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| 1 | |
The electron transport chain is located:
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| | A) | On the outside of the cell membrane
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| | B) | Within the nucleus
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| | C) | Within the mitochondria
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| | D) | Within the cytoplasm
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| | E) | In lysosomes
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| 2 | |
Anaerobes have great difficulty surviving in an environment containing:
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| | A) | Oxygen
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| | B) | Nitrogen
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| | C) | Argon
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| | D) | Carbon dioxide
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| | E) | Water
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| 3 | |
Electrons are passed from enzyme to enzyme along the ETC in the direction of:
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| | A) | Decreasing entropy
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| | B) | Decreasing oxidation potential
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| | C) | Increasing EE |
| | D) | Glycolysis
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| | E) | The glyoxalate pathway
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| 4 | |
Both cyanide ion and hydrogen cyanide gas are highly toxic, blocking the movement of electrons through the ETC. Victims of cyanide poisoning often display rictus, a gaping grimace as though they were trying to take a bite out of the air. One reason why they might do this is:
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| | A) | The body senses that too much oxygen is available and compensates by hyperventilating
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| | B) | The body senses that too little ATP is available
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| | C) | Excess pyruvic acid accumulates and shuts down glycolysis by a feedback mechanism
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| | D) | Excess carbon dioxide results in a respiratory acidosis, with plasma pH falling below 7.35
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| | E) | Lack of movement of electrons through the ETC produces the same symptoms as oxygen deficiency
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| 5 | |
In order to generate ATP, cells need a high concentration of protons:
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| | A) | Inside the mitochondrial matrix
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| | B) | Within lysosomes
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| | C) | Outside the TCA cycle
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| | D) | Outside the mitochondrial matrix
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| | E) | Surrounding the cristae
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| 6 | |
Persons suffering angina (chest pain associated with cardiac problems) sometimes place a small pill containing some nitroglycerine under their tongue. The nitroglycerine decomposes, and a small amount of a substance is produced which lowers blood pressure, relieving angina. The substance is:
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| | A) | NO
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| | B) | HCN
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| | C) | H2S
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| | D) | H2O
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| | E) | CO2 |
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| 7 | |
If not otherwise dangerous, uncouplers would make good diet aids because:
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| | A) | They don't take part in the ETC
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| | B) | They don't block any other reactions
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| | C) | They lower redox potential
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| | D) | They are very inexpensive
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| | E) | They allow protons to pass through the mitochondrial membrane without ATP synthase
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| 8 | |
Vitamin C has long been known to be protective against scurvy, and even now, there are probably very important uses for vitamin C that we are unaware of. Vitamin C owes at least some of its value to the fact that it is an antioxidant. This means that vitamin C itself is:
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| | A) | An oxidizing agent
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| | B) | An acid
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| | C) | A base
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| | D) | A reducing agent
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| | E) | A blocker of the electron transport chain which results in the loss of a great many electrons
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| 9 | |
Those tiny lollipop-shaped structures seen in the early micrographs of mitochondrial membranes turned out to be:
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| | A) | Miniature water towers providing high osmotic pressure
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| | B) | Chemiosmotic electron pumps
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| | C) | ATP synthase
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| | D) | Pores in the mitochondrial matrix
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| | E) | Contact proteins which allow ions or molecules in true solution to pass through the membrane
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| 10 | |
Destruction of bacteria engulfed in a phagolysosome depends on oxidizing agents such as one which may be present in household bleach. Which one?
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| | A) | Detergents
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| | B) | Hypochlorous acid
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| | C) | Lye
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| | D) | Lime
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| | E) | Lysozyme
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| 11 | |
If it were possible to use thermogenin safely and therapeutically, it might be very useful for those who:
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| | A) | A Wanted to learn biochemistry without studying
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| | B) | Wished to gain weight
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| | C) | Were too warm during the summer
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| | D) | Wanted to lose weight
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| | E) | Were suffering from insomnia
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| 12 | |
In order for mitochondria to oxidize NADH and FADH2, there must be an adequate supply of:
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| | A) | ADP and phosphoric acid
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| | B) | ATP and pyrophosphoric acid
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| | C) | Glucose and AMP
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| | D) | AMP and ADP
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| | E) | ATP and glucose
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| 13 | |
The interior of the inner mitochondrial membrane is relatively impermeable to ionic substances because:
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| | A) | The membrane itself is ionic
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| | B) | The membrane is relatively polar
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| | C) | The outer portions of the membrane nearest the cytoplasm or mitochondrial matrix are relatively polar
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| | D) | The inside of the membrane is filled with water
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| | E) | The inside portion of the membrane is a lipid bilayer and relatively nonpolar
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| 14 | |
If you wanted to explain how ATP synthase works, you might describe it as:
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| | A) | A flat panel with tiny holes
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| | B) | A sliding panel with occasional hooks
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| | C) | A rotating shaft which forces ADP and phosphate closely together
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| | D) | A small fire
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| | E) | A tiny cellular battery
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| 15 | |
Both Marco Polo in his historic travels to China and ranchers in Western Nebraska and Eastern Wyoming suffered livestock losses due to toxic levels of selenium in plants. One route of absorption of selenium might be its incorporation in amino acids in the plant, and later release of the selenium upon digestion and metabolism of the amino acids. Which amino acid might be a good candidate to carry the selenium?
