Biology Chapter 6

Fat is the most efficient molecule for long-term energy storage even compared to carbohydrates because _____.

with their numerous hydrogen atoms, fats provide an abundant source of high-energy electrons

We inhale O2 and we exhale CO2. Carbon dioxide is produced _____.

In the reaction that creates acetyl CoA (coenzyme A) from pyruvate

Given the relatively modest number of calories burned by anything but the most vigorous activities, why can people consume over 2,000 kilocalories a day, yet maintain a healthy body weight?

Most of the energy consumed in food is spent maintaining the body's functions, so only a fraction of food energy needs to be burned in exercise.

During fermentation, __________ that was produced during glycolysis is converted back to __________.

NADH; NAD+

Recent data suggests that heat-generating brown fat is most active in __________.

babies or lean people exposed to cold temperatures

Using the ATP generated during cellular respiration, the intermediates of glycolysis and the citric acid cycle, such as pyruvate and acetyl CoA, can be siphoned off and used to __________.

build amino acids, fats, and sugars

Each turn of the citric acid cycle generates one ATP and ___ additional energy-rich molecules: __________.

four; 3 NADH and 1 FADH2

When a car engine burns gasoline, the results of the reaction are similar to when cells burn glucose. Both reactions release carbon dioxide and water. In cells, the chemical energy in food is converted to ATP and heat. In a moving car, the chemical energy in gasoline is converted to _____.

kinetic energy and heat

A molecule that functions as the electron donor in a redox reaction __________.

loses electrons and becomes oxidized

In cellular respiration, glucose _____ electrons, whereas _____ electrons.

loses... oxygen gains

Lungs are to breathing as _____ are to cellular respiration.

mitochondria

A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes?

mitochondrial matrix

Some human cells, such as nerve cells, are restricted to aerobic respiration to recycle NADH and FADH2. If these cells are deprived of oxygen, then _____.

oxidative phosphorylation would come to a halt because there wouldn't be any oxygen to "pull" the electrons down the transport chain

In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to _____.

pump protons (H+) across the mitochondrial membrane

Glycolysis is the only stage of cellular respiration that _____.

requires ATP to make ATP

Sunlight is essential for the varied life on Earth. Sunlight provides energy to photosynthetic organisms by providing __________.

the energy necessary to power the rearrangement of chemical bonds in H2O and CO2

Oxidative phosphorylation could not occur without glycolysis and the citric acid cycle, because _____

these two stages supply the electrons needed for the electron transport chain