Energy in a Cell Chloroplast Mitochondria (plant cells only) (both plant and animal cells)

Cell Energy I. Cell Energy A. Energy (the ability to do work) is essential in order for organisms and their cells to function. B. cells get this energy from the food you eat

Cell Energy C. After you have eaten, food is broken down into nutrient molecules that can enter your cells (this is before it has reached your bloodstream).

Cell Energy D. Cells then breakdown the food molecules while releasing energy needed for the biological work your cells need to perform.

Cell Energy E. BUT cells cannot use all the energy available in food molecules at once. F. Food molecules are broken down in different steps. At each of these steps, energy is released and stored in the form of ATP.

Cell Energy G. Then, the energy can be released from ATP for later use in cell work.

ATP II. ATP A. ATP is the cell’s energy currency.   B. Cells break down food molecules and distributes the energy to ATP molecules. C. ATP = adenosine triphosphate

ATP D. Without a constant supply of ATP, cells will die.   E. Energy is stored when ATP is made from ADP and phosphate.

ATP F. Energy is released when ATP breaks down to ADP and phosphate. G. ATP is then broken down into ADP and phosphate.

Adenosine Triphosphate 2.Releasing Energy: energy that is released by breaking apart phosphate groups in ATP can be used to power cell activities. 1. Stored Energy: Energy is stored in chemical bonds. The phosphate bonds in ATP are especially useful for storing energy ATP Energy for cells Energy from food 4. Making ATP: energy released by other chemical reactions can be used to bond a phosphate group to ADP, making ATP. 3. Energy Depleted: ADP has less chemical energy than ATP ADP + P

Repsiration III. Respiration A. The process by which food molecules are broken down to release energy is called respiration.

glucose + O2 ---> CO2 +H2O + energy Respiration B. Reactions of Respiration: The chemical equation of respiration is: glucose + O2 ---> CO2 +H2O + energy products reactants

Respiration IV. Releasing energy ( Respiration) A. This begins with the process of glycolysis. 1. 2 molecules of ATP are yielded per molecule of glucose broken down. B. Glycolysis the anaerobic process of splitting glucose.

Aerobic Respiration C. When oxygen is present, aerobic respiration takes place in the mitochondria D. Aerobic respiration involves two or more steps after glycolysis: breakdown of pyruvic acid and the citric acid cycle.

Anaerobic Respiration E. If oxygen is not present after glycolysis, anaerobic respiration takes place. F. This process is fermentation. G. No additional ATP is formed during the process of fermentation.

Anaerobic Respiration H. If lactic acid is formed at the end of fermentation, the process is called lactic acid fermentation  I. If alcohol and carbon dioxide is formed at the end of fermentation, the process is called alcoholic fermentation

Anaerobic Respiration Carbon dioxide Methanol Alcohol Fermentation Pyruvic acid Lactic Acid Fermentation Lactic Acid

Photosynthesis V. Photosynthesis A.  Plants must break down food to made ATP. However, they don’t ingest their food, they make it.

Photosynthesis B. Autotrophs and Sunlight 1. Autotrophs trap energy from the sun and use it to build carbohydrates.   2. Chlorophyll, the pigment that makes plants green, reflect green and some yellow light while trapping the energy of the others colors.

Photosynthesis 3. This energy is used for photosynthesis.   4. Chlorophyll is found in the chloroplasts of green plants and algae. 5. Chloroplasts are surrounded by two lipid bilayer membranes.

Photosynthesis 6. The insides of chloroplasts consists of a series of thylakiod membranes.   7. Sunlight is trapped by chlorophyll within the thylakiod membranes.

Photosynthesis C. Photosynthesis and Respiration are a cycle 1. photosynthesis: CO2 +H2O + energy--->glucose + O2 2. Respiration: glucose + O2 ---> CO2 +H2O + energy

Photosynthesis

Photosynthesis VII. Photosynthesis includes two main groups of reactions: 1. light reactions 2. Calvin cycle

Photosynthesis A. During the light reactions, light energy is converted to chemical energy. B.The light reactions split water molecules, providing hydrogen and an energy source for the Calvin cycle.

Photosynthesis C. The Calvin cycle is the series of reactions that forms simple sugars using carbon dioxide and hydrogen from water. Glucose

Reflection Questions 1. Where do cells get their energy from? 2. What is the purpose of ATP? 3. What are autotrophs? 4. What is the purpose of photosynthesis? 5. What is the purpose of respiration?