Respiration Case Study
The Case
You are working at the Forensic Science Laboratory in the
Phoenix Park. It has been a typical Dublin day with one fatality
which you have just completed a report on. You are about to
finish for the day when you get a call from your secretary. A
dead child has been brought in and an autopsy is needed
straight away. Foul play is suspected.
You head to the morgue. You are not looking forward to this
job but as a Forensic scientist this is all in a days work.
On arrival to the morgue you are given two reports, one from
the hospital and one from the Garda.
Hospital Statement
In the early morning the mother noticed her
daughter was not well. She was vomiting and
feeling very tired. The child went to bed and after
a short while the mother noticed that the child
had difficulty in breathing. She tried to wake her
daughter but was unable to do so. The child had
slipped into a coma. Three hours later the child
was admitted to the hospital. She had no
heartbeat and was not breathing.
Garda Report
On investigation it emerged that the child had
been giving her dog a bath. She had used a product
called Dogdays. On studying the contents of
Dogdays it was found to contain only natural
products and had been approved for external use
on animals.
Label from a bottle of Dogdays Flea Dip.
Dogdays Directions:
Dilute and mix thoroughly as follows. 2 cups warm water with 2 tsp of Dogdays
Using a sponge, drench hair completely with mixture. Avoid eyes! Massage into
skin and work up lather for 5-10 minutes. Then rinse off with tepid water.
Repeat every two weeks.
Ingredients:
Coconut oil, shampoo, oils of: orange, cedarwood, citronella, eucalyptus, bay,
rotenone (2%).*
* Rotenone
Rotenone* is a naturally occurring chemical with insecticidal, acaricidal (mite and
spider-killing) and piscicidal (fish-killing) properties, obtained from the roots of
several tropical and subtropical plant species belonging to the genus
Lonchocarpus or Derris. It is a selective, non-specific insecticide, used in home
gardens for insect control, for lice and tick control on pets, and for fish
eradications as part of water body management. Both a contact and stomach
poison to insects, it kills them slowly, but causes them to stop their feeding
almost immediately. It exerts its toxic action by acting as a general inhibitor of
cellular respiration
Autopsy Report
 The girl died within four hours of first vomiting
 Immediate cause of death was asphyxia (severely
deficient supply of oxygen to body)
 Tissue sections from the kidneys, lungs, thymus and heart
show massive cell death.
 ATP levels in the mitochondria of the heart cells were
shown to be reduced, however ATP levels in the
cytoplasm of these cells were found to be normal.
 Acetyl-coenzyme A levels were also found to be normal.
Student Questions
Part A : The Dip
1. Refer to the ingredients label. Suggest which ingredient may have
killed the girl?
2. How could a product, which is normally harmless to humans and pets?
have killed the girl?
Part B : Autopsy Report
1. Given the autopsy report and recalling your knowledge of cellular
biology, which organs, organelle and functions were disrupted by
Dogdays?
Part C : ATP Analysis
1. What specific part(s) of respiration was affected by the dip?
Part D : Subcellular Analysis
1. Would artificial respiration save the girl? Explain your answer
Part E : General Links
Based on your knowledge of Biology answer the following questions.
1. Give the function of the 4 parts of the body (organs/gland) which were
affected by Dogdays.
2. Explain the effects of asphyxia on the human body
3. ATP is an abbreviation. What does it stand for. Explain briefly the
role of ATP in the energy exchanges of a cell.
Teacher Material Only
Answers to Questions
Part A
1. The Rotenone killed the girl... Students will be expected to know
this after reading the handout.
2. There are a number of possible answers to this question.

She may not have followed directions and used too much of
the product.

During the washing she was exposed to the fumes and
inhaled large quantities of the chemical. The chemical if
inhaled would be quickly dispersed around the body due to
the large surface area of the lungs and the rapid diffusion
of the gas into the blood stream.

Age. Levels of a chemical which are safe for an adult may not
be safe for a child.
Part B
1. Organ
Kidneys, lungs, thymus gland and heart.
Organelle
Mitochondrion
Cell functions
Respiration
Part C
1. Krebs Cycle and the Electron Transport Chain are interrupted.
Glycolysis is working normally. This is indicated by the presence of
normal levels of acetyl co enzyme A
Part D
1. Probably not. Rotenone affects Kreb’s cycle and/or the electron
transport chain, therefore adding oxygen to the body will not solve
the problem. This questions deals with the misconception that
respiration and cellular respiration are the same thing.
Part E
1.
Kidneys
Lungs
Thymus gland
Heart
Excretion, osmoregulation
Excretion,respiration
Maturation of T Lymphocytes
Pumps blood
2. Students would be expected to know the function and necessity for
oxygen in the body. References should be made to the following



Gaseous exchange
Energy production
Cellular respiration
3. This is from the 2004 higher paper ( Q11a) worth 9marks.
ATP = Adenosine triphosphate (3m)
Role = P-P bond / holds or stores energy / passes on or releases
energy OR ATP………….ADP + P / + energy
(any 2 x 3m)