Download Mitosis and Cell Differentiation

9/6/2015
Mitosis and Cell Differentiation
DNA is stored in the Nucleus
Genome: total DNA in a cell (individual)
Each chromosome is a single DNA
Number of chromosomes
varies for each species
Ant has 2
Human has ____
Turkey 82
A DNA molecule has sections
that code for a protein
called Genes
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Organize the following DNA terms in order of size,
from largest to smallest
Gene
Codon
Chromosome
Nucleotide
Genome
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
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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
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
Mitotic phase
Two overlapping steps:
Mitosis: DNA (chromosomes)
distributed in to two nuclei
Cytokinesis: cytoplasm divides in two
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How is cell cycle regulated?
The expression of different genes directs
the progression of a cell through the cell cycle
Proto-oncogenes:
normal: stimulate cell division
Tumor suppressor genes:
normal: inhibit cell division
These genes normally are able to control
the cell division
but when mutated
they lead to uncontrollable cell division
Cancer results after multiple mutations in
the same line of cells
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S phase: DNA synthesis
Process: DNA replication animation
In what part of the cell does replication take place?
Accuracy: 1 error/billion  name for the error?
why are these errors important?
Carcinogens
cause mutations on the DNA that lead to cancer
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Mutations are the source of life’s diversity
Mitotic phase
Mitosis:
produces 2 nuclei
that are identical to original nuclei
Prophase: chromosomes condense
Metaphase: chromosomes line up in the middle
Anaphase: chromosomes are pulled apart
Telophase: membranes form
Cytokinesis:
Cytoplasm is divided in two
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Why do cells divide by mitosis?
A pancreas cell, eye cell and nerve cell in your body:
Are these cells genetically identically to each other
(same chromosomes) ?
Does a eye cell have the gene to make insulin?
Why are they different in form and function?
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Most cells in an adult body are differentiated
Differentiated cells are specialized in form and function
Differentiated cells have a particular
pattern of genes that are expressed
and not expressed
How do cells become specialized?
Cell differentiation occurs during
the embryo development
Early cells are not differentiated
Aka Stem Cells
during development (mitosis)
become more specialized
(differentiated)
by getting some genes activated and
some others inactivated
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Stem cells have different levels of “stemness”
Why is studying stem cells useful?
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Stem Cell Therapy:
embryonic stem cells vs. adults stem cells
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