Photosynthesis and Cellular Respiration

Standard Cell Biology 1F Students know useable energy is captures 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 is the unit of energy for all cells ATP: Energy for Cells ATP is the unit of energy for all cells ATP= Adenosine Triphosphate 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.

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 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: Light Dependent Reactions Takes in water Gives off energy molecules called ATP Gives off Oxygen 2. Calvin Cycle Takes 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 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 ATP Two 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 Anaerobic Requires oxygen Glycolysis, Krebs cycle and electron transport 28 ATP total No oxygen Glycolysis followed by fermentation 4 ATP total

Fermentation (anaerobic) Lactic Acid Alcohol Fermentation Can build up in skeletal muscle = soreness In microorganisms, used to make yogurt, cheese and sour cream 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 reactions Proteins 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 reactions The same enzyme can be used over and over to combine the same molecules An enzyme is like a tool: you can use the same hammer over and over again to nail together boards.