Deck 8: Harvesting Energy: Glycolysis and Cellular Respiration

Question 1

The complete breakdown of glucose in the presence of oxygen occurs in two major stages:________ and ______________. The first of these stages occurs in the_____________ of the cell, and the second stage occurs in organelles called____________. Conditions in which oxygen is present are described as ___________.

Answer 1

Glucose metabolism consists of three major pathways - Glycolysis, Fermentation, and cellular respiration.
Among the three pathways, glycolysis and fermentation occur in cytoplasm of the cell, which is also called as cytosol, while cellular respiration occurs in mitochondria. Figure 1: Locations of glucose metaboilsm
As the cellular respiration requires oxygen, it is called aerobic process.
So, answer for the first blank is glycolysis , second blank is cellular respiration , third blank is cytosol , fourth blank is mitochondria , and fifth blank is aerobic.

Question 2

Which of the following is produced in the intermembrane space of mitochondria?

A) ATP
B) a high concentration of H +
C) NADH and FADH 2
D) acetyl CoA

Answer 2

ATP (adenosine triphosphate) molecules are produced during the breakdown of glucose through various processes like glycolysis, fermentation, and cellular respiration. Glycolysis and fermentation occurs in cytoplasm of cell, whereas the cellular respiration occurs in the mitochondrial matrix.
NADH (Nicotinamide Adenine Dinucleotide hydrogen) and FADH 2 (Flavin Adenine Dinucleotide di-hydrogen) are the molecules produced in mitochondrial matrix, through cellular respiration or Kreb's cycle.
Acetyl Coenzyme-A (Acetyl CoA) is the molecule that triggers the Kreb's cycle. This is produced in the cytosol and enters the mitochondria through the mitochondrial membrane.
So, options (a), (c), and (d) are in correct.
Electron transport chain is the system of a series of redox reaction that occur within the membrane of the mitochondria. Acetyl CoA gets transported into the mitochondrial matrix through this system.
A high concentration gradient of hydrogen ions (H + ) is created in the inter-membrane space of mitochondria that not only facilitates the transport of the Acetyl CoA but also helps the generation of ATP molecules throughout the transportation process.
Therefore, option (b) is correct.

Question 3

Which of the following is True for one glucose molecule?

A) Fermentation produces 2 ATP.
B) Glycolysis followed by fermentation nets 4 ATP.
C) Ethanol is one end product of glycolysis.
D) The overall equation for photosynthesis is the reverse of that for aerobic glucose breakdown.

Answer 3

Glucose metabolism refers to a series of biological processes that breaks down glucose molecules to yield ATPs.
Overall, the glycolysis and fermentation pathways run twice to produce four ATP molecules out of one glucose molecule and bi-products such as Ethanol and Carbon dioxide (CO 2 ).
Glycolysis, a part of the glucose metabolism, produces four ATPs among which, two are re-utilized, yielding a net gain of two ATP molecules.
So, options (a), (b), and (c) are incorrect, as the statements are false.
Overall reactions of photosynthesis and anaerobic glucose breakdown are as follows:
Photosynthesis:
6CO 2 + 6H 2 O ? C 6 H 12 O 6 + 6O 2
Glucose breakdown:
C 6 H 12 O 6 + 6O 2 ? 6CO 2 + 6H 2 O
Observing the above reactions, it is clear that the overall reaction of photosynthesis is exactly the opposite to that of the anaerobic glucose breakdown.
Hence, option (d) is correct.

Question 4

What molecule is the end product of glycolysis? How are the carbons of this molecule used in stage 1 of cellular respiration? In what form is most of the energy from the Krebs cycle captured?

Question 5

Starting with glucose (C 6 H 12 O 6 ), write the overall equation for glucose breakdown in the presence of oxygen, compare this to the overall equation for photosynthesis, and explain how the energy components of the equations differ.

Question 6

Describe the electron transport chain and the process of chemiosmosis.

Question 7

Many microorganisms in lakes use cellular respiration to generate energy. Dumping large amounts of raw sewage into rivers or lakes typically leads to massive fish kills, even if the sewage itself is not toxic to fish. What kills the fish? How might you reduce fish mortality after raw sewage is accidentally released into a small pond?

Question 8

Why is oxygen necessary for cellular respiration to occur?

Question 9

Conditions in which oxygen is absent are described as ___________. Some microorganisms break down glucose in the absence of oxygen using___________ , which generates only _________molecules of ATP. This process is followed by__________ , in which no more ATP is produced, but the electron-carrier molecule__________ is regenerated so it can be used in further glucose breakdown.

Question 10

Compare the structure of chloroplasts (described in Chapter 7) to that of mitochondria, and describe how the similarities in structure relate to similarities in function.

Question 11

The portion of glucose breakdown that produces the most ATP is

A) chemiosmosis.
B) glycolysis.
C) the Krebs cycle.
D) fermentation.

Question 12

Draw and label a mitochondrion, and explain how its structure relates to its function.

Question 13

Imagine a hypothetical situation in which a starving cell reaches the stage where every bit of its ATP has been depleted and converted to ADP plus phosphate. If at this point you place the cell in a solution containing glucose, will it recover and survive? Explain your answer based on what you know about glucose breakdown.

Question 14

Yeasts in bread dough and alcoholic beverages use a type of fermentation that generates ______________ and ______________. Muscles pushed to their limit use ______________ fermentation. Which form of fermentation is used by microorganisms that produce yogurt, sour cream, and sauerkraut? ______________

Question 15

ATP synthase enzymes are located in the

A) cytosol.
B) inner mitochondrial membrane.
C) intermembrane space.
D) mitochondrial matrix.

Question 16

What role do the following play in breaking down and harvesting energy from glucose: glycolysis, cellular respiration, chemiosmosis, fermentation, and the electron carriers NAD + and FAD?

Question 17

Some species of bacteria that live at the surface of sediment on the bottom of lakes are capable of using either glycolysis plus fermentation or cellular respiration to generate ATP. There is very little circulation of water in lakes during the summer. Predict and explain what will happen to the bottommost water of lakes as the summer progresses, and describe how this situation will affect energy production by bacteria.

Question 18

During cellular respiration, the electron transport chain pumps H + out of the mitochondrial ______________ into the ______________, producing a large ______________ of H +. The ATP produced by cellular respiration is generated by a process called ______________. ATP is generated as H + travels through membrane channels linked to ______________.

Question 19

Fermentation

A) regenerates NADH.
B) follows cellular respiration when oxygen is lacking.
C) generates additional ATP after glycolysis.
D) uses pyruvate as its substrate.

Question 20

Outline the two major stages of glycolysis. How many ATP molecules (overall) are generated per glucose molecule during glycolysis? Where in the cell does glycolysis occur?

Question 21

Some species of bacteria use aerobic respiration, and other species use fermentation. In an oxygen-rich environment, would either type be at a competitive advantage? What about in an oxygen-poor environment?

Question 22

The cyclic portion of cellular respiration is called the ______________ cycle. The molecule that enters this cycle is ______________. How many ATP molecules are generated by the cycle per molecule of glucose? ______________ What two types of high-energy electroncarrier molecules are generated during the cycle? ______________ and ______________