Chapter 13

Glycolysis occurs in a series of 10 steps using 10 different enzymes. Place the following broad events that occur during glycolysis into their correct order. - the six carbon sugar is split into two smaller molecules -energy is invested by using up some ATP - two molecules of pyruvate are generated -energy is captured as ATP and NADH

1.) energy is invested by using up some ATP 2.) the six carbon is split into two smaller molecules 3.) energy is captured as ATP and NADH 4.) two molecules of pyruvate are generated

Assume 5 molecules of FADH2 are made in the citric acid cycle in a given amount of time. How many NADH are made during the same time interval?

15

Which molecules are required for the citric acid cycle to fully oxidize the carbons donated by acetyl CoA? choose one or more A.) GDP B.) ATP C.) O2 D.) GTP E.) NAD+ F.) oxaloacetate

A.) GDP C.) ATP E.) NAD+ F.) oxaloacetate

After an overnight fast, most of the acetyl CoA entering the citric acid cycle is derived from what type of molecule? A.) fatty acids B.) amino acids C.) glucose D.) glycogen E.) pyruvate

A.) fatty acids

When food is plentiful, animals can store glucose as what? A.) glycogen B.) glucose 6-phosphate C.) starch D.) glycogen or starch E.) acetyl CoA

A.) glycogen

Weight loss can occur when glucose is oxidized to CO2 rather than being stored as glycogen. The first step in glucose oxidation is glycolysis. A 1930s diet drug, DNP, made the inner mitochondrial membrane permeable to protons, increasing the rate of glycolysis. What is the explanation for the DNP-induced increase in glycolysis? A.) high ADP activates phosphofructokinase B.) DNP also makes the inner mitochondrial membrane leaky to glucose, increasing the ability of the mitochondria to perform glycolysis C.) high ATP activates phosphofructokinase D.) high AMP inhibits phosphofructokinase

A.) high ADP activates phosphofructokinase

The main regulatory step of glycolysis occurs in step 3. Choose all of the following that correctly describe some aspect of step 3 in glycolysis. A.) the reaction generates the product fructose 1,6-biphosphate B.) the enzyme that catalyzes step 3 is phosphofructokinase C.) the enzyme uses an ATP D.) the reaction is an irreversible reaction

All are correct

In cells, pyruvate can be converted to which of the following? choose one or more A.) lactate B.) glucose C.) oxaloacetate D.) acetyl CoA E.) alanine

All of the above

Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle? A.) ATP B.) NAD+ C.) FADH2 D.) ADP E.) NADH

B.) NAD+

Which statements below accurately describes an aspect of the citric acid cycle? A.) the two carbons that enter as acetyl CoA are released in the same cycle as CO2 B.) oxaloacetate is regenerated by the end of the citric acid cycle C.) NADH is generated in steps 3,4, and 8 D.) the citric acid cycle produces two kinds of high energy molecules, GTP and NADH

B.) oxaloacetate is regenerated by the end of the citric acid cycle C.) NADH is generated in steps 3,4, and 8

How do enzymes maximize the energy harvested from the oxidation of food molecules? A.) they allow what would otherwise be an energetically unfavorable oxidation reaction to occur B.) they allow the stepwise oxidation of food molecules, which releases energy in small amounts C.) they guarantee that each reaction involved in the oxidation of food molecules proceeds in just one direction D.) they allow a larger amount of energy to be released from food molecules such as glucose E.) they allow oxidation reactions to take place without an input of activation energy

B.) they allow the stepwise oxidation of food molecules, which releases energy in small amounts

Most of the energy released by oxidizing glucose is saved in the high-energy bonds of what molecules? A.) O2 B.) GDP and other activated carriers C.) ATP and other activated carriers D.) H2O and CO2 E.) ADP and other activated carriers

C.) ADP and other activated carriers

Which statement is true of glycogen phosphorylase? A.) it stimulates gluconeogenesis B.) it is inhibited by 6-phosphate, but activated by ATP C.) it is inhibited by glucose 6-phosphate and by ATP D.) it is activated by glucose 6-phosphate and by ATP E.) it is activated by glucose 6-phosphate, but inhibited by ATP

C.) it is inhibited by glucose 6-phosphate and by ATP

The NADH generated during glycolysis and the citric acid cycle feeds its high energy electrons to which of the following? A.) H2O B.) ADP C.) the electron transport chain D.) the citric acid cycle E.) FAD

C.) the electron transport chain

In eukaryotic cells, what is the final electron acceptor in the electron transport chain? A.) NAD+ B.) ATP C.) FADH2 D.) O2 E.) CO2

D.) O2

When ATP and food molecules such as fatty acids are abundant, which will occur? A.) when food molecules are plentiful, neither glycolysis nor gluconeogenesis will occur B.) enzymes involved in glycolysis will operate in the reverse direction, using pyruvate to produce glucose C.) enzymes involved in glycolysis will break down glucose to generate pyruvate D.) enzymes involved in gluconeogenesis will use energy to produce glucose E.) when food and ATP are plentiful, both glycolysis and gluconeogenesis will occur

D.) enzymes involved in gluconeogenesis will use energy to produce glucose

Under anaerobid conditions, which metabolic pathway regenerates the supply of NAD+ needed for glycolysis? A.) breakdown of amino acids B.) formation of acetyl CoA C.) breakdown of fats D.) fermentation E.) citric acid cycle

D.) fermentation

Which two-carbon molecule enters the citric acid cycle? A.) oxaloacetate B.) pyruvate C.) carbon dioxide D.) citrate E.) acetyl CoA

E.) acetyl CoA

In what form do plant and animal cells store fat? A.) glycogen B.) nitroglycerin C.) phospholipids D.) starch E.) triacylglycerol

E.) triacylglycerol

You're packing for a hiking trip during which you'll be burning a lot of calories with physical activity. You want to pack as efficiently as possible since you need to carry a tent and all your food. You can get the most calories out of 5kg of food if its stored in the form of:

fat

Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell? A.) cytosol B.) mitochondrion C.) endoplasmic reticulum D.) golgi apparatus

B.) mitochondrion

In the absence of oxygen, in cells that cannot carry out fermentation, glycolysis would halt which step? A.) the oxidation of gylceraldehyde 3-phosphate to 1,3-biphosphoglycerate B.) the transfer of a phosphate group from 1,3- biphosphoglycerate to ADP to form ATP C.) the reversible rearrangement of glucose 6-phosphate to fructose 6-phosphate D.) the phosphorylation of fructose 6-phosphate to fructose 1,6-biphosphate

A.) the oxidation of glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate

Your friends are on a low-fat, high-carbohydrate diet, which they claim will prevent fat accumulation within their bodies. They eat tons of pasta and bread without worrying about calorie count. What can you correctly say to your friends about their potential to accumulate lipids on their low-fat diet? A.) they will accumulate fats because cells have no way of storing carbohydrates B.) they will accumulate fats because cells can convert glycolytic metabolites into lipids C.) they will not accumulate fats because cells have no way of storing fats D.) they will not accumulate fats because carbohydrates have less energy per gram than fats

B.) they will accumulate fats because cells can convert glycolytic metabolites into lipids

What does the term "gluconeogenesis" refer to? A.) the transport of glucose across a cell membrane B.) the breakdown of glucose during fermentation C.) the synthesis of glucose from small organic molecules such as pyruvate D.) the release of glucose from molecules such as glycogen E.) the breakdown of glucose during glycolysis

C.) the synthesis of glucose from small organic molecules such as pyruvate