Unit 1: Chapter 2: Energy Life and the Biosphere Flashcards
What is NASA’s definition of life?
Self sustained chemical system that is capable of undergoing Darwinian or Biological evolution
9 Characteristics of living organisms
1) Take in energy and materials and release waste
2) Chemical organized
3) Structurally complex
4) Have coded instructions (genetic info.)
5) Can sense and react to environmental changes
6) Grow and Develop
7) Reproduce
8) Communicate
9) Move (by themselves)
What is energy?
The capacity to do work
What is chemical energy?
The energy stored in organic molecules
What is free energy?
The portion of chem. energy available to do work after a chem. reaction
- Usable energy
3 things free energy can be used for
1) Chemical work- Synthesizing or breaking down large complex molecules
2) Mechanical work- Muscle contraction
3) Transport work- Moving or concentration raw materials or nutrients
Heterotrophs
Obtain energy from consuming other organisms
Autotrophs
Obtain energy from non-living sources
Ex: Plants (get energy from the sun)
Photoautotrophs
Use solar energy plus CO2 plus H2O to make organic compunds (photosynthisis)
Chemoautotrophs
Use energy from inorganic chemicals to store chemical energy in the form of organic compounds (chemosynthesis)
What do heterotrophs consume?
-Autotrophs and other heterotrophs
Where can all types of energy be traced back to
-The sun
Abiotic factors in an ecosystem
- Non-living factors
Ex: Soil, water, weather
Biotic factors in an ecosystem
- Living factors
Ex: Organisms
Food web (Figure 2.6)
- Producers to consumers (or decomposers)
- Consumers to other consumers (or decomposers)
- Consumers to decomposers
- Decomposers release chemicals into the soil for producers
What is the first law of thermodynamics?
- Energy cannot be created or destroyed but can change form
- Organisms must acquire energy from an outside source
- Digestion releases free energy
What is the law of conservation of energy?
The total energy in the universe is constant
What are endothermic (endergonic) reactions?
- Reactions the absorb energy; putting energy into the system
Ex: Photosynthesis
What are exothermic (endergonic) reactions?
- Reactions that release energy
Ex: combustion
What is the second law of thermodynamics?
- Systems tend to change in ways that increase disorder (“entropy”)
- Creating and maintaining order takes energy
Flow of energy in an ecosystem
- Heat is lost in every energy transfer
- Ultimately increasing the entropy of the universe
Catalysts in chemical reactions do what?
1) Chemicals that lower the activation energy of a chemical reaction
2) Change the rate of chemical reactions (amount of product/time)
What are enzymes?
- Catalysts in living organisms
- Mostly proteins, a few are RNA molecules (ribosome)
- Speed up reactions that would otherwise occur to slowly for life purposes
What is the active site?
- The part of the enzyme w/ a specific shape that’s directly involved in the catalysts
- The substrate goes in it
