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
The application of technology to
biological investigations

Very useful for areas such as genetics
and forensics

Chromosomes from a single cell are
isolated in a solution

A microscope is used to take a picture of
the chromosomes

The chromosomes can then be sorted
and counted to determine if there are
any abnormalities

What gender is this person?
What is different about this person’s
chromosomes?

Karyotypes can determine if a person
has an abnormal number of
chromosomes and the location of the
abnormality

Non disjunction mutations (monosomy
and trisomy) can result in Down
Syndrome, Kleinfelter’s Syndrome and
Turner’s Syndrome

A chart to track the inheritance of a trait
through a family

Symbols are used to indicate gender
and presence of a trait
female
=
male
=
= female non carrier
= male non carrier
= female that shows the
= male that shows
the trait
trait
= female carrier
= male carrier
Note: Carriers are not always listed as they are not identified by
phenotype

At times, either biologically or artificially,
it is useful to combine certain segments
of DNA from two organisms
A gene for fluorescence
from a jellyfish was
inserted into the DNA of
mice

Organisms that have a transplanted
segment of DNA
1. A desirable gene from an organism is
identified
2. Enzymes cut the DNA at the specific site
of the desirable gene to remove it
3. Enzymes cut the DNA of the other
organism to make a gap
4. The gene is transplanted into the gap in
the DNA
5. The DNA is sealed together

An enzyme to cut the DNA at a specific
location
The enzymes are
Named for the
Bacteria they were
Isolated from


Plasmid – the circular DNA found in a
bacterial cell
› Commonly used to harvest desirable genes

Vector - The cut fragment of DNA that
can be carried into the host cell
› Commonly comes from the plasmid

Restriction Enzymes cut DNA at
predictable locations

The DNA fragments can be used for:
› DNA Fingerprinting
› DNA Recombination

The process of identifying the sequence
of base pairs at certain locations on the
DNA for comparison to a known sample

For example: A sample of blood is
collected from a crime scene. If the
fragments of DNA from the sample
match the fragments from the suspect,
than he is most likely the criminal

The fragments of DNA that are produced
by a restriction enzyme are too small to
be seen with a microscope

Therefore, a method called ‘Gel
Electrophoresis’ was developed to
separate the fragments

DNA fragments are inserted into an agar
gel using a micropipette

Using electricity (DNA is negative!), DNA
fragments pass between the molecules
of agar

Larger particles move slower through the
agar than smaller particles

After 30 minutes, the small fragments will
have moved farther than the large
fragments

The position of the fragments can be
compared to determine a match

Video

Video (play :45 – 1:30)

Which two samples match?
None!

Polymerase – an enzyme involved in
attaching nucleotides to a DNA strand
during DNA replication

PCR – A process in which DNA strands
can be replicated

PCR is useful to replicate DNA strands for:
› Forensic Analysis
› Mummies
› Dinosaurs/Fossils
(Denaturing = to break
down by heat or pH)

Stage 1: Denaturation
DNA is heated to ~98º C for 20 seconds
 The heat disrupts the Hydrogen bonds
that holds the DNA strands together
 Results in two single strands of DNA

(Annealing = Attaching)

Stage 2: Annealing
DNA is lowered to ~65º C
 Primers attach to the single DNA strands


Stage 3: Extension
DNA raised again to ~80º C for optimum
enzyme activity
 A solution of free nitrogen bases is
added
 DNA polymerase matches the bases to
form a complementary strand of DNA


In the end, very small samples of DNA
can be greatly increased

More tests can be run on forensic
samples, dinosaur and mummy DNA can
be replicated so it can be tested
Karyotypes are pictures of chromosomes
that can be counted and sorted
 Pedigrees are charts of a trait through a
family tree
 Genes can be cut by restriction enzymes
and transplanted into new organisms


Gel Electrophoresis is a process of
passing DNA fragments through agar gel
to separate the fragments by size

PCR is a process of replicating DNA
strands using heat and nitrogen bases