Topic 5.1: Matter and Energy Pathways in Living Systems Chapter 5 Topic 5.1: Matter and Energy Pathways in Living Systems
ENERGY STORAGE and TRANSFORMATION There are two important types of energy storage Photosynthesis solar energy is converted to chemical bond energy within carbohydrates Cellular Respiration carbohydrates are converted into ATP ATP is needed for chemical reactions in cells, active transport, and muscle contractions
Complementary Processes
ENERGY STORAGE and TRANSFORMATION Capturing Light Energy The Electromagnetic Radiation spectrum (EMR) contains visible light 400 – 700 nm in wavelength
ENERGY STORAGE and TRANSFORMATION Photosynthetic pigments are compounds that trap light energy Carotenoids absorb blue and green light They are red, yellow and orange (carotene) Absorbance Spectrum of Three Pigments
ENERGY STORAGE and TRANSFORMATION Chlorophyll (a & b) is a pigment that makes plants green Absorbs violet, blue and red light It is found in the chloroplasts Clusters of pigment molecules are called photosystems
CHLOROPLASTS The Structure of a Chloroplast Outer membrane Inner membrane Intermembrane space Thylakoids (Gr. “sack”, “form of”) – disks inside the chloroplast Granum (grana, pl.) – stack of thylakoid disks Thylakoid lumen – space inside the thylakoid disk Thylakoid membrane – specialized cell membranes containing photosynthetic pigments; photosynthesis takes place here Stroma - gel-like substance surrounding the grana that is rich in enzymes and other chemicals Draw in your notes and label
Metabolism and Enzymes The chemical reactions of photosynthesis and cellular respiration take place in a series of step-by-step reactions called metabolic pathways. Catabolism: Anabolism: Enzymes are biological catalysts that reduce the amount of startup energy needed for the reactions in the metabolic pathways. In the absence of enzymes, the reactions could not occur at temperatures at which living organisms thrive.
Oxidation and Reduction When a compound is oxidized in a chemical reaction, it loses electrons. When a compound is reduced in a chemical reaction, it gains electrons. Compounds contain more chemical energy in their reduced form than they do in their oxidized form.
Mitochondria The inner membrane has many deep infoldings called cristae. Mitochondria have outer and inner membranes that surround a fluid-filled region called the matrix.
Review Questions What is ATP? Describe what happens when an enzyme steals a phosphate from ATP. What has more energy, the reactants or the products? Name the two types of energy storage. Describe the energy transformations that occur in each. List the structures found in a chloroplast. Where in the chloroplast are photosynthetic pigments found? An enzyme has an optimal temperature of 36C. Describe what would happen if it was stored at 15C? At 40C?