Week 3-4 Study Guide

Metabolism Study Guide

Metabolism is going to be one of the most complex sections we cover this quarter! BREATHE--it's long because it covers several lectures.
Please review the study guide carefully and ask Dr. Y questions if needed! Also note that we covered metabolism over two weeks so the content is spread out across many classes/pre-lectures.

Terms you should know:

Metabolism	Anabolism	Catabolism	Catalyst	ADP	ATP
NADH/NAD+; FADH/FADH2	Electron carrier	glycolysis	Krebs cycle	Photosynthesis	Pyruvate
Glucose	Aerobic	Anaerobic	Electron transport chain	Proton pumps	Chemiosmotic gradient
Proton motive force	Fermentation	Chemotroph	Autotroph	Phototroph	Heterotroph
Acidophile	Mesophile	Psychophile	Psychotroph	Thermophile	Osmotic pressure
Plasmolysis	Obligate haplophile	Facultative haplophile	Obligate aerobe	Facultative anaerobe	Obligate anaerobe
Aerotolerant anaerobe	Microaerophile	SOD	catalase	Reduction	oxidation

 

You should be able to explain the following in your own words:

Part 1: Cell respiration

• When a molecule is oxidized, what has happened to it? Does it have more or less stored energy than before it was oxidized?
• When a molecule is reduced, what has happened to it? Does it have more or less stored energy than before it was reduced?
• What type of chemical reaction (endergonic or exergonic and synthesis or decomposition) best
  represents catabolism?
• What type of chemical reaction best represents anabolism?
• Explain why metabolic reactions are typically stepwise reactions.
• How does an enzyme act as a biological catalyst? Why are enzymes specific to their substrates?
• Where is energy stored on ATP? How is that stored energy released? Where does the energy come from to make ATP in the cell?
  
  
  
• What are the biological electron acceptors? Which ones act in glycolysis? Krebs cycle?
  
• Which molecule has more stored energy: NADH or NAD+? Explain your answer.
• What is the difference between an aerobe and an anaerobe? What is the end electron acceptor for an aerobe? Give some examples of possible final electron acceptors for anaerobes.
• Which molecule has more stored energy: Glucose, 2 molecules of pyruvate or two molecules of
  lactic acid? Explain your answer.
• What are the starting molecules of glycolysis and what are the resulting products? What would happen to glycolysis if there was no NAD+ in the cell? Is ATP used? Is ATP produced?
• What happens during the Krebs cycle? How is energy transferred during the Krebs cycle? Is ATP used? Is ATP produced?
• Where is the electron transport chain located in prokaryotes? Eukaryotes?
• Describe the structure of the mitochondria. Where are the proton concentrations high? Where are they low?
• Describe the electron transport chain in eukaryotes. Describe the method for forming a chemiosmotic gradient of H+ (protons) What is the proton motive force? How does the proton motive force lead to the production of ATP?
• Explain how fermentation differs from cellular respiration. Describe the steps of lactic acid fermentation. Describe the steps of alcohol fermentation.
• Explain why fermentation yields so much less ATP than cellular respiration by comparing the energy contained in the products of fermentation to the products of cellular respiration.
• What are the enzymes that break down proteins called and what is the result of this breakdown? What must happen to an amino acid before it can be used to make ATP?
• What are the enzymes that break down lipids called and what is the result of this breakdown? Where do the products of lipid breakdown enter into cellular respiration?
• Explain the difference between chemotrophs and phototrophs and between heterotrophs and autotrophs. Identify the energy and carbon source for the following: photoheterotrophs, photoautotrophs, chemoheterotrophs, chemoautotrophs.
  
  Part 2
• Why are acidic foods easier to preserve than neutral pH foods?
• Define the following terms: mesophile, psychrophile, psychrotroph, thermophiles, extreme thermophiles.
• What is the difference between the minimum growth temperature, the maximum growth temperature and the optimum growth temperature? Speculate why
  bacteria stop growing after the temperature exceeds the maximum growth temperature.
• Why is refrigeration a good strategy for food preservation? For pathogen control? Why do foods still spoil in the refrigerator?
• Why is salt an excellent preservative. What structure on a bacteria helps to maintain cell shape in conditions of high or low salt concentration?
• Why do living organisms require nitrogen and where do they get it? What is nitrogen fixation? Why do living organisms require phosphorus and where do they get it?
• Explain how oxygen can be toxic to the cell and describe how it causes damage. Describe how SOD and catalase works to neutralize toxic forms of oxygen.
• Describe how catalase works to neutralize hydrogen peroxide.
• Speculate on whether the following organisms have SOD and catalase and explain why: facultative anaerobes, obligate anaerobes, aerotolerant anaerobes, microareophiles. Where do each of these grow in a thioglycolate tube? What are the oxygen levels along a thioglycolate tube?
  

 

Extra resources:

• A realistic version of ETC transportLinks to an external site. (Video), a bit advanced in terms of details but cool to watch