Organize the following DNA terms in
order of size, from largest to smallest
Gene
Codon
Chromosome
Nucleotide
Genome
Mitosis and Cancer
Study Guide
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Describe the roles of cell division in living organisms.
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Compare the cellular processes and cellular products of asexual and sexual
reproduction.
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Describe the basic structure of a chromosome, and explain how chromosomes are
duplicated.
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Describe the key events of each phase of the cell cycle.
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Describe the key events of each phase of mitosis.
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Compare the processes of cytokinesis in animal and plant cells.
•
Describe how the cell cycle control system normally functions and explain the
consequences of errors in this system.
Explain how cancer cells are different from normal cells of the body.
Explain how you can reduce your risks of developing cancer.
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Each of us began as a single cell,
so one important question is:
How did that single cell develop into
the present trillions of cells in our body?
Zygote (one cell)
Multicellular person
Two types of Cell Division
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Two types of Cell Division
Mitosis: one cell  two daughter cells (genetically identical to parent cell )
takes place in somatic cells for:
growth of organism
replacement of dead cells
repair of injured tissue
Cancer
Meiosis:
one cell  four daughter cells (NOT genetically identical to parent cell)
takes place in sex organs for:
production of gametes (sperm or egg)
Down Syndrome
Before a cell divides, what does it need to do?
Grows in size and Copies its DNA
so that enough cell materials
can be split between daughter cells
3
The Cell Cycle is the life of a cell
from its birth to its division
Interphase
G1: cell growth
S phase: Chromosomes are copied
by DNA replication
G 2: cell growth
Cell division phase
Two overlapping steps:
Mitosis: DNA (chromosomes)
distributed in to two nuclei
Cytokinesis: cytoplasm divides in two
What controls the cell’s cycle?
External and internal signals (molecules)
tell the cell whether to divide or not
These signals activate certain genes
The proteins produced will
Promote cell division
Inhibit cell division
What will the result if one of these genes
Has a mutation?
4
Genes associated with cancer
Proto-oncogenes:
normal: stimulate cell division
mutated: uncontrollable cell division
Tumor suppressor genes:
normal: inhibit cell division
mutated: does not inhibit cell division
These genes normally are able to control
the cell division
but when mutated
they lead to uncontrollable cell division
What are the disadvantages of
patenting cancer genes?
Cancer results after multiple mutations
in the same line of cells
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Carcinogens
cause mutations on the DNA that lead to cancer
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S phase
Process: DNA replication animation
Both strands are used as template
Semi conservative process:
each new molecule of DNA
has an old strand and a new strand
Who is involved?
old DNA
DNA polymerase
individual nucleotides
Accuracy: 1 error/billion  name for the error?
why are these errors important?
In what part of the cell does DNA replication take place?
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Cell showing chromosomes
How many chromosomes
after the S phase
does this cell have?
Chromosome
Centromere
Sister chromatids
Mitotic Phase:
Mitosis and Cytokinesis
Purpose:
create two daughter cells identical to mother cell
Separate chromatids so that each new cell
gets a copy of all the chromosomes
Method: a dance of chromosomes
dance directors: two centrosomes
Footstep guides: microtubules
(form mitotic spindle)
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Mitosis phases:
Interphase
technically not part of mitosis
Chromosomes (DNA) as chromatin
Animation
Prophase: Preparation
Metaphase: Middle
Anaphase: Apart
Telophase-Cytokinesis:
Two nuclei (telophase)
Cut cytoplasm (cytokinesis)
Mitosis Table
STAGES
What happens to the
Chromosomes?
Other Cellular details
G2 of interphase
Prophase
Metaphase
Anaphase
Telophase
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Cytokinesis varies
in animals cells and in plants cells
by Cleavage Furrow
by Cell Plate
Why do cells divide by mitosis?
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