Exam 2: Glycolysis vs. Citric Acid cycle vs. ETC

Question 1

Where does glycolysis take place in a cell?

Answer 1

Glycolysis takes place in the cytoplasm

Question 2

Where does the KREB/ citric acid cycle take place in a cell?

Answer 2

Within the mitochondrion, the citric acid cycle occurs in the mitochondrial matrix.

Question 3

Where does electron transport take place in a cell?

Answer 3

In the mitochondria (inner membrane)

(oxidative metabolism occurs at the internal folded mitochondrial membranes (cristae).)

Question 4

What are the reactants of glycolysis?

Answer 4

glucose (C6 H12 O6) (the splitting of glucose)

(Glycolysis is the first stage of cellular respiration, and the reactants are one molecule of glucose and two molecules of ATP (adenosine triphosphate). The ATP molecules provide energy so that the reaction can occur.)

Question 5

What are the reactants of KREB/ citric acid cycle?

Answer 5

2 pyruvate (pyruvate= 3 carbon molecule)

(The Krebs cycle is a closed-loop set of reactions in eight steps: The two-carbon acetyl CoA is combined with a four-carbon oxaloacetic acid and hydrolyzed to produce a six-carbon compound called citric acid or citrate.)

Question 6

What are the reactants of the electron transport chain?

Answer 6

NADH/FADH2

(The reactants of the electron transport chain are NADH, FADH2, protons, ADP, and oxygen. NADH and FADH2 are electron carriers produced during glycolysis and the Citric Acid Cycle that donate electrons to the protein complexes in the inner membrane of the mitochondria.)

Question 7

What are the major products of glycolysis?

Answer 7

2 pyruvate (pyruvate= 3 carbon molecule)

(Glycolysis produces 2 ATP, 2 NADH, and 2 pyruvate molecules: Glycolysis, or the aerobic catabolic breakdown of glucose, produces energy in the form of ATP, NADH, and pyruvate, which itself enters the citric acid cycle to produce more energy.)

Question 8

What are the major products of the KREB/ citric acid cycle?

Answer 8

NADH/FADH2 (High-energy electron carriers)

(the Krebs or citric acid cycle, which is a series of reactions that takes in acetyl CoA and produces carbon dioxide, NADH, FADH2, and ATP or GTP.)

Question 9

What are the major products of the electron transport chain?

Answer 9

ATP

(The end products of the electron transport chain are water and ATP.)

Question 10

What is the byproduct of glycolysis?

Answer 10

There are technically no “waste products” of glycolysis, however:

The byproducts of glycolysis are ATP and NADH, which are used as energy sources by the body. Glycolysis is the process of breaking down glucose into pyruvate, and the final output is two molecules of pyruvate, ATP, NADH, and water

Question 11

What is the main byproduct of the KREB/ citric acid cycle?

Answer 11

CO2

(The main byproduct of the Krebs cycle is carbon dioxide, which is a gas that animals exhale. The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions that take place in the mitochondria and produce energy for cells. The cycle involves redox, dehydration, hydration, and decarboxylation reactions that produce ATP (adenosine triphosphate), a coenzyme energy carrier for cells.)

Question 12

What is the main byproduct of the electron transport chain?

Answer 12

H2O

(ATP and water are products of the electron transport chain. The electron transport chain takes place in the cytoplasm of the cell. The largest byproduct of the electron transport chain is carbon dioxide.)

Question 13

How much ATP is produced at the end of glycolysis?

Answer 13

2 ATP

(Glycolysis produces four ATP molecules at the end of the process, resulting in a net gain of two ATP molecules. Glycolysis is the first stage of cellular respiration, and it occurs in the cytosol of the cytoplasm. During glycolysis, enzymes split a glucose molecule into two pyruvate molecules, releasing energy in the process. The first half of the pathway uses two ATP molecules to prepare the six-carbon ring for cleavage, and the second half produces four ATP molecules. Glycolysis also produces two NADH molecules, with each NADH giving three ATP molecules.)

