CELLULAR ENERGY
PHOTOSYNTHESIS
The Process that Uses the Sun’s energy to make simple sugars
Two Stages Light dependent reactions Light independent reactions (Calvin Cycle)
LIGHT DEPENDENT REACTIONS
Occur in the Chloroplast Where light energy is trapped by the
pigment chlorophyll in the thylakoid membrane
The light energy excites electrons in chlorophyll which are transferred down an electron transport chain where their energy is harvested.
ELECTRON TRANSPORT CHAIN
A series of proteins that are embedded in a membrane (chloroplast in plants, mitochondria in animals) which pass electrons from higher to lower energy states
By doing so generate ATP from ADP Water is split, oxygen is given off and
the hydrogen (H+) are used
LIGHT INDEPENDENT REACTIONS
Also called the Calvin cycle Is a series or reactions that use CO2 to
form six carbon sugars (such as glucose)
These sugars are then used by a plant to grow or for energy storage Why does a plant need to store energy
PHOTOSYNTHESIS REVIEW
Carbon from CO2 is used with energy from the sun to make sugars for the plant to grow and for storage
CELLULAR RESPIRATION
Cellular respiration is the process by which mitochondria break down food molecules to produce ATP
There are 3 stages Glycolysis Citric Acid Cycle (Krebs Cycle) Electron Transport Chain
GLYCOLYSIS
Is a series of chemical reactions in the CYTOPLASM of a cell that break down glucose (6 carbon sugar) into two 3 carbon molecules
Requires 2 ATP to start the process and makes 4 ATPs, therefore the net gain is 2 ATP
Gives off CO2 in the process Sends off electrons to the electron transport
chain
Simplified, Glycolysis
breaks down glucose (a six-carbon molecule) into two 3-carbon molecules (pyruvic acid) and makes net 2 ATP
CITRIC ACID CYCLE (KREBS CYCLE)
Uses the 3 carbon molecules (2) from glycolysis in a cycle of chemical reactions to produce 2 ATP and 4 CO2
Also passes more electrons to the electron transport chain from more ATP synthesis
THE ELECTRON TRANSPORT CHAIN
Found on the membrane of the mitochondria for cellular respiration
Passes high energy electrons along specialized proteins from higher to lower energy states until the electrons are accepted by Oxygen Why is oxygen important?
Overall produces 32 ATP per glucose molecule
OVERALL ENERGY YIELD
Glycolysis 4 – 2 = 2 ATP
Citric Acid Cycle 2 ATP
Electron Transport Chain 32 ATP
AEROBIC RESPIRATION
Is a process that occurs in the presence of oxygen, such as cellular respiration
However, if oxygen isn’t available cells can also make limited ATP via anaerobic respiration Process that occurs without air
FERMENTATION
A way by which a cell can continue to produce ATP when it is in a anaerobic environment
2 types Lactic Acid Alcoholic
LACTIC ACID FERMENTATION
Occurs during strenuous exercise and oxygen is not available
Glycolysis still works and the net 2 ATP are still formed
The remaining 3 Carbon molecular byproducts (which normally would go into the citric acid cycle) are converted into lactic acid
LACTIC ACID FERMENTATION
Lactic acid is then sent in the blood to the liver to be converted back into the useable products of the citric acid cycle once oxygen is present again
Large build up can become toxic to the body
ALCOHOLIC FERMENTATION
Primarily used by yeast and bacteria cells to produce CO2 and ethyl alcohol
Net product is 2 ATP per glucose molecule, 2 from glycolysis and 2 alcohol molecules from fermentation to alcohol
Ethyl alcohol is the storage molecule until oxygen is present again
ATP PRODUCTION REVIEW Aerobic respiration
36 ATP Lactic Acid Fermentation
2 ATP Alcoholic Fermentation
2 ATP
PHOTOSYNTHESIS CELLULAR RESPIRATION
Food Synthesized Energy from sun stored
as glucose CO2 taken in Oxygen given off Requires light Occurs only in the
presence of chlorophyll
Food broken down Energy of glucose
released CO2 given off Oxygen taken in CO2 given off Does not require light Occurs in ALL living
cells
OPEN BOOK QUIZ
What is the difference between an Autotroph and a Heterotroph
Which ones run photosynthesis
Give an example of each type