Chapter 5: Photosynthesis and Cellular Respiration

Energy and Living Things Energy in Living Systems ATP

Energy and Living Things Energy in Living Systems – Building molecules that store energy – Breaking down food for energy – Transfer of energy to ATP

Energy in Living Systems Almost all energy in living systems is derived from the sun.

Energy in Living Systems

Building Molecules that Store Energy Metabolism Using energy to build molecules or breaking down molecules in which energy is stored. All organisms metabolize substances!

Building Molecules that Store Energy Photosynthesis – The process by which light is converted to chemical energy.

Building Molecules that Store Energy Autotrophs – Organisms that use energy from sunlight or other inorganic compounds to make organic compounds. – What does organic mean?

Autotrophs Some make energy from sunlight. Some make energy from the chemical reactions of inorganic molecules.

Autotrophs

Breaking Down Food for Energy Heterotrophs – Organisms that must get energy from food instead of directly from sunlight or inorganic substances.

Breaking Down Food for Energy Heterotrophs get energy from food through a process known as cellular respiration. Cellular Respiration – Metabolic process in which the energy of food is released to make ATP. – ATP provides the energy for the activities you perform daily!

Autotroph vs. Heterotroph What is the difference between an autotroph and a heterotroph? Give an example of each.

Transfer of Energy to ATP When cells break down food molecules, some of the energy is released as heat. The rest of the energy is temporarily stored in molecules of ATP.

ATP ATP is a portable form of energy “currency” inside the cell. The energy released from ATP can drive most of the cell’s activities.

Starch Breakdown

ATP Adenosine triphosphate Nucleotide with two extra energy storing phosphates. Phosphate bonds store energy like a compressed spring.

ATP

Draw ATP being converted to ADP with energy being release.

Photosynthesis Photo- light Synthesis- combination

Photosynthesis Using the energy in sunlight Stage 1: Absorption of light energy Stage 2: Conversion of light energy Stage 3: Storage of energy

Photosynthesis The Stages of Photosynthesis Photosynthesis can be summarized as:by the following equation: 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Carbon dioxide water sugars oxygen gas

Photosynthesis What organelle does photosynthesis occur in? What types of cells does photosynthesis occur in?

Photosynthesis Reactions occur inside of chloroplasts

Stage One: Absorption of Light Energy Pigments Production of Oxygen

Pigments Light-absorbing substances

Pigments Chlorophyll- absorbs most of the light for photosynthesis. – What makes plants leaves look green!

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Parts of a Chloroplast Section 2 Photosynthesis Chapter 5

Pigments Carotenoids-absorb the rest of the light energy for photosynthesis. – What is responsible for the red and yellow colors of leaves right now!!

Pigments What is the function of pigments in photosynthesis? What is the main pigment in photosynthesis? What pigment causes leave to look red yellow and orange during the fall?

Pigments Absorb light energy for photosynthesis.

Production of Oxygen Clusters of pigments are located inside of disk- shaped structures called thylakoids.

Production of Oxygen

Light strikes thylakoid in the chloroplast. Electrons become excited and energy is transferred in chlorophyl.

Production of Oxygen Excited electrons power second stage of photosynthesis. These electrons must be replaced when they leave the chlorophyll.

Production of Oxygen Electrons are replaced by the splitting of water by enzymes. Water is split inside the thylakoid. Chlorophyll molecules take electrons from split water. Positive Hydrogen ion and oxygen gas are left over. THIS IS THE STEP WHERE OXYGEN GAS IS MADE!!

Photosynthesis Stage 1 Write a summary of phase 1 of photosynthesis.

Photosynthesis Stage 1 Summary Conversion of light to energy Pigments absorb light Light energy excites electrons in thylakoid. Electrons are replaced by the splitting of water Hydrogen ions and oxygen gas are the result. The excited electrons carry over into step 2.

Stage 2: Conversion of Light to Energy Excited electrons are passed along an electron transport chain.

Electron Transport Chains Electron transport chain between two green pigments. Protein that acts as a large pump. Electrons pass their energy on to this pump. Pump uses energy to pump hydrogen ions into the thylakoid. Hydrogen ions used to turn ADP into ATP!

Second Electron Transport Chain NADPH – Electron carrier that provides the high-energy electrons needed to make carbon-hydrogen bonds in the third stage of photosynthesis.

Excited electrons combine with hydrogen ions and an electron acceptor )NADP+, forming NADPH.

Stage 2 Summary High energy electron used to pump Hydrogen ion across membrane. Hydrogen ion used to make ATP High energy electron combines with NADP+, an electron acceptor that provides energy needed for carbon-hydrogen bonds to form.

Stage 3: Storage of Energy Calvin Cycle Factors that Affect Photosynthesis

Converting Light Energy to Chemical Energy

Stage 3 ATP and NADPH were made using energy from the sun. Carbon atoms from Carbon dioxide will be used to create compounds in the Calvin Cycle. This transfer of Carbon Atoms is known as carbon dioxide fixation.

Calvin Cycle Series of enzyme-assisted chemical reactions that produces a three-carbon sugar. Translate please? What does that mean???

Calvin Cycle 1.) Carbon dioxide is added to a compound by an enzyme. 2.) 6 Carbon compound is split into 2 three carbon sugars. 3.) One of the three carbon sugars is used to make starch and sucrose that store energy for the organism. 4.) The other three carbon sugars regenerate the initial 5 carbon compound.