Unit 2 Energy of Life: Carbohydrates and Cellular Energetics

Text sections: 3.36.1, 6.2, 6.37.1, 7.2, 7.3, 7.4, 7.5, 7.68.1, 8.2, 8.3

Expected Test Date: Thursday, October 13

Brief Outline

I. Carbohydrates: Fuel and Building Material

  1. Sugars, the smallest carbohydrates, serve as fuel and carbon sources
  2. Polysaccharide, the polymers of sugars, have storage and structural roles

II. Metabolism, Energy and Life

A. the chemistry of life is organized into metabolic pathways

B. energy transformations of life are subject to 2 laws of thermodynamics

C. organisms live at the expense of free energy

D. ATP powers cellular work by coupling exergonic to endergonic reactions

III. Principles of Energy Conservation

A. Cellular respiration and fermentation are catabolic pathways

B. Cells must recycle the ATP they use for work

C. Redox reactions release energy when electrons move closer to electronegative atoms

D. Electrons “fall” from organic molecules to oxygen during cellular respiration

E. The “fall” of electrons during respiration is stepwise, via NAD+ and an electron transport chain

IV. The Process of Cellular Respiration

A. Respiration involves glycolysis, the Krebs cycle, and Electron transport

B. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate

C. The Krebs cycle completes the energy-yielding oxidation of organic molecules

D. The inner mitochondrial membranecouples electron transport to ATP synthesis

E. Cellular respiration generates many ATP molecules for each molecule of sugar

V. Related metabolic Processes

A Fermentation enables some cells to produce ATP without the help of oxygen

B. Glycolysis and the Krebs cycle connect to many other metabolic pathways

VI. Photosynthesis in Nature

A. Plants and other autotrophs are the producers of the biosphere

B. Chloroplasts are the sites of photosynthesis in plants

VII. The Pathways of Photosynthesis

A. The light reactions and the Calvin cycle cooperate in converting light energy to chemical energy of food

B. the light reactions transform solar energy to the chemical energy of ATP and NADPH

C. The Calvin cycle uses ATP and NADPH to convert CO2 to sugar

D. Alternative mechanisms of carbon fixation have evolved in hot, arid climates

Content Objectives

Carbohydrates Serve as Fuel and Building Material

1.Distinguish between monomers and polymers and apply this concepts to types of macromolecules

2.Draw diagrams to illustrate dehydration and hydrolysis reactions.

3. .Distinguish among monosaccharides, disaccharides, and polysaccharides.

4.Describe the formation of a glycosidic linkage.

5. .Distinguish between the glycosidic linkages found in starch and cellulose. Explain why the difference is biologically important. Think structure and function.

6.Explain why, in terms of how enzymes work, animals do not directly digest cellulose and why animals such as termites and cows can get energy from this molecule.

Metabolism, Energy and Life

  1. Distinguish between anabolic and catabolic pathways in cellular metabolism
  2. Distinguish between kinetic energy and potential energy and give examples of each that are important to biological systems
  3. Explain the 1st and 2nd law of Thermodynamics in your own words
  4. Explain why highly ordered living organisms do not violate the Second Law of Thermodynamics
  5. Distinguish between exergonic and endergonic reactions in terms of free energy changes and spontaneity
  6. Describe what is occurring if a chemical reaction reaches equilibrium.
  7. What are 3 kinds of cellular work.
  8. Describe the function of ATP in a cell
  9. list the three components of ATP and identify the major class of macromolecules to which it belongs
  10. Explain how ATP can perform cellular work using a phosphorylated intermediate.

Principles of Energy Conservation

  1. describe the overall summary equation for cellular respiration
  2. Define oxidation and reduction and explain why these reaction always occur in pairs
  3. explain how exergonic oxidation of glucose is coupled to endergonic synthesis of ATP
  4. explain how redox reactions are involved in energy exchanges
  5. distinguish between substrate-level and oxidative phosphorylation
  6. define coenzyme and list those involved in respiration

The Process of Cellular Respiration

  1. Explain why ATP is required for the preparatory steps of glycolysis
  2. Describe how the carbon chain of glucose changes as it proceeds through glycolysis
  3. Identify where in glycolysis that sugar oxidation, substrate-level phosphorylation, and reduction of co-enzymes occurs
  4. write a summary equation for glycolysis and describe where in the cell it occurs
  5. describe where pyruvate is oxidized to acetyl CoA, what molecules are produced and how it links glycolysis to the Krebs cycle
  6. Describe the location, molecules in and molecules out for the Krebs cycle
  7. explain at what point during cellular respiration glucose is completely oxidized
  8. describe the process of chemiosmosis
  9. explain how membrane structure is related to membrane function in chemiosmosis

Related metabolic Processes

  1. describe the fate of pyruvate in the absence of oxygen
  2. explain why fermentation is necessary
  3. describe how food molecules other than glucose can be oxidized to make ATP

Photosynthesis in Nature

  1. Distinguish between Autotrophic and heterotrophic nutrition
  2. distinguish between photosynthetic autotrophs and chemosynthetic autotrophs
  3. describe the location and structure of the chloroplast
  4. explain how chloroplast structure relates to its function

The Pathways of Photosynthesis

  1. Write a summary equation for photosynthesis
  2. explain the role of redox reactions in photosynthesis
  3. describe the relationship between and action spectrum and an absorption spectrum
  4. explain why the absorption spectrum for chlorophyll differs from the action spectrum for photosynthesis
  5. list the wavelengths of light that are most effective for photosynthesis
  6. Explain what happens when chlorophyll or accessory pigments absorb photons
  7. list the components of a photosystem and explain their function
  8. trace electron flow through photosystems II and I
  9. compare cyclic and noncyclic electron flow and explain the relationship between these components of the light reactions
  10. summarize the light reactions with an equation and describe where they occur
  11. describe important differences in chemiosmosis between oxidative phosphorylation in mitochondria and photophosphorylation in chloroplasts
  12. summarize the carbon-fixing reactions of the Calvin cycle and describe changes that occur in the carbon skeleton of the intermediates
  13. describe the role of ATP and NADPH in the Calvin cycle
  14. describe what happens to rubisco when the O2 concentration is much higher than CO2
  15. describe the major consequences of photorespiration
  16. describe two important photosynthetic adaptations that minimize photorespiration
  17. describe the fate of photosynthetic product