Topic 1: DNA - The Code of Life
Deoxyribonucleic acid (DNA) is the molecule
that carries the genetic blueprint
for all living organisms.
,DNA is found in three main locations within a cell:
Nuclear DNA: Found inside the nucleus. It forms chromosomes and contains the
majority of the organism's genetic information.
Mitochondrial DNA (mtDNA): Found inside the mitochondria. Inherited exclusively
from the mother.
Chloroplast DNA: Found in the chloroplasts of plant cells.
, DNA is a polymer made up of monomers called nucleotides.
It is a double-stranded helix (looks like a twisted ladder).
Each nucleotide is made of three components:
A phosphate group.
A deoxyribose sugar molecule.
A nitrogenous base.
There are four nitrogenous bases in DNA, divided into two groups:
Purines: Adenine (A) and Guanine (G)
• Pyrimidines: Thymine (T) and Cytosine (C)
Complementary Base Pairing Rule: Adenine always pairs with Thymine (A=T)
≡
and Guanine always pairs with Cytosine (G C) via weak hydrogen bonds.
Deoxyribonucleic acid (DNA) is the molecule
that carries the genetic blueprint
for all living organisms.
,DNA is found in three main locations within a cell:
Nuclear DNA: Found inside the nucleus. It forms chromosomes and contains the
majority of the organism's genetic information.
Mitochondrial DNA (mtDNA): Found inside the mitochondria. Inherited exclusively
from the mother.
Chloroplast DNA: Found in the chloroplasts of plant cells.
, DNA is a polymer made up of monomers called nucleotides.
It is a double-stranded helix (looks like a twisted ladder).
Each nucleotide is made of three components:
A phosphate group.
A deoxyribose sugar molecule.
A nitrogenous base.
There are four nitrogenous bases in DNA, divided into two groups:
Purines: Adenine (A) and Guanine (G)
• Pyrimidines: Thymine (T) and Cytosine (C)
Complementary Base Pairing Rule: Adenine always pairs with Thymine (A=T)
≡
and Guanine always pairs with Cytosine (G C) via weak hydrogen bonds.
