Overview of Photosynthesis Most autotrophs (organisms that create their own food), make organic compounds (sugars/glucose) using a process called photosynthesis. This process occurs only in plants.
Overview of Photosynthesis Photosynthesis is the process in which light energy is converted into chemical energy and can be shown by the following equation:
Overview of Photosynthesis Photosynthesis occurs in two stages: Light-dependent reactions (requires light) Light-independent reactions (does not require light)
Phase One: Light Reactions (Light- Dependent) Plants must first capture light. They have special organelles called chloroplasts located in the leaves of a plant that help them to capture light energy.
Phase One: Light Reactions (Light-Dependent) Chloroplasts contain specialized structures to help them carry out the two part process of photosynthesis. Thylakoid: flattened, sac-like membranes that are arranged in stacks Grana (granum): stacks of thylakoids Stroma: the fluid-filled space that is outside the grana
Phase One: Light Reactions (Light- Dependent) The thylakoid membranes of a plant s chloroplasts hold pigments, which are special light absorbing molecules. Plants appear green because of chlorophyll pigments found in the chloroplasts.
Phase One: Light Reactions (Light- Dependent) When there s a change in temperature in certain parts of the US, chlorophyll pigments begin to break down. Other pigments called carotenoids may bring out shades of yellow, red, and orange.
Phase One: Light Reactions (Light- Dependent) Light reactions take place in the thylakoids of a plant cell and consist of the electron transport chain (or ETC). At the end of the light reactions, we have formed the energy-storage molecules NADPH and ATP.
Phase One: Light Reactions (Light-Dependent)
Phase 2: The Calvin Cycle (Light- Independent) Plants must convert NADPH and ATP into organic molecules called glucose (sugar), that can be used by the plant. At the end of the Calvin Cycle, the plant has formed sugars, which can be used for energy and as building blocks for complex carbs, which make up cellulose and provide support for the plant.
The Calvin Cycle
Overview of Cellular Respiration The function of cellular respiration is to take glucose and use the energy stored there to make ATP, which can then be used by the cells to carry out essential processes. This process occurs in BOTH plants and animals.
Overview of Cellular Respiration Cellular respiration occurs in the mitochondria of the plant or animal cell, and can be shown by the following equation:
Overview of Cellular Respiration Cellular respiration occurs in two main parts: glycolysis and aerobic respiration Stage one, glycolysis, is considered anaerobic because it does not require oxygen. Stage two, which includes the Krebs Cycle and ETC, is considered aerobic because it does require oxygen.
Phase One: Glycolysis (Anaerobic) Glycolysis occurs in the cytoplasm of the cell and is the process of breaking down the glucose. At the end of glycolysis, we have formed ATP and pyruvate molecules.
Phase Two: Aerobic Respiration (Krebs Cycle & ETC) The Krebs Cycle is often referred to as the Citric Acid Cycle. In the Krebs Cycle, the pyruvate molecules are broken down because they still hold most of the energy. At the end of the Krebs Cycle, we are left with carbon dioxide molecules, ATP, NADH, and FADH 2
Phase Two: Aerobic Respiration (Krebs Cycle & ETC) The NADH and FADH 2 go on to be used by the ETC to convert ADP to ATP. The ETC produces most of the energy, or ATP.
Phase Two: Aerobic Respiration (Krebs Cycle & ETC) In eukaryotic organisms (those made up of more than one cell), the ETC produces 36 ATP that the organism can use for essential processes. In prokaryotic organisms (those made up of only one cell), the ETC produces 38 ATP that the organism can use for essential processes.
Anaerobic Respiration In the event oxygen is not present for the cell to undergo the Krebs Cycle and ETC, it will than do an alternate process called fermentation. Fermentation produces less ATP molecules than aerobic respiration, so it is not as efficient.
Anaerobic Respiration There are two types of fermentation: lacticacid fermentation which produces lactic acid, and alcohol fermentation which produces alcohol. Organisms such as yeast and bacteria undergo fermentation to produce beer, wine, cheese, and yogurt.