fourteenth paper Flashcards
(26 cards)
3 necessities for life
1) nutrient source
2) energy
3) liquid water
life on earth is ____ based
carbon
DNA molecules resemble a _____
ladder
DNA guides ______ to form proteins
amino acids
what do proteins serve in the cell?
the cells basic structural molecules
define mutants
offspring born with random alterations in their DNA
the process of natural selection helps us ____
evolve
is natural selection random?
No
when did life arise on earth?
3.85 billion years ago
What does the Miller-Urey experiment show us?
the building blocks for life form easily under the conditions of the early earth
where did the first complex molecules form?
the sea floor
what do interstellar molecular gas clouds contain?
many complex, organic molecules
what 5 heavy elements are crucial for life?
carbon, oxygen, nitrogen, iron, and potassium
stars produce heavy elements up to iron, heavier are produced by __ __
supernovas
what is interplanetary debris?
organic matter that is constantly raining down from on earth from space
the earth is composed of mostly what two elements?
iron and oxygen
what is the Drake equation?
an equation to estimate the number of civilizations currently communicating in our galaxy
what are extremophiles?
microorganisms (viruses)
where do extremophiles live?
in unusual living environments (toxic, radiation, pressure)
what makes life possible on the deep sea floor?
hydrothermal vents
saturns moon titan is rich in __ ___
organic molecules
saturns moon Enceladus has ____ ____
liquid water
5 characteristics of life
1) organization
2) energy use and metabolism
3) maintanence of internal constant
4) reproduction, growth, development
5) irritability and adaptation
how many carbon compounds are on earth?
90 million
