What is the definition of life?
A self-sustaining chemical system capable of Darwinian evolution.
What are cells?
The basic units of life that contain DNA and perform life processes.
What are the key characteristics of life?
Extracts energy, maintains itself, modifies environment, reproduces, and evolves.
Why is carbon essential for life?
It forms long, stable chains and complex molecules capable of storing information.
The basic units of life that contain DNA and perform life processes.
Oxygen, carbon, hydrogen, and nitrogen.
What is DNA?
A molecule that stores genetic information in a double-helix structure using a sequence of bases.
What is RNA?
A molecule that carries genetic information from DNA and helps build proteins.
What is the relationship between DNA, RNA, and proteins?
DNA is transcribed into RNA, which is translated into proteins that perform cellular functions.
What are proteins?
Molecules that provide structure and act as enzymes to control chemical reactions in cells.
How many possible genetic codes exist and why?
64, because combinations of 3 bases from 4 possible bases create 64 codons.
What is mutation?
A change or copying error in DNA.
What is natural selection?
The process where organisms best adapted to their environment survive and reproduce.
What is biological evolution?
The gradual change in species over time through genetic variation and selection.
When and where did life first arise on Earth?
About 3.4 billion years ago in the oceans.
What are stromatolites?
Layered rock structures formed by early microbial life, providing evidence of early life.
What conditions are required for life to form?
Organic molecules, water, and a source of energy.
What is chemical evolution?
The process by which simple molecules combine to form more complex organic molecules.
What did the Miller–Urey experiment demonstrate?
That amino acids and organic molecules can form naturally under early Earth conditions.
What is the primordial soup hypothesis?
The idea that early Earth’s oceans contained organic molecules that led to life.
What is abiogenesis?
The origin of life from non-living matter.
What is the RNA world hypothesis?
The idea that RNA existed before DNA and could self-replicate.
What evidence supports panspermia?
Meteorites have been found to contain organic molecules like amino acids.
What is the Cambrian explosion?
A rapid increase in complex life forms about 540 million years ago.
What is panspermia?
The idea that life or organic molecules came to Earth from space.
