Monday, February 11th, 2013
AIM:
WHAT ARE CANCER CELLS?
Do Now:
Complete the fill in the blank work sheet on “Mitosis and Cell Division”
A little review….
 A gamete is a sex cell.
 Sperm and ova.
Haploid or Diploid?
• A Somatic cell is a body cell.
skin cell, cardiac cell, liver cell, etc.
Haploid or Diploid?






Meiosis
Only occurs in “gonads” (ovaries or testes)
Only produces “germ” cells (reproductive cells)
Involves 2 divisions
1cell2 cells4 cells
Cuts the # of chromosomes per cell in half
Daughter cells receive a variety of different
genetic combinations
 These cells are genetically SIMILAR but NOT
genetically IDENTICAL to the Parent cells.
 * They share the genes from “mom and dad”
Mitosis






“Body Cells”- Occurs all over the body
Produces all “somatic” (non-reproductive) cells.
Completed in 1 division
1 cell  2 cells
maintains the same # of chromosomes per cell
Daughter cells are genetically IDENTICAL to the
original.
 Think about it:
 If you need to make more skin cells, you want them to
be just like your original skin cells. The somatic cells
made need to be IDENTICAL.
Mitosis
Interphase: chromosomes
replicate
Prophase: spindles and
centrioles form
Metaphase:
chromosomes line up in
the Middle.
Anaphase: sister chromatids start
to move to opposite poles.
Telophase: nuclear
membrane reforms
Cytokinesis: 2 daughter cells are
made, identical to the original
parent cell.
Mitosis
Mitosis vs. Meiosis
Cancer
• Caused
by uncontrolled cell division
• Cancer cells don’t function normally,
invade other tissues, monopolize nutrients,
and replace normal cells
•Metastasis: the spread of cancer cells to
other areas of the body
Cancer cells often spread through :
lymphatic system or bloodstream
What are Oncogenes?
Oncogenes: are genes that, when mutated or
expressed at high levels, helps turn a normal
cell into a tumor cell.
• Tumor: solid mass of cells
 All cancers result from genetic changes
(mutations) in the genes which regulate cell
division.
Causes of Oncogenes being turned on:
1. Chromosome replication
errors
2. Viruses
3. Carcinogens
(Mutagens)
Normal Cell Division versus Cancer Cell Division
Risk factors for cancer:
-Family History
-- you can inherit cancer genes
- Aging
-- increases chance of random errors and cell damage
- Impaired Immune System
- a healthy system may destroy cancer cells, so stay
healthy!
- stress and disease can impair immune responses
- Exposure to Carcinogens
- 85-90% of cancers are caused by carcinogens
- UV radiation
-Lifestyle
- smoking, diet, etc.
Smoking
• Increases risk of cancer in:
lung, throat, mouth, bladder,& liver
(also a major risk factor for cardiovascular diseases )
• Chances of living to 80 in USA:
non-smokers 57%; smokers 30%
• Difference in life expectancy:
15 years less for smokers
Diet
There are many things that increase the risk for cancer:
1. Food additives (preservatives,
pesticides, dyes and sweeteners)
2. High fat diets (obesity)
3. Low fiber diets and low anti-oxidant
diets can increase the risk of cancer,
including colon cancer.
-- fruits,
grains and vegetables are high in
fiber and anti-oxidants
Assessment:
Tuesday, February 12th, 2013
Aim:
What are the
differences between
asexual and sexual
reproduction?
Do Now:
Answer this….
How does a healthy cell
become a cancer cell?
(Use your notes from
yesterday)
What is a clone?
Clone:
A genetically identical cell
How to clone an adult mammal:
o Take an embryonic “stem” cell,
remove the nucleus then add a nucleus
from adult
o Implant new cell into female for
development
How to clone a plant:
o Split up cells from existing plant
o Use “tissue culture” to grow
complete plants from each cell
But HOW are clones produced?
• Clones are produced
naturally by mitosis
• Clones can be
produced by genetic
engineering
Rat
Pigs
Wolf
Horse
Cloning for
food
Rabbit
Sheep
Water Buffalo
Genetically Engineered Cloning
• Remove the haploid nucleus from an ova
& the diploid nucleus from a somatic cell
•Insert the diploid nucleus into the
donor ova
•Now we have a
diploid ova (zygote)
Rapid mitosis will occur!!
What is Asexual Reproduction?
A new organism (sometimes
more than one new organism)
is produced from one
organism.
• Only one parent is
needed to reproduce
asexually.
• In most cases:
Mitosis is the
only type of cell
division involved
With Asexual Reproduction…..
The new organism will have
hereditary material identical to
the hereditary material of the
parent organism.
Offspring are
genetically identical to parent
So, what is the difference between
asexual and sexual reproduction?
Asexual
Reproduction:
Sexual
Reproduction:
• Reproducing without the
interaction of 2 sexes, one parent
needed.
• The make up of offspring is
genetically IDENTICAL to the
parent.
• Cell division process:
MITOSIS
• Fusion of 2 gametes (sperm
and egg).
• The make up of offspring is
genetically similar, different
genes though.
• Cell division process:
MEIOSIS
Assessment:
Read textbook page 250-252.
Complete “Reading Check”
on page 251 & 252
What are the 6 different types
of Asexual Reproduction?
1.Binary Fission
2.Budding
3.Sporulation
4.Regeneration
5.Rhizomes
6.Tubers
1. Binary Fission
•
•
Organism splits into two equal halves
Most common method of reproduction
in unicellular organisms (BACTERIA)
2. Budding
• offspring grows from a
“bud” on surface of
larger parent
• will eventually break off
and
live
independently
• occurs in: yeast, hydra
(small animal) and
many plants
• Budding vs. Binary
Fission?
• budding divides living
material unevenly
3. Sporulation
-spores are released in large numbers
and are carried by wind or water
-can survive conditions that kill off
parent
- produced by many plants and fungi
(molds & mushrooms)
4. Regeneration
-ability to replace missing
body parts
-occurs in all organisms to
some degree
- can only produce new
organisms in simpler
species
5. Rhizomes
-underground stems
produced by plants
- As these stems grow
through the soil, they
produce more roots which
develop into plants
6. Tubers
- Modified rhizomes
- Start out as a bud or eye on
potatoes
-Develop into root and
then adult
Examples: potatoe
Asexual Reproduction vs. Sexual Reproduction
Let’s record the differences between these 2 types of reproduction:
Asexual
Reproduction
Cell Division
Offspring
# of parents
Genetic make-up
(Heredity)
Type of Organisms to
Undergo This Type
of Reproduction
Sexual
Reproduction