Biology 11 Advanced

Introductory LetterWhat Is Life?A Case Study

Introductory Letter - Just send me a short letter via email and tell me a little bit about yourself. It’s a nice way for me to get to know you, and gives you the chance to tell me anything important you feel I should know, that will help you with your success in this class. My email is amanda.dalby@msvu.ca

So, about me. I’m from a small town on the south shore of Nova Scotia called Liverpool. I have a brother and a sister, two nieces and one nephew. I did my undergrad at Dalhousie University with a major in biology and two minors in psychology and history. I work part time at the Canada Games Centre, as well as tutoring.

Maybe include things such as:•Your family•Your interests•Your job (if you have one)•Your goals for the class and any plans for after graduation•How you learn best (what learning style and assessment do you like the best?)•What you hope to learn from the biology 11 advanced class•Anything else you feel I should know

What Is Life? A Case Study

Read the following slides and answer the following questions. Submit your answers to me via email by the end of the day on Thursday. I will accept it up until the end of the day Friday.

Life – The Final Frontier

A Case Study on the Characteristics of Life

Adapted from William Rogers (Ball State University) and Thomas Horvath (SUNY – Oneonta)

Question 1 – Do you think life exists elsewhere in the universe besides on planet Earth?

The Scenario

The Prime Minister of Canada is under extreme pressure from both the House of Commons and the

public to balance the budget. Space exploration is one area that seems to be mentioned for budget

cuts.

The Prime Minister is fully aware that there is a risk, albeit small, that if life forms from outer space enter the Earth’s biosphere, the ecological

and pathological consequences could be devastating.

Because of this, the Prime Minister does not want to cut funding for the space program.

Your Task

Your job, as a chief advisor to the Prime Minister, is to make a recommendation based on the

following study.

The Prime Minister wants to know if an announcement should be made that extraterrestrial

life has been discovered.

NASA Information

NASA has a Planetary Protection Policy that is designed to protect planets, moons, asteroids, etc., from contamination by Earth life, and protecting Earth from possible life forms from other solar system bodies. The Policy protects planets from living organisms, not fossil or chemical evidence of life.

One of NASA’s goals is to determine the characteristics of living organisms.[1]

How will NASA determine if what it finds is evidence of life or is something that is actually alive?

1 http://exobiology.nasa.gov/ssx/exobiology.html

So What Are The Basic Characteristics Of Life?

Are any of the following alive? Do they exhibit characteristics of life?

Think About It

Why do space programs like NASA look for evidence of water on Mars?

A)Martian life requires water.B)The polarity of water is necessary for making DNA. C)Earth life requires water. D)Organic molecules can be dissolved in water.

The NASA Planetary Protection Team has been given a chunk of subterranean ice collected on Mars by one of the rovers. The first task is to determine if the ice contains evidence of life.

Initial scans of the ice reveal bacteria-like nanoparticles (100 nm or smaller) that contain DNA.

How do you determine if the nanoparticles are alive?

A)Thaw the ice and see if they are mobile.B)Thaw the ice and see if they grow and reproduce.C)Keep it frozen and run tests to determine more about their chemical composition.D)Thaw the ice and expose them to an electrical charge and look for a response.

Results from Nanoparticle Scans

•Surrounded by cellular membrane –Composed of calcium phosphate rather than

phospholipids •No internal membrane-bound structures (organelles)

•Not mobile

•Small amounts of DNA and proteins

•Reproduction only in anoxic environment –Antibiotics prevent reproduction

Based on your answers to the previous questions, is there enough evidence to say that the nanoparticles are alive?

Why or why not? What characteristics did you come up with for living things?

Image Courtesy of the National Science

Foundation

Closer investigations reveal viruses attached to some nanoparticles.

Virus – Structure and Replication

Virus – Structure and Replication

Results from Virus Scans

•Contain RNA and proteins.

•Not mobile.

•Only reproduce when nanoparticles are present. •Doesn’t use any type of food presented them.

Based on your list of characteristics of living things, is there enough evidence to say the virus objects are alive? Why or why not?

Would you confirm to the Prime Minister that extra-terrestrial life has been discovered? Why or why not?

Submit a short summary to me, essentially what your recommendation would be, by email, amanda.dalby@msvu.ca) with your answers to this case study as well as what your listed for characteristics of life.

To help you prepare better for our time in the lab, I would like you to find a diagram of a microscope, labeling the parts and the functions.

To help with this, you can complete the table on page 4 (question 3&4) in your textbook.

I will not be checking this, however, you will be responsible from now on for knowing the parts of the microscope and their functions; I won’t be answering these questions from now on.