Unit 1: Chapter 2: Energy Life and the Biosphere Flashcards

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1
Q

What is NASA’s definition of life?

A

Self sustained chemical system that is capable of undergoing Darwinian or Biological evolution

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2
Q

9 Characteristics of living organisms

A

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)

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3
Q

What is energy?

A

The capacity to do work

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4
Q

What is chemical energy?

A

The energy stored in organic molecules

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5
Q

What is free energy?

A

The portion of chem. energy available to do work after a chem. reaction
- Usable energy

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6
Q

3 things free energy can be used for

A

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

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7
Q

Heterotrophs

A

Obtain energy from consuming other organisms

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8
Q

Autotrophs

A

Obtain energy from non-living sources

Ex: Plants (get energy from the sun)

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9
Q

Photoautotrophs

A

Use solar energy plus CO2 plus H2O to make organic compunds (photosynthisis)

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10
Q

Chemoautotrophs

A

Use energy from inorganic chemicals to store chemical energy in the form of organic compounds (chemosynthesis)

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11
Q

What do heterotrophs consume?

A

-Autotrophs and other heterotrophs

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12
Q

Where can all types of energy be traced back to

A

-The sun

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13
Q

Abiotic factors in an ecosystem

A
  • Non-living factors

Ex: Soil, water, weather

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14
Q

Biotic factors in an ecosystem

A
  • Living factors

Ex: Organisms

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15
Q

Food web (Figure 2.6)

A
  • Producers to consumers (or decomposers)
  • Consumers to other consumers (or decomposers)
  • Consumers to decomposers
  • Decomposers release chemicals into the soil for producers
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16
Q

What is the first law of thermodynamics?

A
  • Energy cannot be created or destroyed but can change form
  • Organisms must acquire energy from an outside source
  • Digestion releases free energy
17
Q

What is the law of conservation of energy?

A

The total energy in the universe is constant

18
Q

What are endothermic (endergonic) reactions?

A
  • Reactions the absorb energy; putting energy into the system
    Ex: Photosynthesis
19
Q

What are exothermic (endergonic) reactions?

A
  • Reactions that release energy

Ex: combustion

20
Q

What is the second law of thermodynamics?

A
  • Systems tend to change in ways that increase disorder (“entropy”)
  • Creating and maintaining order takes energy
21
Q

Flow of energy in an ecosystem

A
  • Heat is lost in every energy transfer

- Ultimately increasing the entropy of the universe

22
Q

Catalysts in chemical reactions do what?

A

1) Chemicals that lower the activation energy of a chemical reaction
2) Change the rate of chemical reactions (amount of product/time)

23
Q

What are enzymes?

A
  • Catalysts in living organisms
  • Mostly proteins, a few are RNA molecules (ribosome)
  • Speed up reactions that would otherwise occur to slowly for life purposes
24
Q

What is the active site?

A
  • The part of the enzyme w/ a specific shape that’s directly involved in the catalysts
  • The substrate goes in it
25
Q

What is the substrate?

A
  • A starting molecule that bonds to the enzyme’s active site (fits in)
26
Q

Describe the induced-fit model of enzyme catalysis (lock and key model)

A
  • Enzymes bind substrates in their active site and bring them close together so they can react (this lowers the activation energy)
27
Q

Competitive inhibitors

A

Molecules that compete w/ the substrate for the active site (thus preventing the enzyme from catalyzing the reaction)

28
Q

Non competitive inhibitors

A

Bind w/ the enzyme away from the active site but cause the enzyme to change shape so that the substrate cant bind

29
Q

Explain the chemical equilibrium

A
  • Enzymes speed up chem. rxns. in both ways
  • Net direction depends on the concentration of reactants and products
  • Enzymes don´t change the chem. equilibrium of a rxn. but do speed up the rate at
    which its reached
30
Q

Effect of temp. and pH in enzymes

A
  • Enzymes have optimal pH and temp. ranges
  • At high temps. enzymes denature (loss their shape)
  • If they lose their shape they no longer work
31
Q

What is metabolism?

A

Sum of all chem. changes occurring in an organism

32
Q

What is synthesis

A

Building up

33
Q

What is decomposition

A

Breaking down and energy release (free energy is released)

34
Q

Explain Oxidation and reduction

A
  • The release of free energy from stored chems. almost always involves chem. oxidation (loss of electrons).
  • These electrons are donated to another molecule in the proses of reduction. For biological systems, oxidation and reduction usually involves hydrogen transfer as well
35
Q

What is physical digestion?

A

The breaking down of large pieces of food into small pieces of food by grinding or chewing

36
Q

What is chem. digestion?

A

The converting of large molecules into smaller ones by breaking chem. bonds

37
Q

Extracellular digestion

A

Digestion occurring outside the cell

Ex: The human digestive tract

38
Q

Intracellular digestion

A

Digestion occurs inside cells

Ex: Plants- The plants cells break down the food that the plant makes