A-Level Biology Energy Transfers In And Between Organisms

III. Respiration
A. Respiration
1. Definition: the process by which organisms convert glucose into ATP (adenosine
triphosphate) to release energy.
2. Cellular respiration can be divided into three stages: glycolysis, the Krebs cycle, and the
electron transport chain.
B. Glycolysis
1. Occurs in the cytoplasm of cells.
2. Glucose is broken down into pyruvate, producing a net of two ATP molecules.
3. Glycolysis is anaerobic, meaning it does not require oxygen.
C. The Krebs Cycle
1. Occurs in the mitochondria of cells.
2. Pyruvate is converted into acetyl CoA, which enters the Krebs cycle.
3. The Krebs cycle produces ATP, NADH, and FADH2.
4. The Krebs cycle requires oxygen to function.
D. The Electron Transport Chain
1. Occurs in the inner mitochondrial membrane.
2. NADH and FADH2 produced during the Krebs cycle donate electrons to the electron
transport chain.
3. Electrons are transported along a series of protein complexes, which releases energy that is
used to pump protons across the inner mitochondrial membrane.
4. The energy stored in the proton gradient is used to drive the synthesis of ATP.
E. Aerobic and Anaerobic Respiration
1. Aerobic respiration requires oxygen and produces much more ATP than anaerobic
respiration.
2. Anaerobic respiration occurs in the absence of oxygen and produces less ATP.
3. Lactic acid fermentation and alcoholic fermentation are two types of anaerobic respiration.
F. Chloroplast Structure and Function
1. Chloroplasts are organelles found in plant cells.
2. Chloroplasts are responsible for photosynthesis, the process by which plants convert
sunlight into energy.
3. Chloroplasts have a double membrane, an inner and outer membrane.
4. Within the chloroplasts are thylakoids, stacks of membranes where light-dependent reactions
take place.
5. Chlorophyll, the pigment that gives plants their green color, is located in the thylakoid
membranes and is responsible for absorbing sunlight.
6. The light-independent reactions of photosynthesis occur in the stroma of the chloroplasts,
where CO2 is fixed into glucose.

, I. Introduction
 Importance of energy transfer in organisms
 Overview of photosynthesis and respiration
 Explanation of energy flow in ecosystems
II. Photosynthesis
 Definition and overview
 Chloroplast structure and function
 Light-dependent reactions
 Light-independent reactions (Calvin cycle)
 Factors affecting photosynthesis
III. Respiration
 Definition and overview
 Aerobic respiration
 Anaerobic respiration
 The role of mitochondria in respiration
 Factors affecting respiration
IV. Energy and Ecosystems
 Food chains and food webs
 Trophic levels
 Energy transfer efficiency
 Pyramid of biomass, energy and numbers
V. Nutrient Cycles
 The carbon cycle
 The nitrogen cycle
 The water cycle
 The role of microorganisms in nutrient cycles
VI. Importance of Energy Transfers in Biology
 Role of energy in maintaining homeostasis
 Impact of energy use on the environment
 Applications of energy transfer knowledge in agriculture and industry
VII. Data Analysis in Energy Transfer Studies
 Use of graphs and tables
 Calculations of energy transfer efficiency
 Interpretation of data
VIII. Scientific Communication in Energy Transfer Studies
 Writing scientific reports
 The importance of accurate and clear communication