PART I:THE VIKING EVIDENCE Over the past several decades, NASA has heen sending
ID: 69713 • Letter: P
Question
PART I:THE VIKING EVIDENCE Over the past several decades, NASA has heen sending mnts In 19761 bgf these solar system, and to assess the habitability of nearby pn-based c Th Marby planeter space to explore our gical or biological sources. What if these s been sending missions into outer space to explore our y of nearby planets. In 1976, the NASA Viking Mars organic compounds could have come from The lande discover life oave come from non citbon-based chemical building blocks. These rs can perform several small scale experiments on th nret the Mars Mars landers di discover life on Mars? Would we be able to recogni t as life? isolated specimen ize it as the results on results and d Analyze on page 1 of your handout. In your small groups you raw your own conclusions. conclusions. Experiment 1: White-film production The lander inoculat noculated several sterile culture dishes with Martian soil. A white-film soon formed off on the surface of each culture dish. The white-film resembles a dry crusi-film quickly coats crust and can be ser and transferred into a new sterile culture dish. Once transferred, the the new dish. white-film quickly coats Note: Microorganisms are capable of depositing crystalline duced by the specimens structures similar to those pro- Experiment 2: Heat Resistance The specimens were exposed to a variety of stress tests. Extreme temperature shifts (between -60C to 20C) had little to no impact on growth rate (white-film production). However, extreme heat (above the temperature ranges found on the surface of Mars) significantly inhibited growth. Experiment 3: Radiation Radiation exposure caused specimen growth to completely cease. Experiment 4: Appearance Under the microscope, specimens appear round (coccoidl in shape, with an average diameter be- tween 0.2-0.5 mm. (c) Transmission eledtron the specimen particles observed in thin microscopy sections of white-fim material (b) Transmission electron microscopy of of stained white-5m matenal showing smal coccoid shapped particles (O2) (a) Scanning electron microscope of white-flim materialExplanation / Answer
White film production - This is one of the characteristics of living things to grow and spread.
Gamma radiation - usually microbes are killed by radiation. This is also seen in a living organism.
Microscopic appearance- Bacteria -like shape. This shape is seen in living cocci.
DNA staining - The organism can have a DNA which does not bind to ethidium bromide.
DNA presence - The absence of any absorption at 260 nm wavelength does not rule out the presence of DNA. There could be other types of DNA which do no absorb at 260nm.
Protein presence - The protein in the organism may not bind to coomassie blue.
The impelling evidence is that the organism is living on the basis that it can grow and its growth can also be inhibited. Growth would not be possible if the organism was not viable. Hence, we can say that the DNA and protein in MArs organisms are different from those on earth.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.