UNIT 2 - A 2.1 - Origin of Cells Flashcards
How old is Earth believed to be?
4.5 billion years old
How was Earth supposedly able to grow and temperatures on it rise?
There was no atmosphere so objects from space could hit Earth
What did carbon dioxide and methane allow, resulting in higher surface temperature?
UV light to penetrate the early atmosphere and retain heat
Why was there no ozone at the time?
Because free oxygen was not present
What were 7 of the possible components of Earth’s early atmosphere?
methane, ammonia, water vapor, carbon dioxide, hydrogen sulfide, hydrogen, nigrogen
What could have resulted in the spontaneous formation of many carbon compounds?
Earth’s early atmospheric components coupled with high surface temperatures and lightning, followed by gradual cooling
What are 7 functions of life?
Metabolism, growth, reproduction, response, homeostasis, nutrition, excretion
What is a result of metabolism?
Cells can convert one energy form to another
What does reproduction involve?
Hereditary molecules passed to offspring
What do organisms respond to which is essential for survival?
Stimuli
What does responding to stimuli allow organims to do?
Adapt to the environment
What does homeostasis refer to?
The maintenance of a constant internal environment (ex. temperature, acid-base levels)
What is the basis of nutrition?
Using a source of compounds with many chemical bonds that can be broken down to provide an organism with the energy necessary to maintain life
Why is excretion essential to life?
Because it allows chemical compounds which the organism can’t use/is toxic or harmful to be released from the organism’s system
What are the main principles of cell theory?
All organisms are made of one or more cells, cells are the smallest unit of life, all cells come from pre-existing cells
