Cell Cycle, Mitosis, and Cancer Flashcards
WHAT IS THE CELL CYCLE?
It is born, it grows,
reproduces and dies
It is divided into two stages:
GROWTH STAGE
(INTERPHASE)
DIVISION STAGE
(MITOSIS AND CYTOKINESIS)
DESCRIBE INTERPHASE
The cell spends almost 90% of its life growing
Cell grows and carries out its normal functions
Cell also makes copies of its organelles and DNA
Cell also makes mistakes and fixes them before cell
division starts
FACTS ABOUT CELLS
Cells do not divide continuously.
Most of the life of a cell is spent in
interphase during which time
hundreds of specific functions are
performed:
Growth, obtaining energy,
synthesizing products like hormones,
repairing damage, and fighting disease.
Different types of cells spend
different lengths of time in the
phases of the cell cycle
WHAT ARE THE STAGES OF INTERPHASE?
G1 (Growth) Phase:
the cell is growing and carrying out
metabolic activities
(eg. producing proteins)
S (Synthesis) Phase:
- the cell makes (synthesizes) an
entire identical copy of its DNA
G2 (Growth) Phase:
- the cell moves into its second growth phase where it approaches its maximum size and produces the structures needed for mitosis (cell division)
WHAT IS THE DIVISION STAGE?
Mitosis
- Contents of the cell
divide equally - Focus is on the
chromosomes (DNA) - form 2 new daughter
cells
Cytokinesis
- Cytoplasm & organelles
divide equally - Cell separates into 2
identical daughter
cells
WHAT PHASE DOES THE cell grow, create for organelle, and DNA is duplicated?
Interphase
WHAT OCCURS IN PROPHASE?
Chromosomes coil
and thicken
2 sister chromatids
held together by a
centromere to make
1 chromosome
Nuclear Membrane
disappears
Centrioles start to
move to opposite
poles
Spindle fibres start
to form
METAPHASE?
Centrioles are now located on
opposite poles
Spindle fibres attach to the
centromere and align chromosomes
at the centre of the cell
The centre is known as the:
Metaphase plate or Equatorial Plate
ANAPHASE?
Chromosomes split
sister chromatids go
towards opposite
poles
TELOPHASE?
Nuclear membrane forms around
the nucleus of each set
Chromosomes stretch out and become thin (chromatin)
CYTOKINESIS?
Cell membrane forms around each new cell
2 distinct daughter cells are formed
Chromosome are unraveled to resume Interphase
CYTOKINESIS:
PLANTS VS. ANIMALS
Animal Cell
Cleavage Furrow
forms
Plant Cell
Cell plate forms
CANCER
a group of diseases when
cells grow and divide out of
control
The DNA code in a cell has changed (mutated), causing one or more of the cell cycle checkpoints to fail.
The mutated cell and all its
daughter cells divide
uncontrollably
can be hereditary or caused
by environmental factors
WHAT IS A TUMOUR?
a lump/mass of
uncontrollably
dividing cells that has
no function.
Can be
benign
malignant
BENIGN TUMOR?
not cancerous
Cells stay in one place and do not seriously affect
surrounding tissues.
can become large enough that it
crowds/compresses surrounding tissues/organs
and affects their normal function.
WHAT ARE MALIGNANT TUMOR?
Cancerous
If they grow into a
blood vessel they
can metastasize
cells of the tumour can destroy or interfere with the function of surrounding tissues
WHAT IS METASTASIS
malignant cancerous cells break away from
“primary” tumour and travel to another part of the
body by way of the bloodstream
once settled, they will begin to divide uncontrollably
again, starting a new “secondary” tumour
cancer becomes extremely difficult to control
and can affect several parts of the body
Benign tumours by definition, do not metastasize
CANCER IN THE LIVER?
The effect of
metastasis is clear in
this cross section of a
human liver.
The pale deposits are
tumours which have
spread throughout
the organ.
SEVERITIES OF CANCER?
A mutation in a normal cell can lead to uncontrolled
cell division.
Cancer only develops if the resulting tumour is
malignant.
If metastasis occurs, the cancer becomes even more
dangerous.
CAUSES OF CANCER?
Changes to the DNA code are
called mutations.
Mutations are the driving force of
evolution.
Very rare mutations may affect the DNA
that controls the cell cycle checkpoints.
If this occurs, the cell does not know
that it should stay in interphase.
Mitosis and cytokinesis occur until all
nutrients are exhausted.
HEREDITARY CAUSES OF
CANCER?
DNA inherited from previous generations may contain mutations that can increase risk of cancer
Examples include:
Some breast and
colon cancers
WHAT ARE CARCINOGENS?
Carcinogens are environmental factors that can
mutate DNA and increase risk of cancer
Examples:
tobacco smoke
x-ray/UV radiation
some viruses
various chemicals
PREVENTIONS OF CANCERs?
- Do not smoke, or quit
- Protect your skin from UVA and UVB rays from the sun. Do not go to tanning salons
- Learn about self examinations for early detection of cancer. A doctor can advise you when additional screening tests are necessary
- Regular exercise can prevent about one third of all cancers
- Eat plenty of fruits and vegetables. Eat less red meat and high fat foods.
HOW TO TREAT CANCER?
SURGERY
Advantage:
If caught early can remove the entire
tumour.
Disadvantage:
Recovery is painful
May not catch it in time to remove all
cancer cells
CHEMO
Advantage:
Effective for spreading cancers.
Disadvantage:
Toxic to healthy cells and can be
very debilitating and painful.
RADIATION
Advantage:
Kills cancer cells
Disadvantage:
Can damage healthy
cells too.
