Photosynthesis and Cellular Respiration. Standard Cell Biology 1F Students know useable energy is...
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Transcript of Photosynthesis and Cellular Respiration. Standard Cell Biology 1F Students know useable energy is...
Photosynthesis and Cellular Respiration
Standard Cell Biology 1F
Students know useable energy is captured from sunlight by chloroplasts and is stored through the synthesis of sugar.
At the end of this lesson…
Students will know all energy on Earth comes from the sun
Students will be able to create a flow map illustrating photosynthesis
What is Energy?
Energy is the ability to do work or grow
All Energy on the earth comes from the sun
Plants and animals get their energy in different ways.
ATP: Energy for Cells
ATP is the unit of energy for all cellsATP= Adenosine
TriphosphateATP 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.
Photosynthesis
Photosynthesis is the process plants use to make energy for themselves
Photosynthesis uses the energy from the sun to make glucose and take carbon from the air (CO2 ) to use for growth
Photosynthesis
• Photosynthesis takes place in the chloroplasts of plant cells. • Chloroplasts contain the pigment Chlorophyll, which absorbs
certain wavelengths of light. • What is the closest equivalent of a chloroplast in an animal
cell?
Photosynthesis
The Photosynthesis Reaction
Carbon Dioxide and water combine in the presence of sunlight to make glucose (a sugar) and oxygen gas.
Why is light necessary? Why are plants necessary for photosynthesis to occur?
Photosynthesis Occurs in 2 steps:
1. Light Dependent Reactions Takes in water Gives off energy
molecules called ATP
Gives off Oxygen
2. Calvin CycleTakes in Carbon
Dioxide– Gives off glucose
Light Dependent Reactions:
• Chloroplasts capture light energy
• Takes place in the Thylakoid (Stack of membranes in chloroplast)
• Require water and sunlight• Water is split, releasing
hydrogen ions• Hydrogen ion is used to
attach a phosphate group to ADP, making it ATP
• Visualizing Light Dependent Reactions
Step 2: The Calvin Cycle
The Calvin Cycle uses carbon dioxide and creates carbohydrates, or glucose.
6 molecules of carbon dioxide are used to create 1 glucose molecule
6 ATP molecules are required to create 1 glucose molecule
Where does the glucose go?
• Glucose is used in plant cells to make starches
• Starches are stored in vacuoles until they are needed later by the plant
• Plants use transport systems like blood vessels to move starches throughout the plant
• To grow, plants combine Carbon that they get from Carbon dioxide and glucose to build new tissues
• Plants are consumed by heterotrophs, who use the starches for their own energy.
How do animals (and plants) get energy?
Animals convert the glucose stored in plants into ATP for their own use
This process is called Cellular respiration
The equation for this process is the OPPOSITE reaction from photosynthesis:
Cellular Respiration takes place in the mitochondria
Occurs in 3 steps:
Cellular Respiration: Oxygen is the Key!
Cellular Respiration
Cellular respiration occurs in three steps:Step 1: glycolysis
Glycolysis means “To break down sugar”Cell breaks down glucose from the food we
eat Turns glucose into pyruvate, which can be
used to make ATPTwo molecules of ATP are made in the
process of glycolysis
Step 2: Krebs Cycle
Most of the energy from the glucose is still contained in the pyruvate.
The Krebs Cycle takes the pyruvate made in glycolysis and creates 2 ATP molecules
Step 3: Electron Transport Chain!
The electron transport chain produces the most ATP in the process of Cellular Respiration
Concentration gradients inside and outside of the mitochondrion create 32 ATP molecules
What are the numbers?
Photosynthesis Cellular Respiration
• Creates a total of 24 ATP molecules
• Creates a total of 36 ATP molecules
Food and ATP
Cellular Respiration
AerobicRequires oxygenGlycolysis, Krebs
cycle and electron transport
28 ATP total
Anaerobic No oxygen Glycolysis
followed by fermentation
4 ATP total
Fermentation (anaerobic)
Lactic Acid Can build up in
skeletal muscle = soreness
In microorganisms, used to make yogurt, cheese and sour cream
Alcohol Fermentation Sugar cane -> rum Wheat -> beer Potatoes -> vodka Grapes -> wine Agave -> tequila Rice -> sake
How does all of the breaking down and building of molecules occur?
ENZYMES!
Enzymes
Enzymes are proteins that help to speed up chemical reactionsProteins are made of chains of amino
acids, which are present in all of our (naturally created) food
There are thousands of enzymes present in every cell of your body
Each enzyme has a specific function Enzyme names usually end in –ase
(such as hydrolase)
Properties of Enzymes
Enzymes are not used up in reactionsThe same enzyme can be used over
and over to combine the same moleculesAn enzyme is like a tool: you can use the
same hammer over and over again to nail together boards.