daughter cells that are genetically identical to the single parent cell.
The eukaryotic cell cycle consists of four phases:
G1, S, G2, and M
The life of a cell is one cell division after another separated by an “in-between” period of growth called
interphase
Interphase is divided into three parts
G1, S, and G2
G1 Phase: cell growth
Cell increase in size and synthesize new proteins and organelles.
S phase: DNA replication
New DNA is synthesized when the chromosomes are replicated.
G2 Phase: preparing for cell division
It is the shortest of the three phases of interphase.
•Many of the organelles and molecules required for cell division are produced.
M phase: Cell division
Cell division takes place quickly.
- Cell division occurs in two main stages.
- The first stage, division of the cell nucleus called mitosis.
- The second stage, the division of the cytoplasm called cytokinesis.
Mitosis occurs in four phases
prophase, metaphase, anaphase and telophase.
Prophase: The duplicated strands of the DNA are joined together by a
centromere
Prophase: Each strand is referred as
chromatid or sister chromatids.
Prophase: Spindle fibers forms and extend from a region called
where tiny paired structures called ______ are located.
centrosome
centrioles
Prophase: The nuclear membrane
Breaks apart
Metaphase
The centromeres of the duplicated chromosomes line up across the center of the cell. Spindle fibers connect the centromere of each chromosome to the two poles of the spindle.
Anaphase
The chromosomes separate and move along spindle fibers to opposite ends of the cell.
Telophase
Nuclear envelopes reform, the spindle begins to break apart, and the cell membrane begins to pinch together along the middle of the cell.
Cytokinesis
the cell membrane pinches in the center to form two daughter cells.
In animal cells
Cytokinesis
a structure known as the cell plate forms between the divided nuclei, the cell plate gradually develops into cell membranes that separate the two daughter cells.
In plant cells
When will cells at the edge of the broken bone likely stop dividing rapidly?
when they meet up with neighboring cells, meaning the bone is healed.
Cyclins:
proteins that regulate the cell cycle
The cell cycle is controlled by the regulatory proteins both
inside and outside the cell.
Internal regulators:
respond to events inside the cell
• let cell cycle proceed only when certain steps have already happened
External regulators:
respond to events outside the cell
• direct cells to speed up or slow down the cell cycle
• growth factors: wound healing and embryonic development
is a disorder in which body cells lose the ability to control growth.
Cancer
Cancer cells form a mass of cells called
tumor
Some tumors _ are others are _.
cancerous
benign
Cancer: Uncontrolled Cell Growth
- Cancer cells don’t respond to normal regulatory signals.
- Cell cycle is disrupted.
- Cells grow and divide uncontrollably.
Cancer Formation:
A cell begins to divide abnormally.
- Cells produce a tumor and start to displace normal cells and tissues.
- Cancer cells move to other parts of the body.
What causes cancer?
Cancers are caused by defect in genes called p53 that regulate cell growth and division.
Treatments for Cancer
Surgery to remove localized tumor
- Radiation to destroy cancer cell DNA
- Chemotherapy to kill cancer cells or slow their growth
