dna

1. How DNA
Works

2. • DNA is found in
the cells of all
organisms, from
mosquitoes to
bacteria to humans
• Each organism has
a unique set of
DNA, but DNA
functions the same
way in all
organisms.

3. Unraveling DNA
• 1) DNA is often wound around proteins,
coiled into strands, and then bundled up
even more
• 2) In a cell that lacks a nucleus, each
strand of DNA forms a loose loop within
the cell
• 3) In a cell with a nucleus, the strands of
DNA and proteins: are bundled into
chromosomes

4. See the Difference!

5. • 4) The order of the bases on one side of
the molecule is a code that carries
information.
• 5) A gene consists of: a string of
nucleotides that gives cell information

7. Help From RNA
1) RNA: Ribonucleic acid,
a molecule that is
present in all living
cells and plays role in
protein productions
2) RNA is so similar to DNA
that it can serve as:
temporary copy of a
DNA segment.

8. Making of a
Protein (Figure 2):

10. Changes in Genes
Mutation: Changes in
the number, type, or
order of bases on a piece
of DNA
1) Deletion: base is
left out
2) Insertion: extra
base added
3) Substitution:
wrong base is
used

11. Do Mutations Matter?
• Three possible consequences to
changes in DNA:
1) An improved trait
2) No change
3) Harmful trait
• When an error is found, it is usually fixed
• If the mutation occurs in the sex cells, the
changed gene can be passed from one
generation to the next.

12. How Do Mutations Happen?
1) Mutations happen regularly because of:
random errors when DNA is copied
2) Also, damage to DNA can be caused by
abnormal things that happen to cells
3) Any physical or chemical agent that can
cause a mutation in DNA is called a
mutagen.
4) Examples of mutagens: X-rays, UV
radiation, cigarette smoke

13. Uses of Genetic Knowledge
• Genetic Engineering
1) Genetic engineering:
when scientists
manipulate individual
genes within an organism
2) New products created:
drugs, food, fabrics
3) For example, bacteria may
be used to make the
proteins found in a
spider’s silk
Genetically
engineered
peanut plant

14. • Genetic
Identification
1) Your DNA is
unique, so it can
be used like a
fingerprint to
identify you.
2) DNA fingerprinting
identifies: The
unique patterns in
an individual’s
DNA

15. 3) Identical twins have
truly identical DNA.
Scientists are now
able to create
something like a twin,
called a clone. A
clone is a new
organism that has an
exact copy of another
organism’s genes.