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| | A) | Glycine
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| | B) | Cysteine
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| | C) | Tryptophan
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| | D) | Alanine
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| | E) | Lysine
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| 16 | |
Electrons can be carried by iron or copper ions which serve as prosthetic groups for redox enzymes. We could describe these ions as:
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| | A) | Coenzymes
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| | B) | Cofactors
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| | C) | Allosteric inhibitors
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| | D) | Noncompetitive inhibitors
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| | E) | Opposite attractors
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| 17 | |
Mitchell's chemiosmotic theory suggested that a high concentration of protons outside the mitochondrial membrane:
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| | A) | Reduced the oxidation potential
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| | B) | Made the interior of the membrane highly acidic
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| | C) | Caused the exterior of the membrane to become highly basic
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| | D) | Generated a voltage which helped drive the ATP synthase
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| | E) | Generated a low electrical potential which caused protons to exit the mitochondria
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| 18 | |
You'd expect mitochondria to generate ATP if they had:
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| | A) | A ready supply of ADP and phosphate and were placed in acidic solution
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| | B) | A ready supply of ADP and phosphate and were placed in basic solution
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| | C) | Plenty of glucose and AMP
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| | D) | An ample supply of water and were placed in a soap solution
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| | E) | Fructose, glucose, lactose, and AMP
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| 19 | |
The mechanism of damage done by free radicals (now called reactive oxygen species) to both physiological systems and to mechanical substances is still not fully understood, but the danger posed is substantial. ROSs are implicated in nasty processes from polymerization of gasoline to formation of varnishes which clog carburetors and injectors to formations of plaque which may cause clogged arteries. Producers of foodstuffs worry about ROSs causing premature spoilage of foods, and often include free radical scavengers. Even some fitness waters contain free radical scavengers. Examine a box of cereal and find the antioxidant labeled there: |
| | A) | Vitamin B |
| | B) | Riboflavin |
| | C) | Thiamine pyrophosphate |
| | D) | BHA (butylated hydroxyanisole) or its cousin BHT (butylated hydroxytoluene) |
| | E) | Benzene |
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| 20 | |
Dentists often examine the mouths of patients for signs of acatalasemia. In this illness, hydrogen peroxide produced by bacteria may oxidize the Fe+2 of hemoglobin to Fe+3, forming methemoglobin, which does not carry oxygen as well. Ordinarily, we are protected from this danger by the enzyme:
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| | A) | Glutathione peroxidase
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| | B) | Superoxide dismutase
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| | C) | Catalase
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| | D) | Transaminase
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| | E) | Glucose-6-phosphate dehydrogenase
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| 21 | |
Erythrocytes are fragile and may be damaged by illnesses such as hemolytic anemia, resulting in dark-colored urine. Normally, the erythrocytes are protected by:
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| | A) | Reduced glutathione
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| | B) | Reduced cystine
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| | C) | Oxidized glutathione
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| | D) | Hydrogen peroxide
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| | E) | Superoxide dismutase
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| 22 | |
Brown fat is so-called because of the presence of:
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| | A) | Hemoglobin
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| | B) | Porphyrin compounds
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| | C) | Urobilinogen
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| | D) | Mitochondria
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| | E) | Dark meat
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| 23 | |
Gramicidin A reduces the amount of energy bacterial cells can derive from the ETC. Gramicidin A could best be characterized as a/an:
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| | A) | Oxidoreductase
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| | B) | Ionophore
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| | C) | Collapser
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| | D) | Spoiler
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| | E) | Uncoupler
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