Assignment 1: Biology Article
voncolio
ch_4_-_energy_and_metabolism.pptxEnergy
Figure 4.5 Animated! Activation energy. Most reactions, including
energy-releasing ones such as burning wood cellulose, will not begin
without at least a small input of energy. This activation energy is shown
in the graph above as a bump in an energy hill. Reactants in this example
have more energy than the products. Activation energy keeps this and
other energy-releasing reactions from starting spontaneously.
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Potential Energy
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Kinetic Energy
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Thermodynamics
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Thermodynamics
Thermodynamics
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small molecules
(e.g., carbon dioxide, water)
energy-requiring reactions
organic compounds (carbohydrates, fats, proteins)
small molecules (e.g., carbon dioxide, water)
energy-releasing reactions
organic compounds (carbohydrates, fats, proteins)
A) Cells store energy in the chemical bonds of organic compounds.
B) Cells retrieve energy stored in the chemical bonds of organic compounds.
Figure 4.6 Cells store and retrieve energy in
the chemical bonds of organic molecules.
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Reactants:
2 H2 + O2
Activation energy
Difference between energy of
reactants and products
Products: 2H2O
Energy
Time
Activation Energy
Figure 4.5 Animated! Activation energy. Most reactions, including
energy-releasing ones such as burning wood cellulose, will not begin
without at least a small input of energy. This activation energy is shown
in the graph above as a bump in an energy hill. Reactants in this example
have more energy than the products. Activation energy keeps this and
other energy-releasing reactions from starting spontaneously.
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substrates
active site
enzyme
product
How Enzymes Work
Figure 4.7 How an active site works.
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How Enzymes are Regulated
Cofactors or Coenzymes
Figure 4.8 Regulatory molecule binding to enzymes. Some types of regulatory
molecules (red) bind to an enzyme in a place other than the active site. This binding
changes the shape of the enzyme in a way that enhances or inhibits its function.
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Optimum Conditions
Figure 4.9 Enzymes, temperature, and pH.
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ribose
sugar
base (adenine)
phosphate
groups
ATP – Coenzyme
Figure 2.22 Nucleic acids.
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Phosphorylation
Coupled Reaction =
ATP ADP + Pi ATP (Phosphorylation)
NAD+ + electrons + H+ NADH NAD+ + electrons + H+
reactant
product
enzyme 1
enzyme 3
intermediate
intermediate
enzyme 2
Metabolic Pathways
Control:
Feedback inhibition
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Molecular Movement
Passive Transport
Diffusion
Facilitated Diffusion
Osmosis
Solute+Solvent=Solution:
Isotonic
Hypertonic
Hypotonic
D) Osmotic pressure
keeps plant parts erect.
These cells in an iris petal
are plump with cytoplasm.
Figure 4.14 Animated! Effects of tonicity in human red blood cells (A–C) and iris petal cells (D,E).
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E) Cells from a wilted iris petal.
The cytoplasm shrank, and
the plasma membrane has
pulled away from the cell wall.
Figure 4.14 Animated! Effects of tonicity in human red blood cells (A–C) and iris petal cells (D,E).
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Molecular Movement
Passive Transport
Diffusion
Facilitated Diffusion
Osmosis
Extracellular Fluid
ADP
Cytoplasm
Active Transport
Sodium-Potassium Pump
Exocytosis
Endocytosis
Phagocytosis
