Transformation of Energy Energy is the ability to do work ...
Transcript of Transformation of Energy Energy is the ability to do work ...
Transformation of Energy
! Energy is the ability to do work.
How Organisms Obtain Energy Cellular Energy
! Thermodynamics is the study of the flow and transformation of energy in the universe.
Section 1
Laws of Thermodynamics
! First law—energy can be converted from one form to another, but it cannot be created nor destroyed.
How Organisms Obtain Energy Cellular Energy
! Second law—energy cannot be converted without the loss of usable energy.
Section 1
Autotrophs and Heterotrophs
! Autotrophs are organisms that make their own food.
How Organisms Obtain Energy Cellular Energy
! Heterotrophs are organisms that need to ingest food to obtain energy.
Section 1
Metabolism
! All of the chemical reactions in a cell
How Organisms Obtain Energy Cellular Energy
! Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell
! Cellular respiration—organic molecules are broken down to release energy for use by the cell
Section 1
ATP: The Unit of Cellular Energy
! ATP releases energy when the bond between the second and third phosphate groups is broken, forming a molecule called adenosine diphosphate (ADP) and a free phosphate group.
How Organisms Obtain Energy Cellular Energy Section 1
ATP
Overview of Photosynthesis
! Photosynthesis occurs in two phases.
Cellular Energy
! Light-dependent reactions
! Light-independent reactions
Photosynthesis Section 2
Phase One: Light Reactions
! The absorption of light is the first step in photosynthesis.
Cellular Energy
! Chloroplasts capture light energy.
Photosynthesis Section 2
Electron Transport
! Light energy excites electrons in photosystem II and also causes a water molecule to split, releasing an electron into the electron transport system, H+ into the thylakoid space, and O2 as a waste product.
Cellular Energy
Photosynthesis Section 2
! The excited electrons move from photosystem II to an electron-acceptor molecule in the thylakoid membrane.
! The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem I.
Cellular Energy
Photosynthesis Section 2
Cellular Energy
Photosynthesis
! Photosystem I transfers the electrons to a protein called ferrodoxin.
! Ferrodoxin transfers the electrons to the electron carrier NADP+, forming the energy-storing molecule NADPH.
Section 2
Cellular Energy Section 2
Cellular Energy
Photosynthesis
Phase Two: The Calvin Cycle
! In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.
Section 2
Cellular Energy Section 2
Cellular Energy
Photosynthesis
! Six CO2 molecules combine with six 5-carbon compounds to form twelve 3-carbon molecules called 3-PGA.
! The chemical energy stored in ATP and NADPH is transferred to the 3-PGA molecules to form high-energy molecules called G3P.
Section 2
Cellular Energy
Photosynthesis
! Two G3P molecules leave the cycle to be used for the production of glucose and other organic compounds.
! An enzyme called rubisco converts the remaining ten G3P molecules into 5-carbon molecules called RuBP.
! These molecules combine with new carbon dioxide molecules to continue the cycle.
Section 2
Cellular Energy
Photosynthesis
Alternative Pathways
! C4 plants
! CAM plants
Section 2
Overview of Cellular Respiration
! Organisms obtain energy in a process called cellular respiration.
Cellular Respiration Cellular Energy
! The equation for cellular respiration is the opposite of the equation for photosynthesis.
Section 3
Cellular Respiration Cellular Energy
! Cellular respiration occurs in two main parts.
! Glycolysis
! Aerobic respiration
Section 3
Glycolysis
! Glucose is broken down in the cytoplasm through the process of glycolysis.
Cellular Respiration Cellular Energy
! Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.
Section 3
Krebs Cycle
! Glycolysis has a net result of two ATP and two pyruvate.
Cellular Respiration Cellular Energy
! Most of the energy from the glucose is still contained in the pyruvate.
! The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.
Section 3
Cellular Respiration Cellular Energy
! The net yield from the Krebs cycle is six CO2 molecules, two ATP, eight NADH, and two FADH2.
Section 3
Cellular Energy Section 3
Cellular Respiration Cellular Energy
Electron Transport
! Final step in the breakdown of glucose
! Point at which ATP is produced
! Produces 24 ATP
Section 3
Cellular Respiration Cellular Energy
Anaerobic Respiration
! The anaerobic pathway that follows glycolysis
! Two main types
! Lactic acid fermentation
! Alcohol fermentation
Cellular Respiration
Section 3