Download Nucleus - Control Center of cell

Nucleus - Control
Center of cell
From DNA to Proteins
Nucleus - Control Center
Contains master set of
instructions for each
cell that determines:
• Function
• When/how it
grows/divides
• When it dies
DNA carries master set of
instructions for cell function
• Deoxyribonucleic acid
• Two stranded twisted ladder molecule in shape called a
“double helix”
• Sides of ladder made up of sugar and phosphate
• Steps of ladder made up of nitrogenous bases
– Adenine
– Guanine
– Thymine
– Cytosine
DNA Molecule
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Arrangement of bases in
DNA directs all cell activities
• DNA messages are
the result of how
bases are arranged
A joins with T
(American telephone)
G joins with C
(Canadian government)
• Order and number
differ. Some
molecules of DNA
can be several
millions base pairs in
length
Create your own DNA
• Assignment:
– Using materials to create 3-Dimensional
model of DNA
DNA is stored in Chromatin
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• Chromatin is a substance
that contains DNA and
proteins.
• each strand of chromatin
is one molecule of DNA in
the nucleus.
• During cell growth DNA
uncoils and creates
proteins.
• Chromatin coils into
Chromosomes (x shaped
structure) when cells
ready to divide
Relationship between
DNA-->Chromatin-->Chromosomes
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Every Organism has specific
number of chromosomes
• Humans have 46 (23
pairs one from each
parent)
• One pair determines
sex. XX or XY… why?
• Flies have 4
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• Compare the two
chromosome charts
Genes are found on
Chromosomes
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• Specific places on
Chromosomes
contain small
segments called
genes
• Store information to
produce 100,000
different proteins
• Arrangements of
bases in gene
produce a specific
protein.
Proteins determine what
cells will become
• Functions of cells
determined by
proteins created
by “reading”
genes.
• Proteins make a
cell specialized
(hair cell, skin cell,
sensory cell)
• Specialized proteins
called enzymes
speed up chemical
reactions in cells.
• Protein called
hormones spread
information
throughout body.
(example growth of
bones, puberty)
Creation of Proteins
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What’s next for scientists
• After human
genome project
– Must find out how
25,000 genes make
90,000 proteins.
– How can one gene
code for more
than one protein?
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