Question 14

How much ATP is produced at the end of the KREB/ citric acid cycle?

Answer 14

2 ATP

Question 15

How much ATP is produced at the end of the electron transport chain?

Answer 15

32 ATP

(The electron transport cycle generates around 30–32 ATP molecules, according to a recent study.)

Question 16

What does oxygen do in the electron transport chain?

Answer 16

Oxygen is an electron carrier that accepts two protons from the intermembrane space of mitochondria to produce water in the matrix of the mitochondria

Question 17

What does ATP synthesis do in the electron transport chain?

Answer 17

ATP synthase takes 3 protons from the intermembrane space of mitochondria into the matrix. The enzyme will then also convert ADP and Pi to produce ATP in the mitochondria matrix. (oxidation phosphorylation)

Question 18

How much ATP is required to initiate glycolysis?

Answer 18

2 ATP

(Energy is needed at the start of glycolysis to split the glucose molecule into two pyruvate molecules. These two molecules go on to stage II of cellular respiration. The energy to split glucose is provided by two molecules of ATP)

Question 19

How much pyruvate is produced during glycolysis?

Answer 19

2 pyruvate (pyruvate= 3 carbon molecule)

(Through the process of glycolysis, one molecule of glucose breaks down to form two molecules of pyruvate.)

Question 20

What is the 3-carbon molecule produced by glucose?

Answer 20

pyruvate

(The process begins with Glycolysis. In this first step, a molecule of glucose, which has six carbon atoms, is split into two three-carbon molecules. The three-carbon molecule is called pyruvate.)

Question 21

How much carbon makes up a glucose molecule?

Answer 21

6 carbon

(The process begins with Glycolysis. In this first step, a molecule of glucose, which has six carbon atoms, is split into two three-carbon molecules. The three-carbon molecule is called pyruvate.)

Question 22

How many ATP molecules are involved in all of glycolysis?

Answer 22

4 ATP
(2 ATP used in the first phase of glycolysis, 2 ATP net gain)

Question 23

How much NADH is produced during glycolysis?

Answer 23

2 NADH
(During glycolysis, one glucose molecule is split into two pyruvate molecules, using 2 ATP while producing 4 ATP and 2 NADH molecules.)

Question 24

What initiates the KREB cycle?

Answer 24

pyruvate from glycolysis (3 carbon molecule), which becomes acetyl coA (2 carbon molecule), that will bind to 4 carbon molecule to become oxaloacetate (OAA), creating a 6 carbon molecule known as citric acid

Question 25

What is citric acid converted to?

Answer 25

FADH2 and NADH

Question 26

How much ATP does FADH2 yield?

Answer 26

1.5 ATP

Question 27

How much ATP does NADH yield?

Answer 27

2.5 ATP

Question 28

How much NADH is produced by one cycle of the KREB/ citric acid cycle?

Answer 28

3 NADH

(The Krebs cycle summarizes a circular series of reactions in the mitochondria to metabolize AcCoA to two molecules of CO2 with resultant generation of one molecule of GTP, three molecules of NADH, and one molecule of FADH2. GTP is equivalent to ATP in terms of energy charge.)

Question 29

How much FADH2 is produced by one cycle of the KREB/ citric acid cycle?

Answer 29

1 FADH2

(Since each glucose molecule is broken down into 2 pyruvate molecules, and each pyruvate molecule goes through the Krebs cycle, a total of 2 FADH2 molecules are produced per glucose molecule.)

Question 30

How much GTP is produced by one cycle of the KREB/ citric acid cycle?

Answer 30

1 GTP

(The GTP can be used to produce ATP, which is equivalent to energy charge in terms of GTP.)

Question 31

What does NADH become once it donates electrons to the electron transport chain?

Answer 31

NAD+

(Electrons from NADH enter the electron transport chain in complex I, which consists of nearly 40 polypeptide chains. These electrons are initially transferred from NADH to flavin mononucleotide and then, through an iron-sulfur carrier, to coenzyme Q—an energy-yielding process with ΔG°´ = -16.6 kcal/mol.)

