Unit 2: Cells Objective 1: Describe the fundamental chemistry of living cells Objective 2: Describe the flow of energy and matter in cellular function Objective 3: investigate the structure and function of cells and cell parts

How do Organisms Obtain Energy? Energy is a property of matter that is defined as the ability to do work. All organisms need energy to grow and reproduce. Energy can never be created nor destroyed, it is always conserved (law of conservation of energy). Organisms obtain energy and then change it from one form to another. Plants change light energy to chemical energy; other organisms eat and digest the food, break the chemical bonds and release the chemical energy. About 90% of the energy obtained from food is converted to heat energy and given off to the environment.

Overview of ATP Adenosine triphosphate (ATP) is the primary energy source for cells. ATP stores chemical energy in its bonds. This energy is used for cell metabolism and to maintain cell homeostasis.

Autotrophic vs Heterotrophic Activity You will compare the characteristics of autotrophic and heterotrophic cells to create a Venn diagram, identify pictures and write a creative paragraph. file:///C:/Users/heather.lee/Downloads/Pictures.pdf

Autotroph Vs Heterotroph Autotrophs store chemical energy in carbohydrate food molecules they build themselves. Most autotrophs transform sunlight to make food in a process known as photosynthesis. Only three groups of organisms are capable of this life-giving energy transformation: Plants Algae Some bacteria Autotrophs are known as producers, as they make their own food and begin all food chains.

Autotroph vs Heterotroph Heterotrophs cannot make their own food, so they must eat or absorb it. Thus, they are known as consumers. Consumers include: All animals Fungi Many protists & bacteria They may consume autotrophs or other heterotrophs or organic molecules from other organisms.

History and the Equation for Photosynthesis Activity You will use descriptions of several of the famous experiments to lead you to the equation for photosynthesis. http://www.bozemanscience.com/photosynthesis

Photosynthesis: How do plants make Food? Photosynthesis is the process by which plants use the sun’s energy to make their own “food” from carbon dioxide and water.

Where does the energy come from? Photosynthesis converts the energy of the sun, or solar energy, into carbohydrates, a type of chemical energy. During photosynthesis, carbon dioxide and water combine with solar energy, yielding glucose (the carbohydrate) and oxygen.

Photosynthesis Photosynthesis mostly takes place in the leaves of a plant, the green pigment (chlorophyll) helps to capture solar energy. The veins of the leaf carry water which originates from the roots and carbon dioxide enters through pores called stomata. Chloroplasts are the organelles in which photosynthesis takes place.

The equation of Photosynthesis The overall chemical reaction for photosynthesis is 6 molecules of carbon dioxide (CO2) and 6 molecules of water (H2O), with the addition of solar energy, yields 1 molecule of glucose (C6H12O6) and 6 molecules of oxygen.

Oxygen: An essential byproduct Plants and other photosynthetic organisms play an important ecological role in converting carbon dioxide into oxygen. Animals need oxygen to carry out the energy- producing reactions of their cells. Without photosynthetic organisms, many other organisms would not have enough oxygen in the atmosphere to survive.

Light Reactions The overall process of photosynthesis does not happen in one step. The first step are known as light-dependent reactions because they only occur during daylight hours. During the light reactions, sunlight splits water to release oxygen and capture its energy. Steps of Light Reactions Light hits chlorophyll Electrons are excited Water is split into oxygen and hydrogen ions Hydrogen ion gradient produced Hydrogens move through ATP synthase producing ATP Hydrogens from ATP synthase combines with NADP to form NADPH

The second step is known as the Calvin Cycle (Dark Reaction), during this reaction carbon dioxide is converted into glucose. The Calvin Cycle begins with carbon dioxide attaching to the carbon molecule RuBP, forming a 6-carbon molecule and splitting immediately into two 3-carbon molecules. After 2 cycles Glucose is the final product. The 3-carbon product of the Calvin Cycle can be converted into many types of organic molecules. Glucose, the energy source of plants and animals, or cellulose, a structural carbohydrate, or starch, a long term storage carbohydrate.

Putting it Together Photosynthesis is crucial to most ecosystems since animals obtain energy by eating other animals, or plants and seeds that contain these organic molecules. In fact, it is the process of photosynthesis that supplies almost all the energy to an ecosystem. Photosynthesis crash course: http://www.youtube.com/watch?v=sQK3Yr4Sc_k Photosynthesis song: http://www.youtube.com/watch?v=C1_uez5WX1o