Cell Biology Chapter 13 SmartWorks

Which of the following processes generates the largest number of ATP molecules?

oxidative phosphorylation

What are the end products of glycolysis?

- ATP - NADH - pyruvate - Each molecule of glucose that enters the pathway produces two molecules of pyruvate, two ATPs, and two NADHs

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.

- The reaction is an irreversible reaction - The reaction generates the product fructose 1,6-bisphosphate - The enzyme that catalyzes step 3 is phosphofructokinase - The enzyme uses an ATP.

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.

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

How many FADH2 molecules are made from the complete oxidation (fatty acid oxidation + Krebs cycle) of palmitic acid? (16 C)

15

How many FADH2 molecules are produced from the complete oxidation of one molecule of glucose?

2

When fatty acids are oxidized to produce acetyl CoA, each cycle of the reaction removes how many carbon atoms from the fatty acid molecule?

2

From one glucose molecule, how much net energy (in the form of ATP and NADH) is produced during glycolysis?

2 ATP, 2 NADH

How many molecules of NADH are produced from the complete oxidation (fatty acid oxidation + Krebs cycle) of one molecule of palmitic acid?

31 - 7 from FAO - 24 from Krebs

Most of the energy released by oxidizing glucose is saved in the high-energy bonds of what molecules?

ATP and other activated carriers

Which of the following are required for glycolysis to take place?

ATP, ADP, Pi, NAD+

Identify the molecule

Acetyl CoA

How do fermentation and anaerobic respiration differ?

Anaerobic respiration involves an electron transport chain, while fermentation does not

Which of the following describes a breakdown process in which enzymes degrade complex molecules into simpler ones?

Catabolism - Catabolic reactions include glycolysis, which breaks down glucose into pyruvate, and the citric acid cycle, which completes the oxidation of the carbons in pyruvate

The citric acid cycle converts the carbon atoms in acetyl CoA to which of the following?

CO2

Identify the molecule

FAD

Experiments performed by Hans Krebs in the 1930s revealed that the set of reactions that oxidize food molecules and produce CO2 occur in a cycle. In one experiment, Krebs exposed pigeon muscles to malonate, a compound that inhibits succinate dehydrogenase—the enzyme that converts succinate to fumarate, indicated by the "X" in the linear representation of the reactions of the citric acid cycle (below). citrate --> --> --> --> succinate -X-> fumarate --> --> oxaloacetate Which of the following observations, made in malonate-treated muscle, led Krebs to believe that this set of reactions is cyclical?

If fumarate were added, succinate would accumulate

You have joined a lab that studies the metabolic pathway shown below. Just recently, an inhibitor for one of the enzymes, enzyme 3, has become available and the head of the lab wants you to use this inhibitor to determine whether the pathway is linear (as shown) or circular, with another enzyme (not shown) converting F back to A. You have access to all the molecules. What result suggests that the pathway may be circular rather than linear? Path: A to F (enzyme 1-5 between each step)

Inhibition of enzyme 3 and addition of extra metabolite D leads to buildup of C

What is true of the enzyme glycogen phosphorylase, which breaks down glycogen?

It is inhibited by glucose 6-phosphate and by ATP

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?

NAD+

Identify the molecule. Be specific

NADH

In the absence of oxygen, in cells that cannot carry out fermentation, glycolysis would halt at which step?

the oxidation of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate

Which of the following is true for eukaryotic cells?

Sugars and fats are both converted to acetyl CoA in the mitochondria

What does it mean for a bond to be "high energy," such as the bonds between phosphate groups in ATP?

The hydrolysis of the bond is energetically favorable

Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell?

mitochondrion

Under anaerobic conditions, which metabolic pathway regenerates the supply of NAD+ needed for glycolysis?

fermentation

When food is plentiful, animals can store glucose as what?

glycogen

Useful energy is obtained by cells when sugars derived from food are broken down by which processes?

glycolysis, the citric acid cycle, and oxidative phosphorylation

In step 6 of glycolysis, glyceraldehyde 3-phosphate, which has one phosphate group, is converted into 1,3-bisphosphoglycerate, which has two. Where does the extra phosphate group come from?

inorganic phosphate

In cells that cannot carry out fermentation, which products derived from glycolysis will accumulate under anaerobic conditions?

pyruvate and NADH

When nutrients are plentiful, plants can store glucose as what?

starch

If cells that cannot carry out fermentation were grown in anaerobic conditions, at which step would glycolysis halt?

step 6: where NAD+ is converted to NADH

The synthesis of ATP in glycolysis occurs by which process?

substrate-level phosphorylation

In what form do plant and animal cells store fat?

triacylglycerol

How many ATP molecules must be invested during the first part of glycolysis for each molecule of glucose broken down?

two