DNA
• DNA stands for
deoxyribonucleic acid.
• Genes are found on
chromosomes.
• Chromosomes are made
up of proteins and DNA.
• Gene material (DNA)
must supply instructions
for building cell
organelles and cell
processes.
• Gene material (DNA)
must copy each time cell
divides.
Nucleotides
• Nucleotides- sub units of DNA, made up of
sugar, phosphate and a base
• 4 bases are adenine, thymine, guanine, and
cytosine. Each have a different shape.
• Chargaff’s Rules – A = T, C = G
• Rosalind Franklin suggested DNA is a spiral
shape.
• Watson and Crick concluded that DNA is a
twisted ladder shape = double helix.
The double helix
• Sides of the ladder are
made up of alternating
sugar and phosphate
molecules.
• Rungs (steps) of the
ladder are the pair of
bases.
• One side of DNA can
copy itself easily, it splits
down the middle and
each side is used as a
template for the new side.
Function of DNA
• DNA directs every cell in
your body how and when
to synthesize proteins for
its activities and
development.
• Proteins determine
different shapes, sizes,
colors, etc.
• During cell division, the
DNA unzips and gives
each new cell a copy of
itself.
Uses of DNA
• Identifying criminals.
• Proving innocence
• Determining heredity
(family relationships)
• Treating illnesses
• Raising better crops
• Creating new
medicines
• Better livestock
Vocabulary
• Incomplete dominance – when one trait is not
completely dominant over the other, they both
appear in the phenotype.
• Mutations- a change in the order of the bases in
an organisms DNA.
• Mutagen – a physical or chemical agent that can
cause a mutation to occur in DNA.
• Pedigree – a diagram used by genetic
counselors to predict if hereditary material will
be passed to future generations.