bio cellular respiration and circulation and gas exchange.
The maximum amount of air a person can exhale, after maximal inhalation, is called __________.
Vital capacity
WHAT IF? During intense exercise, can a muscle cell use fat as a concentrated source of chemical energy?
When oxygen is present, the fatty acid chains containing most of the energy of a fat are oxidized and fed into the citric acid cycle and the electron transport chain. During intense exercise, however, oxygen is scarce in muscle cells, so ATP must be generated by glycolysis alone. A very small part of a fat molecule, the glycerol backbone, can be oxidized via glycolysis, but the amount of energy released by this portion is insignificant compared with that released by the fatty acid chains. (This is why moderate exercise, staying below that 70% maximum heart rate, is better for burning fat- because enough oxygen remains available to the muscles.)
When might your body synthesize fat molecules?
When you consume more food than necessary for metabolic processes, your body synthesizes fat as a way of storing energy for later use.
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step __________.
enables the cell to recycle the reduced NADH to oxidized NAD⁺.
Which of the following is the main factor that causes lymph to move through lymphatic vessels?
Contractions of body muscles near lymph vessels
Gas exchange in the gills of a bony fish is maximized by which of the following?
Countercurrent exchange
WHAT IF? If the following redox reaction occurred, which compound would be oxidized? Which reduced? C₄H₆O₅+NAD⁺→C₄H₄O₅+NADH+H⁺
C₄H₆O₅ would be oxidized, and NAD⁺ would be reduced.
A mutation that results in a nonfunctioning nitric oxide receptor would cause __________.
Decreased vasodilation
WHAT IF? In the absence of O2, as stated in question 1, what do you think would happen if you decreased the pH of the intermembrane space of the mitochondria? Explain your answer
Decreasing the pH means the addition of H+. This would establish a proton gradient even without the function of the electron transport chain, and we would expect ATP synthase to function and synthesize ATP.
In the absence of O₂, what would happen if you decreased the pH of the intermembrane space of the mitochondrion?
Decreasing the pH means the addition of H+. This would establish a proton gradient even without the function of the electron transport chain, and we would expect ATP synthase to function and synthesize ATP. (In fact, it was experiments like this that provided support for chemiosmosis as an energy-coupling mechanism.)
In the alveoli and lung capillaries, carbon dioxide and oxygen are exchanged by means of __________.
Diffusion
What would you expect to see in an individual with low levels of blood protein in the capillaries?
Edema in the body tissues
Which of the following best describes the electron transport chain?
Electrons are passed from one carrier to another, releasing a little energy at each step.
Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?
Electrons moving down the electron transport chain
The primary sealant(s) that plug(s) leaks in damaged blood vessels is/are __________.
Fibrin
In which animal does the circulatory system include a heart and a system of closed vessels?
Fish
Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle?
Formation of NADH and FADH₂.
How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?
Four.
Which respiratory organ, used for gas exchange, is most often found only in fully aquatic animals?
Gills
In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.
Glucose.... Oxygen
Of the metabolic pathways listed below, which is the only pathway found in all organisms?
Glycolysis.
Which metabolic pathway is common for both fermentation and cellular respiration of a glucose molecule?
Glycolysis.
What causes atherosclerosis which is one of the leading causes of heart attacks?
Hardening of the arteries by accumulation of fatty deposits
The function of cellular respiration is to __________.
Harvesting usable energy from glucose
Pulse is a direct measure of...
Heart Rate
Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a....
Higher PO₂
What causes CO2 in the blood to decrease?
Hyperventilation
What is the physiological cause of a heart attack?
A blood clot lodging in a blood vessel supplying the heart
Which of the following would increase the release of oxygen from red blood cells?
A decrease in pH and a decrease in the PO2
What happens when the CO2 level from cellular respiration increases in the blood?
A decrease in the pH of the cerebrospinal fluid triggers the brain's breathing control centers, which stimulate diaphragm and rib muscle contractions.
Consider the NADH formed during glycolysis. What is the final acceptor for its electrons during fermentation? What is the final acceptor for its electrons during aerobic respiration?
A derivative of pyruvate, such as acetaldehyde during alcohol fermentation, or pyruvate itself during lactic acid fermentation; oxygen during aerobic respiration
All known birds and mammals have __________.
