Download Dna - Quia

http://gslc.genetics.utah.edu/u
nits/basics/tour/
Introduction to Dna and genes
To do
• How do ear cells know their function is to
support hearing and not something else ?
• Ear cells have DNA that codes for hearing
http://gslc.genetics.utah.edu/units/basics/tour/
DNA
• DNA stands for Deoxy ribonucleic acid
DNA Structure
• DNA molecule comes in the form of a
twisted ladder or a spiral staircase
• Scientist call it the double helix
Function of DNA
• DNA Encodes a special detailed plan for
the functions and building of a cell.
Structure of DNA
•
The 2 sides of the ladder are made of
1. molecules of sugar called deoxyribose
2. Phosphate molecules that alternate with
sugar
Structure of DNA[ nitrogen bases ]
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•
1.
2.
3.
4.
Each rung of the ladder is made up of a
pair of molecules Known as nitrogen
bases
There are 4 kinds of nitrogen bases
Adenine {A}
thymine {T}
Guanine {G}
Cytosine {C}
Pairing of bases
• A -T
• And C –G
• The corresponding bases are held
together by chemical glue called
Hydrogen bonds
To do
• Suppose one strand of DNA contained the
following bases
• ACTGTCTG
• What would be the bases on the
corresponding strand of DNA ?
• TGACAGAC
• What structures make the sides of the
double helix ladder ?
• Sugar and phosphate
Strand of DNA
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•
•
•
•
•
•
A strand of DNA is made up of letters
ATGCTCGATCTAGAGC
The letters make words
ATG CTC ATC TAG AGC
The words make sentences
<ATG CTC ATC TAG AGC>
These sentences are called genes
Dna INTERACTIVE MODEL
• http://gslc.genetics.utah.edu/units/basics/b
uilddna/
• Why must a DNA of a cell replicate ?
• DNA needs to replicate to provide a
genetic code for the new cells produced
during mitosis
Dna REPLICATION
• http://www.biolessons.com/lessonplans/D
NAandprotein/websites/index.htm
• http://www.biolessons.com/lessonplans/D
http://www.ncc.gmu.edu/dna/repanim.htm
NAandprotein/websites/index.htm
DNA REPLICATION
• 2 sides of the molecule unwind and
separate
• The DNA molecule unzips
• Nitrogen bases that are floating in the
nucleus pair up
• Pairing of bases follows a definite rule
• A-T
• G-C
Homework
1. What does DNA stand for?
• DNA stands for Deoxy ribonucleic acid
2. What is the function of DNA?
• DNA Encodes a special detailed plan
for the functions and building of a cell.
3. What is the shape of DNA?
DNA molecule comes in the
form of a twisted ladder or a
spiral staircase
Scientist call it the double helix
•
What to molecules make up the sides of
the ladder?
• The 2 sides of the ladder are made of
1. molecules of sugar called deoxyribose
2. Phosphate molecules that alternate with
sugar
• What are nitrogen bases, What part of the DNA ladder
do they make up?
• Each rung of the ladder is made up of a pair of
molecules Known as nitrogen bases
• There are 4 kinds of nitrogen bases
1. Adenine {A}
2. thymine {T}
3. Guanine {G}
4. Cytosine {C
• Name and write the short forms of the four nitrogen
bases?
• Name and write the short forms of the four
nitrogen bases?
There are 4 kinds of
nitrogen bases
Adenine {A}
thymine {T}
Guanine {G}
Cytosine {C
• How do nitrogen bases pair?
• Adenine with thyamine
• Cytosine with gunanine
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•
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Write the corresponding bases for the
following DNA Strand
ATGCTCAGT
_TACAGTCA______________________
________________________________
____________________
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Explain what genes are made up of?
_GENES ARE MADE UP OF DNA
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State the steps for DNA replication?
DNA UNWINDS ,THE STRANDS SEPARATE,
CORRESPONDING NITROGEN BASES PAIR
WITH THE ORIGINAL DNA STRAND
What is the importance of DNA replication ?
DNA replication is required in duplication of
cells
•
•
forms the
side of the
ladder
and is a
sugar
Dexoribose
DNA
forms the
sides of the
ladder and is
Nitrogen
Bases
Symbol T
Pairs with
Thymine
Pairs with Symbol G
Guanine
Cytosine
Thyamine
Adenine
Gunanine
Phosphate
Nucleus
contains rod like
structures called
chromosomes
these rod like
structures are made
up of
DNA
DNA makes up
Genes
these structutes
pass characteristics
like hair and eye
color and these
characteristics are
called
Traits