Chapter 6: How Cells Harvest Chemical Energy

True or false: The transfer of H atoms from glucose to oxygen does not represent redox reactions. If false, make it a correct statement.

False, it does represent redox reactions, as oxygen gas is reduced.

True or false: Blood traveling from your leg muscle to the lungs would be high in oxygen. If false, make it a correct statement.

False, it would be low in oxygen.

True or false: A substance that makes the inner mitochondrial membrane leaky to H1 (H1 would be able to leak across the membrane at points other than ATP synthase) increases ATP production in mitochondria. If false, make it a correct statement.

False, it would decrease ATP production as ATP synthase efficiency would be reduced.

You are taking a road trip from Chicago to Denver. The trip is going to take roughly 15 hours. At the start of your trip, you get a 96-oz Mega Gulp from 11-seven of Mountain Mist. This beverage will have roughly 1,360 kcal. How long into your trip will you have burned the calo- ries from this drink? Refer to Figure 6.4 in your textbook on page 91.

It would actually take longer than your trip, a bit over 22 hours.

Briefly explain why a teeter-totter is a good analogy for describing how reductions and oxida- tions always go together.

It's a good analogy because, for every reduction, there is an oxidation, and vice versa. This is similar to a teeter-totter. When one side goes up, the other has to go down.

If you opened a wine vat, would the yeast inside continue to perform alcoholic fermentation? Briefly explain your answer with some details about what would happen.

No, because they would be exposed to atmospheric oxygen and they would preferentially perform aerobic respiration.

Plants release what gaseous by-product as a result of photosynthesis?

O2

CO2 is a gaseous by-product of cellular respiration that you exhale with each breath. Briefly explain where the CO2 comes from.

The CO2 comes from the organic molecules (food) that you consume and is a by-product of cellular respiration.

The overall chemical equation for cellular respiration is: C6H12O6 + 6O2 ->->->-> 6CO2 + ^H2O Briefly explain why the equation has multiple arrows.

The arrows represent the fact that cellular respiration consists of multiple chemical reactions.

A buildup of ____________ initiates the inhibition of an enzyme that functions early in glycolysis.

ATP

What uses the energy found within a proton gradient to drive the syn- thesis of ATP?

ATP synthase

What initial observation led scientists to hypothesize that brown fat may be activated by cold temperatures?

Brown fat tissue was found at higher levels when the scans were taken during cold weather.

In lactic acid fermentation, __________ becomes the target of reduction by NADH.

pyruvate

The only portion of cellular respiration that is cyclic is?

the citric acid cycle

Students frequently have the misconception that plant cells don't perform cellular respiration. Briefly explain the basis of this misconception.

This misconception arises because plant cells perform photosynthesis, which creates the assumption that plant cells do not perform cellular respiration.

True or false: Brown fat contains mitochondria. If false, make it a correct statement.

True

True or false: Glycolysis and the citric acid cycle both function as metabolic interchanges where the products of their chemical reactions can also be used for biosynthesis. If false, make it a correct statement.

True

The formation of NaCl (table salt) involves an atom of Na giving an electron to an atom of Cl.

a. This would be considered a redox reaction. b. Na got oxidized. c. Cl got reduced. d. All of the above are true statements regarding the formation of NaCl.

Fermentation is essentially glycolysis because glycolysis does not require _________________ to function.

oxygen

The driving force behind oxidative phosphorylation is?

oxygen

Fats are hydrophobic and carbohydrates are hydrophilic. Use this information to explain why humans store the majority of their excess energy as fat and not carbohydrates.

Because fat will not require water for storage

Input of cellular respiration is O2 + C6H12O6 What is the Output?

CO2+H2O

What is always lost during photosynthesis and cellular respiration?

Energy

What generates fewer molecules of ATP because it contributes its electrons further along the electron transport chain?

FADH2

List two sources of evidence that indicate glycolysis is extremely old.

Glycolysis is universal, and it does not occur within a membrane-bound organelle.

Which of the following is the correct order of the main stages of cellular respiration?

Glycolysis, citric acid cycle, oxidative phosphorylation

How are photosynthesis and cellular respiration linked on a molecular level?

They are linked in that the products of one are the reactants of the other.

What must proteins be broken down into before they can be burned as energy? Refer to Figure 6.15 on page 102 in your textbook.

They must be broken down into amino acids

Any substance that inhibits the transportation of oxygen from the lungs affects what?

cellular respiration