A double circulatory system and a four-chambered heart
For a body surface to be a respiratory surface, it must __________.
Be thin and moist
Compare and Contrast aerobic and anaerobic respiration.
Both processes include glycolysis, the citric citric cycle, and oxidative phosphorylation. In aerobic respiration, the final electron acceptor is oxygen (O₂); in anaerobic respiration, the final electron acceptor is a different substance.
What processes in your cells produce the CO₂ that you exhale?
CO2 is released from the pyruvate that is the end product of glycolysis, and CO2 is also released during the citric acid cycle.
In an experiment, mice were fed glucose (C₆H₁₂O₆) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in __________.
Carbon dioxide.
The function of the pulmonary circuit in a dog is to __________.
Carry carbon dioxide to the lungs and pick up oxygen from the lungs
How is the flow of hemolymph through an open circulatory system similar to the flow of water through and outdoor fountain?
In both open circulatory system and a fountain, fluid is pumped through a tube and then returns to the pump after collecting in a pool
During respiration in eukaryotic cells, the electron transport chain is located in or on the __________.
Inner membrane of the mitochondrion
Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose?
It is converted to heat.
What is unique about blood in pulmonary arteries compared with blood in other arteries?
It is loaded with carbon dioxide. It has not been oxygenated yet.
Heart valves function to __________.
Keep blood moving forward through the heart
Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds?
Lactate.
Blood returning to the mammalian heart in the plumonary vein drains first into the...
Left Atrium
Which chamber(s) of a human heart receive(s) and pump(s) oxygenated blood?
Left ventricle and left atrium
A molecule becomes more oxidized when it...
Loses an Electron.
Countercurrent exchange in the gills of a fish __________.
Maintains a gradient that enhances diffusion
Name the molecules that conserve most of the energy from redox reactions of the citric acid cycle. How is this energy converted to a form that can be used to make ATP?
NADH and FADH2; they will donate electrons to the electron transport chain.
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.
NADH.
In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?
NAD⁺
What is the order of passage as air is inhaled during ventilation of the lungs in a typical mammal?
Nasal cavity, pharynx, larynx, trachea, bronchus, bronchiole, & alveolus
In a fish, blood circulates through __________, whereas in a mammal, it circulates through __________.
One circuit ... two circuits
MAKE CONNECTIONS Membranes must be fluid to function properly (as you learned in Concept 5.1). How does the operation of the electron transport chain support that assertion.
One of the components of the electron transport chain, Ubiquinone (Q), must be able to diffuse within the membrane. It could not do so if the membrane components were locked rigidly into place.
Membranes must be fluid to function properly. how does the operation of the electron transport chain support that assertion?
One of the components of the electron transport chain, ubiquinone (Q), must be able to diffuse within the membrane. It could not do so if the membrane components were locked rigidly into place.
Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?
Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
What effect would an absence of O₂ have on chemiosmosis?
Oxidative phosphorylation would eventually stop entirely, resulting in no ATP production by this process. Without oxygen to "pull" electrons down the electron transport chain, H+ would not be pumped into the mitochondrion's intermembrane space and chemiosmosis would not occur.
Most of the ATP produced in cellular respiration comes from which of the following processes?
Oxidative phosphorylation.
During the reaction C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O, which compound is reduced as a result of the reaction?
Oxygen
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is...
Oxygen.
In mitochondria, exergonic redox reactions...
Provide the energy that establishes the proton gradient.
In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?
Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce a NAD⁺ to an NADH.
What is the oxidizing agent in the following reaction? Pyruvate+NADH+H⁺→Lactate+NAD⁺
Pyruvate.
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?
Reducing NAD⁺ to NADH on glycolysis and the citric acid cycle and producing a proton gradient for ATP synthesis in the mitochondria.
Muscle tissues make lactate from pyruvate to do which of the following?
Regenerate NAD⁺.
Blood leaves the inferior vena cava and flows directly into the __________.
Right atrium
The SA node generates an electrical impulse from its location in the __________.
Right atrium, causing atrial contraction
If resistance increases in the capillary beds of the lung, which structure would be affected first?
Right ventricle
When you hold your breathe, which of the following blood gas changes first leads to the urge to breathe?
