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Directions: Read the following two pages. Within each part, identify 1 new piece of information by circling the appropriate sentence it appears and identify 1 piece of information that you already knew by underlying the appropriate sentence. PHOTOSYNTHESIS PART I: THE SUN AND LIGHT Not all of the light from the Sun makes it to the surface of the Earth. Even the light that does make it here is reflected and spread out. The little light that does make it here is enough for the plants of the world to survive and go through the process of photosynthesis. Light is actually energy, and when that energy gets to a green plant, all sorts of reactions can take place to store energy in the form of sugar molecules. Remember how we said that not all the energy from the Sun makes it to plants? Even when light gets to a plant, the plant doesn't use all of it. It actually uses only certain colors to make photosynthesis happen. Plants mostly absorb red and blue wavelengths. When you see a color, it is actually a color that the object does NOT absorb. In the case of green plants, they do not absorb light from the green range. PART II: THE CHLOROPLAST Photosynthesis happens in the chloroplast. Within this cell organelle is the chlorophyll that captures the light from the Sun. We'll talk about it in a bit, but the chloroplasts are working night and day with different jobs. PART III: THE MOLECULES Chlorophyll is the magic compound that can grab that sunlight and start the whole process. Chlorophyll is actually quite a varied compound. There are four (4) types: a, b, c, and d. Chlorophyll can also be found in many microorganisms and even some prokaryotic cells. However, as far as plants are concerned, the chlorophyll is found in the chloroplasts. The other big molecules are water (H2O), carbon dioxide (CO2), oxygen (O2) and glucose (C6H12O6). Carbon dioxide and water combine with light to create oxygen and glucose. The glucose formed during photosynthesis is used in various forms by every creature on the planet. PART IV: LIGHT AND DARK REACTIONS The whole photosynthesis process doesn't happen all at one time. It is divided into two main parts. The first part is called the light dependent reaction. This reaction happens when the light energy is captured (during the day) and pushed into a chemical called ATP. The second part of the process happens when the ATP is used to make glucose (the Calvin Cycle). That second part is called the light independent reaction (doesn’t need light). CELLULAR RESPIRATION PART V: MITOCHONDRIA – TURNING ON THE POWERHOUSE Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system that takes in nutrients, breaks them down, and creates energy for the cell. The process of creating cell energy is known as cellular respiration. Most of the chemical reactions involved in cellular respiration happen in the mitochondria. A mitochondrion is shaped perfectly to maximize its efforts. Mitochondria are very small organelles. You might find cells with several thousand mitochondria. The number depends on what the cell needs to do. If the purpose of the cell is to transmit nerve impulses, there will be fewer mitochondria than in a muscle cell that needs lots of energy. If the cell feels it is not getting enough energy to survive, more mitochondria can be created. Sometimes they can even grow, move, and combine with other mitochondria, depending on the cell's needs. PART VI: MITOCHONDRIA STRUCTURE Mitochondria have two membranes (not one as in other organelles). The outer membrane covers the organelle and contains it kind of like the cell membrane. The inner membrane folds over many times. Many of the chemical reactions happen on the inner part of the mitochondria. The increased number of folds allows the small organelle to do as much work as possible. If you have more room to work, you can get more work done. PART VII: USING OXYGEN TO RELEASE ENERGY How are mitochondria used in cellular respiration? The fluid inside of the mitochondria (called matrix) is filled with water (H2O) and proteins. These proteins take food molecules in the form of glucose and combine them with oxygen (O2). This is the same oxygen we breathe in when we inhale and is why we need to breathe. The mitochondria are the only place in the cell where oxygen can be combined with the food molecules. After the oxygen is added, the material can be digested. Mitochondria are working organelles that keep the cell full of energy. PART VIII: RELEASING ENERGY For cellular respiration to take place, the mitochondria combine the oxygen and glucose to create the products water (H2O), carbon dioxide (CO2), and adenosine triphosphate (ATP). ATP is considered by biologists to be the energy currency of life. This high‐energy molecule stores the energy we need to do just about everything we do. It is stored in the cytoplasm of every cell, and essentially all the parts of the cell that require energy for operation obtain it directly from the stored ATP.