PH 346 - Midterm 2 Exam With
Complete Solution
Transgenic organism - ANSWER An engineered organism where we put the DNA of one
organism into another.
C-elegans - ANSWER Invertebrate - 959 total cells in whole organism (hermaphrodite) in
adults
Male: 1031 cells
Only has 302 neurons. 131 cells die each time
Genome has been mapped- all genes identified
Transparent/translucent - watch cells behave
Is a good model to study events like cell death
Viktor Hamburger - ANSWER Major discovery: Cell death in normal embryonic
development: Programmed cell death is an active process that sculpts normal
development.
Discovery was in chick
Another major contribution: explored the earliest stages of embryonic motor behavior -
earliest movements do not require sensory input.
Toxicology - ANSWER Study of adverse effects of chemicals on biology/biological
systems
Effects range from skin damage/irritation to death
Natural origin chemicals = toxins - ANSWER Ex. cobra venom
Synthetically made bad chemical = toxicant - ANSWER BPA
Toxicity - ANSWER Can occur on many different levels
Population, body, organ, functional unit, cell, organelle, molecule
Cell death - ANSWER From worm to human it is the same
CED-9 is the key regulator in programmed cell death in c. elegans
Bcl2 (mammal) is "homologous" to CED-9 (worm)
, If you put human active Bcl2 gene in nematode - it prevents apoptosis
Apaf-1 is homologous to CED-4, if activated get apoptosis
Role of cell death and digit development - ANSWER BMP4 is a protein that can cause
cell death
Gremlin is a protein that can inhibit BMP's
If BMP4 is down, you will get webbed digits
Pages 404-405 in the main book (Gilbert and Epel)
Basic tenant of toxicology - ANSWER All substances have the potential to be toxic
Paracelsus - ANSWER Father of toxicology
Said: "dose makes the poison"
Dose response - ANSWER Correlation between the amount of a drug given and its
effects
Exposure routes (adult): dermal, oral, inhalation
Other routes include through cuts in the skin and the eyes
For fetal exposure: placenta is the exposure route
Toxicant classifications - ANSWER Based on: chemical class, source of exposure and
organ system effected
Toxicokinetics - ANSWER The area of study on how a chemical substance enters the
body and the course it takes while in the body
BPA - ANSWER Found in: epoxy resins, and reusable water bottles (but no more)
Exposure: oral, inhalation
Oral: via leaching from metal food cans
Low dose exposure is the concern!!
LD50 - ANSWER The amount of a chemical that kills 50% of the animals in a test
population.
Pufferfish - ANSWER Second deadliest vertebrate on Earth. Tetrodotoxin( ttx) binds to
and blocks sodium channels (Na+) from opening.
Considered a rare delicacy in Japan
There is enough of the powerful toxin in one pufferfish to kill 30 adult humans, and there
is no known antidote.
Complete Solution
Transgenic organism - ANSWER An engineered organism where we put the DNA of one
organism into another.
C-elegans - ANSWER Invertebrate - 959 total cells in whole organism (hermaphrodite) in
adults
Male: 1031 cells
Only has 302 neurons. 131 cells die each time
Genome has been mapped- all genes identified
Transparent/translucent - watch cells behave
Is a good model to study events like cell death
Viktor Hamburger - ANSWER Major discovery: Cell death in normal embryonic
development: Programmed cell death is an active process that sculpts normal
development.
Discovery was in chick
Another major contribution: explored the earliest stages of embryonic motor behavior -
earliest movements do not require sensory input.
Toxicology - ANSWER Study of adverse effects of chemicals on biology/biological
systems
Effects range from skin damage/irritation to death
Natural origin chemicals = toxins - ANSWER Ex. cobra venom
Synthetically made bad chemical = toxicant - ANSWER BPA
Toxicity - ANSWER Can occur on many different levels
Population, body, organ, functional unit, cell, organelle, molecule
Cell death - ANSWER From worm to human it is the same
CED-9 is the key regulator in programmed cell death in c. elegans
Bcl2 (mammal) is "homologous" to CED-9 (worm)
, If you put human active Bcl2 gene in nematode - it prevents apoptosis
Apaf-1 is homologous to CED-4, if activated get apoptosis
Role of cell death and digit development - ANSWER BMP4 is a protein that can cause
cell death
Gremlin is a protein that can inhibit BMP's
If BMP4 is down, you will get webbed digits
Pages 404-405 in the main book (Gilbert and Epel)
Basic tenant of toxicology - ANSWER All substances have the potential to be toxic
Paracelsus - ANSWER Father of toxicology
Said: "dose makes the poison"
Dose response - ANSWER Correlation between the amount of a drug given and its
effects
Exposure routes (adult): dermal, oral, inhalation
Other routes include through cuts in the skin and the eyes
For fetal exposure: placenta is the exposure route
Toxicant classifications - ANSWER Based on: chemical class, source of exposure and
organ system effected
Toxicokinetics - ANSWER The area of study on how a chemical substance enters the
body and the course it takes while in the body
BPA - ANSWER Found in: epoxy resins, and reusable water bottles (but no more)
Exposure: oral, inhalation
Oral: via leaching from metal food cans
Low dose exposure is the concern!!
LD50 - ANSWER The amount of a chemical that kills 50% of the animals in a test
population.
Pufferfish - ANSWER Second deadliest vertebrate on Earth. Tetrodotoxin( ttx) binds to
and blocks sodium channels (Na+) from opening.
Considered a rare delicacy in Japan
There is enough of the powerful toxin in one pufferfish to kill 30 adult humans, and there
is no known antidote.