Rising CO₂
When you hold your breath, which of the following blood gas changes leads initially to the urge to breathe again?
Rising carbon dioxide concentration
Name and describe two ways which ATP is made during cellular respiration. During what stage(s) in the process does each type occur?
Substrate-level phosphorylation, which occurs during glycolysis and the citric acid cycle, involves the direct transfer of a phosphate group from an organic substrate to ADP by an enzyme. The process of oxidative phosphorylation occurs during the third stage of cellular respiration, which is called oxidative phosphorylation. In this process, the synthesis of ATP from ADP and inorganic phosphate (℗i) is powered by the redox reactions of the electron transport chain.
Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed?
Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.
Most CO₂ from catabolism is released during...
The Citric Acid Cycle.
Where do the reactions of glycolysis occur in a eukaryotic cell?
The Cytosol.
WHAT IF? A glucose-fed yeast cell is moved from an aerobic environment to an anaerobic one. How would its rate of glucose consumption change if ATP were to generated at the same rate?
The cell would need to consume glucose about 16 times the consumption rate in the aerobic environment. (2 ATP are generated by fermentation versus up to 32 ATP by cellular respiration).
If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop?
The chemiosmotic synthesis of ATP would stop in the mitochondria, but substrate-level phosphorylation could continue.
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?
The citric acid cycle
Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O₂) and produces CO₂?
The combination of the citric acid cycle and electron transport.
Make Connections Compare the structure of a fat (see 3.13) with that of a carbohydrate (see 3.8). What features of their structure make fat a better fuel?
The fat is much more reduced; it has many - CH2 - units, and in all these bonds the electrons are equally shared. The electrons present in a carbohydrate molecule are already somewhat oxidized (Share unequally in bonds), as quite a few of them are grounds to oxygen. Electrons that are equally shared, as in a fat, have higher energy levels than electrons that are unequally shared, as in carbohydrates. Thus, fats are much better fuels than carbohydrates
Why is the citric acid cycle called a cycle?
The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.
Which of the following decreases blood pressure?
Vasodilation
When we compare the structures and functions of arteries and veins, we find that the walls of arteries are __________, the blood pressure inside arteries is __________, and the blood in arteries is moving __________ the heart.
Thicker ... higher ... away from
Your blood pressure is 120/70. The "120" indicates __________, and the "70" indicates __________.
Arterial pressure during heart contraction ... arterial pressure during heart relaxation
During aerobic respiration, molecular oxygen (O₂) is used for which of the following purposes?
At the end of the electron transport chain to accept electrons and form H₂O.
Which of the following is a function of the circulatory system?
Transporting nutrients
Which of the following substances is/are involved in oxidative phosphorylation?
ADP, Oxygen, and ATP.
A patient with which of the following conditions would probably benefit by injections of purified multipotent stem cells?
AIDS, Leukemia, impaired resistance to infection, sickle-cell disease
A recording of the electrical activity of a patient's heart shows that the atria are contracting regularly and normally, but every few beats the ventricles fail to contract. Which of the following is probably functioning improperly?
AV node
An open circulatory system __________.
Allows interstitial fluid , called hemolymph, to mix freely with vascular fluid
Which structure in a human is most similar in function to the gill lamellae of a fish?
Alveoli
When protein molecules are used as fuel for cellular respiration, __________ are produced as waste.
Amino group.
Which of the following respiratory systems is not closely associated with a blood supply?
The lungs of a vertebrate
Which of the following is a function of erythrocytes (red blood cells)?
The main function of erythrocytes is the transport of oxygen.
Where do the reactions of the citric acid cycle occur in eukaryotic cells?
The matrix of the mitochondrion.
If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?
The muscle cells will have more trouble making enough ATP to meet their energy requirements. The cells will not be able to carry out oxidative phosphorylation. The cells will consume glucose at an increased rate.
Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced?
The name of the process that oxidizes glucose to pyruvate and produces ATP and NADH is glycolysis.
One feature that amphibians and humans have in common is...
The number of circuits for circulation.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
The pH of the matrix increases.
In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this?
The products of glycolysis contain the same total number of carbon atoms as in the starting material.
If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except...
The pulmonary vein.
Pressure is greatest in the ventricles when __________.
The ventricles contract
