Transcript DNA Helix Strand

DNA stands for:
D: Deoxyribo(se)
N: Nucleic
A: Acid
DNA is too
small to see,
but under a
microscope it
looks like a
twisted up
ladder or
double helix!
Every living thing has DNA. That means
that you have something in common with a
zebra, a tree, a mushroom and a beetle!!!!
•
•
Chromosomes are
composed of Genes.
Gene-which is a
segment of DNA that
codes for a particular
protein which in turn
codes for a trait.
•
Hence you hear it
commonly referred to as
the gene for brown hair
or the gene for blue
eyes.
http://www.youtube.com/wat
ch?v=qy8dk5iS1f0
IS SHORT FOR: Deoxyribonucleic
acid
FUNCTION: Carries information from
one generation to the next and
determines what you traits you will
inherit
LOCATION
• It is found in the nucleus of cells
(coiled up in the chromosomes)
DNA (cont.)
STRUCTURE
Shaped as a double helix (it looks
like a twisted ladder)
It is DOUBLE STRANDED
Has a deoxyribose sugar
Made out of repeating units
called nucleotides
**Draw a picture!
This is what a
nucleotide looks like
Each nucleotide contains:
Phosphate + Sugar + Nitrogen
base
DNA is just a bunch of
nucleotides put together!
The sugars and phosphates
make up the backbone of DNA
(the sides of the ladder).
The nitrogen bases make up the
rungs (steps of the ladder).
DNA (cont.)
Nitrogen Bases:
• A=Adenine
• T= Thymine
• C= Cytosine
• G= Guanine
Base pairs= bases have complementary pairs.
Adenine bonds to Thymine
Cytosine bonds to Guanine.
Make a saying to remember!!! APPLE TREES
COLLARD GREENS!!
•
Hydrogen bonds connect the N-bases together in the center.
sugar
phosphate
sugar
phosphate
sugar
phosphate
sugar
T
A
C
G
¦
¦
¦
¦
A
T
G
C
sugar
phosphate
sugar
phosphate
sugar
phosphate
sugar
...
...
All
DNA
All
DNA
All
DNA
(100%)
(100%)
(100%)
DNA
Quarter
All
DNA
Half
DNA?
(100%)
(50%)
DNA?
(25%)
Original cell
•
DNA Replication
Cell division
Daughter cells
Before a cell divides, it replicates all of the
DNA in the cell, thus its daughter cells have
the same amount of DNA as the original cell.
IS SHORT FOR: ribonucleic acid
FUNCTION: used to make a copy of
DNA because DNA is TOO BIG to be
taken out of the nucleus. It’s needed
for transcription and translation.
STRUCTURE:
Single-stranded
Has a ribose sugar instead of deoxyribose.
Nucleotides have a U (Uracil) instead of a
T (Thymine).
• DNA
makes an
exact copy of itself
using old strands as
a template to
make new strands.
Replication:
http://www.youtube.com/watch?v
=hfZ8o9D1tus
Replication:
http://www.youtube.com/watch?v
=hfZ8o9D1tus
Add new
nucleotides to
each parent strand
to make the
complementary
strands of DNA.
= forming two
completed strands
of DNA.