Chapter 9 (Part 2)
Arrange the steps of ATP generation by ATP synthase in the order that they occur.
*Hydrogen ion gradient is established between the inter membrane space and the mitochondrial matrix *Hydrogen ions move down their gradient through a channel in ATP synthase *Hydrogen ions cause the F0 portion of ATP synthase to spin *Catalytic sites in the F1 portion of ATP synthase phosphorylate ADP
Cellular respiration is carried out in the presence of oxygen (aerobic conditions) or the absence of oxygen (anaerobic conditions). Determine whether each of the following occur under aerobic conditions, anaerobic conditions, or both aerobic and anaerobic conditions.
Aerobic conditions *electron transport chain Anaerobic conditions *citric acid cycle (Krebs cycle) Both *glycolysis
Identify compounds that are required for the electron transport chain and compounds that are produced by the electron transport chain. Not all the potential reactants or products are given. Place all the compounds.
Compounds that enter the electron transport chain *NADH *FADH2 *O2 *ADP Compounds produced by the electron transport chain *NAD+ *FAD *H2O *ATP
Compare and contrast lactic acid fermentation and ethanol fermentation (alcohol fermentation). Move each phrase to the appropriate category. If a phrase describes both types of fermentation, classify it as both.
Ethanol fermentation *used by yeast cells *generates ethanol Both *considered to be an anaerobic process *regenerates NAD+ that can be used in glycolysis Lactic acid fermentation (alcohol fermentation) *used by animal cells *produces lactic acid (lactate)
A proton gradient is formed in the mitochondria such that the concentration of protons (H ) is higher on one side of the inner mitochondrial membrane than on the other side. What is the purpose of this proton gradient?
Generates ATP in the electron transport chain
Anaerobic respiration allows a cell to break down carbohydrates in the absence of oxygen. Identify how NAD is used by animal cells during anaerobic respiration.
Glycolysis requires NAD+ produced from fermentation to produce ATP
What is the function of the proton gradient in the mitochondrion?
It is potential energy that the cell uses to generate ATP
Mankind has used lactic acid fermentation and alcohol fermentation for its own advantage since the beginnings of civilization. Bacteria produce the lactic acid used in food production. Lactic acid typically causes a sour taste in food. It can also cause a thicker texture in fermented dairy products. Fermentation by yeasts generates ethanol and carbon dioxide (CO2). Ethanol is a type of alcohol that causes intoxication when consumed. Carbon dioxide produced by ethanol fermentation allows some foods to take on a lighter, or less dense, texture. Which type of fermentation is used in the production of the following foods?
Lactic acid fermentation *Cheese *Sauerkraut (fermented cabbage) Alcohol fermentation *Hard cider *Bread
Osmosis is the movement of water across a semipermeable membrane from a region of low to high solute concentration. Considering the definition of osmosis, which of the following statements describe chemiosmosis?
Movements of ions across a semipermeable membrane from a region of high to low ion concentration
Classify each description or example as describing facultative anaerobes, obligate anaerobes, or both.
Obligate anaerobes *unable to use oxygen for aerobic respiration *may be poisoned by oxygen *a bacteria species that produces ATP by fermentation only Facultative anaerobes *able to change from aerobic to anaerobic respiration or fermentation if oxygen becomes unavaible *use oxygen for aerobic respiration if oxygen is available *a bacteria species capable of aerobic respiration and fermentation Both *capable of growing in the absence of oxygen *capable of producing ATP without oxygen