Facts About Your DNA
Inside every cell in your body there is a nucleus that contains your genetic material. That genetic material is deoxyribonucleic acid – DNA for short.
Your DNA controls many of the things about you, but scientists still are not sure about the exact role of nature (your genes) and nurture (how you
were raised) in making you who and what you are.
Here are some facts:
• Almost every cell in your body contains about 2.91 billion DNA.
• The DNA is divided into two sets of 23 chromosomes.
• You get one set of chromosomes from your mother and one set from your father.
• Every time your cells divide, the information is copied and divided into the new cells. Every time those chromosomes are passed on from mother or
father, they are recombined to make unique chromosomes — YOUR chromosomes.
Nucleotides and the Structure of DNA
• Structurally, DNA is made up of nucleotides.
• A nucleotide is made up of a sugar, a phosphate and a base.
• Each nitrogenous base pair is held together by weak hydrogen bonds and stacked flat on top of each other like steps.
• To each base pair, a two sugar-one phosphate complex is attached. This formed the so-called nucleic acid.
• Nucleotides hook together to make the sugar-phosphate backbone of every strand of DNA.
• The bases pair up with opposite matching bases on the other strand of DNA that makes up the “double-helix” structure.
• The pairs are linked by weak hydrogen bonds.
• There are four kinds of nucleotides or “base pairs” -- A for adenine, T is for thyamine, G is for guanine and C is for cytosine. A always pairs with T.
G always pairs with C.
• They are linked together (the two strands of DNA) and stacked like a ladder who’s sides spiral around each other into their famous double helix
shape.
©Sheri Amsel • www.exploringnature.org
Collaborative consultation on genetics from Dr. Stephen M. Carleton, Assistant Professor,
Department of Anatomy and Cell Biology, SUNY Health Science Center at Brooklyn.
The Structure of DNA
1. Structurally, DNA is made up of nucleotides.
2. A nucleotide is made up of a sugar, a phosphate and a base.
Nucleotide
sugar+phosphate+base
3. Nucleotides hook together to make the sugar-phosphate backbone of every strand of DNA.
4. Bases pair up with opposite, matching bases on the other strand of DNA.
5. There are four kinds of base pairs made up of adenine (A), thyamine (T), guanine (G), cytosine
(C). A always pairs with T. G always pairs with C.
6. The two strands of DNA are linked together by weak hydrogen bonds and stacked like a ladder
who’s sides spiral around each other into their famous double-helix shape.
phosphate
sugar
base
sugar-phosphate backbo
ne
phosphate
sugar
c
g a
c
c
g
c t
t
g a
c t
double-helix shape of DNA
cytosine
guanine
weak
hydrogen
bonds
cytosine
base
pairs
adenine
thymine
guanine
©Sheri Amsel
www.exploringnature.org