1. Topic 5.1: Matter and Energy Pathways in Living Systems
Chapter 5
Topic 5.1: Matter and Energy Pathways in Living Systems

2. 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

3. Complementary Processes

4. ENERGY STORAGE and TRANSFORMATION
Capturing Light Energy
The Electromagnetic Radiation spectrum (EMR) contains visible light 400 – 700 nm in wavelength

5. 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

6. 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

7. 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

10. 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.

11. 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.

12. 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.

13. 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 36C. Describe what would happen if it was stored at 15C? At 40C?