The Cell Cycle in an Organism DNA Mutations and

							        The Cell Cycle in an Organism
Due to the cell cycle in an organism, that organism is able to grow, repair itself, and
develop. Below are some notes on regeneration (the ability to repair cells), stem cells (the
cells that can develop into many forms to grow, develop and repair the body), and aging
(what happens to cells are you get older.)

Regeneration
   • Regeneration is the ability to _______________ a tissue, an organ, or a part of the
      body
   • Humans have some ability to do this: our _______________, _______________,
      _______________, and _______________ cells can regenerate, but the
      _______________ cells cannot divide and repair themselves
   • Regeneration heals the body part that has been lost
   • Can you think of organisms that can regenerate parts of their bodies?

Specialization and DNA
   • The nucleuses of all of your cells contain the same DNA, but different specialized
       cells of the body activate different parts of DNA to reproduce and function as they
       are meant to.

Stem Cells
   • Human skin, bone, and some other tissues have _______________
      _______________ that allow them to reproduce
   • Stem cells are cells that have yet to “_______________”, so they can become
      _______________ type of cell in the body
   • If specialized cells could “turn on” the segments of genetic information that allow
      them to divide, they could work like stem cells and once again begin dividing.
   • This could lead to important breakthroughs in spinal cord and brain research.

Aging
   • During the process of aging (i.e. you getting older), cells begin to die off.
   • When they die off, they are either not _______________ as quickly as they used
      to, or are not replaced at all.
   • This process changes the structure and function of major processes in the body,
      causing skin to become _______________, bones to lose _______________, and
      causing a weakening in the _______________ system, among other things.

            DNA Mutations and Cancer
Sometimes, the cell cycle ‘misprints’ or copies DNA inefficiently or incorrectly. When
this occurs, the DNA in the mother cell is different that the DNA in the daughter cell,
which means different chemicals are substituted into or are missing from the DNA. This
causes complications, mutations, and other effects. Below are some of those effects, and
the things that cause them.
Mutations
  • Mutations are any _______________ in _______________.
  • Mutations can potentially be helpful, but the vast majority of them are either
      _______________ or _______________
  • Mutations can occur when a chromosome is broken and repaired incorrectly or
      damage can be done to the DNA by the _______________, _______________ or
      harmful _______________ in our body (due to such things as smoking, pollution,
      etc.)

Cancer
  • A group of diseases that is associated with uncontrolled cell division
  • This uncontrolled growth forms a lump called a _______________
  • Some tumors are harmless and are called _______________
  • Harmful cancerous tumors that can spread to other parts of the body are labeled
      _______________

Carcinogens
   • Any substance or energy that causes a genetic _______________
   • There are 3 known types:
      a) _______________ – cause leukemia
      b) _______________ – ultra-violet rays from the sun can cause cancer
      c) _______________ – such as those found in cigarette smoke

Cancer Cells
  • Normal cells communicate and know when they need to reproduce and they do
      not
  • Cancer cells cannot communicate like this and multiply endlessly
  • This causes crowding and the killing of normal cells, and eventually the whole
      organism