Cellular Respiration
How much ATP can a cell make from one glucose molecule in the absence of oxygen?
2 ATP
When pyruvic acid is converted to acetyl CoA, __________.
CO2 and NADH are formed
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 __________.
lactic acid
If humans did not breathe in O2, we would not __________.
make enough ATP to meet our energy requirements
The energy given up by electrons as they move through the electron transport chain is used to __________.
pump H+ through a membrane
Immediately after completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.
NADH
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Only autotrophs can live on nutrients that are entirely inorganic.
Which one of the following statements best describes the relationship between photosynthesis and cellular respiration?
Photosynthesis stores energy in organic molecules, and cellular respiration releases it.
Why is the citric acid cycle called a cycle?
The two-carbon acetic acid binds to a four-carbon molecule that is restored at the end of the cycle to be used again in the citric acid cycle.
Most of the electrons released from glucose by cellular respiration __________.
are bound to NAD+ to be sent through electron transport
During aerobic respiration, molecular oxygen (O2) is used __________.
at the end of the electron transport chain to accept electrons and form H2O
Some microorganisms that live around hydrothermal vents in the deep ocean use inorganic energy sources and compounds to produce their own food. Therefore, these organisms are considered to be __________.
autotrophs
In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and in a few minutes radioactive oxygen atoms showed up in __________.
carbon dioxide
Which one of the following is the source of the energy that pumps hydrogen ions across the inner mitochondrial membrane?
electrons
Fermentation is essentially glycolysis plus an extra step in which pyruvic acid is reduced to form lactic acid or alcohol and carbon dioxide. This last step __________.
enables the cell to recycle NAD+
The major (but not sole) accomplishment of the citric acid cycle in the production of energy-carrying molecules is the __________.
formation of NADH and FADH2
Of the metabolic pathways listed below, the only pathway found in almost all organisms is __________.
glycolysis
A chemist has discovered a drug that blocks an enzyme that catalyzes some of the reactions of glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because __________.
human cells also perform glycolysis; the drug might also poison them
The ATP synthase in a human cell gets energy for making ATP directly from __________.
the flow of H+ through a membrane
When a poison such as rotenone blocks the electron transport chain, glycolysis and the citric acid cycle soon grind to a halt as well because __________.
they run out of NAD+ and FAD