Question 32

What does FADH2 become once it donates electrons to the electron transport chain?

Answer 32

FAD
FADH2 in the matrix deposits electrons at Complex II, turning into FAD and releasing 2 H+.

(When FADH2 donates electrons to the electron transport chain (ETC), it becomes FAD, or quinone form. FADH2 is the reduced form of FADH, and FAD accepts two electrons and two protons to become FADH2. FADH2 then transports electrons to complex II in the ETC.)

Question 33

What is the electron acceptor of the electron transport chain?

Answer 33

Oxygen

(oxygen is the final electron acceptor in the electron transport chain, which allows for oxidative phosphorylation. Without oxygen, the electrons will be backed up, eventually causing the electron transport chain to halt.)

Question 34

Explain the steps of the electron transport chain.

Answer 34

1) The oxidative phosphorylation process, also known as the electron transport chain, is a collection of four protein complexes that combine redox events to produce an electrochemical gradient that results in the production of ATP.

2) Both photosynthesis and cellular respiration take place in mitochondria.

3) By transferring electrons from NADH and FADH2 through a series of complexes and electron carriers, these carriers ultimately produce ATP.

4) The electron transport cycle generates around 30–32 ATP molecules, according to a recent study.

5) This NADH consequently produces one to two ATP.

6) The highest yield of ATP produced per glucose in eukaryotic cells is potentially between 36 and 38 depending on how the two NADH made in the cytoplasm during glycolysis reach the mitochondria and if the resulting yield is 2 or 3 ATP per NADH.

7) The oxidative phosphorylation process, which produces ATP as a result of an electrochemical gradient created by the electron transport chain, is a collection of four protein complexes that link redox processes.

8) Both photosynthesis and cellular respiration take place in mitochondria.

Question 35

How many ATP molecules are produced in anaerobic respiration?

Answer 35

2 ATP

(in anaerobic respiration, one glucose molecule produces two ATP molecules through glycolysis.)

Question 36

How many ATP molecules are produced in aerobic respiration?

Answer 36

38 ATP

(with oxygen, organisms can break down glucose all the way to carbon dioxide. This releases enough energy to produce up to 38 ATP molecules. Thus, aerobic respiration releases much more energy than anaerobic respiration.)

Question 37

How many ATP molecules are produced in the citric acid cycle?

Answer 37

2 ATP

(Since two acetyl CoA molecules are generated from the two pyruvic acid molecules produced in glycolysis, the total number of these molecules yielded in the citric acid cycle is doubled to 2 ATP, 6 NADH, 2 FADH2, 4 CO2, and 6 H+.)

Question 38

What is the significance of cyanide in the electron transport chain?

Answer 38

electrons are blocked by cyanide from being accepted by oxygen, causing the cell to die.

(Cyanide poisons the mitochondrial electron transport chain within cells and renders the body unable to derive energy (adenosine triphosphate—ATP) from oxygen. 4 Specifically, it binds to the a3 portion (complex IV) of cytochrome oxidase and prevents cells from using oxygen, causing rapid death.)

Question 39

Which chemical equation for cellular respiration?

a) C6H12O6 + 6O2 —> 6CO2 + 6H2O

b) 6CO2 + 6H2O —> C6H12O6 + 6O2

Answer 39

a) C6H12O6 + 6O2 —> 6CO2 + 6H2O

(This equation states that glucose (C6H12O6) and oxygen (O2) are used to produce carbon dioxide (CO2), water (H2O), and energy in the form of ATP.)

Question 40

Which chemical equation is for photosynthesis?

a) C6H12O6 + 6O2 —> 6CO2 + 6H2O

b) 6CO2 + 6H2O —> C6H12O6 + 6O2

Answer 40

b) 6CO2 + 6H2O —> C6H12O6 + 6O2

(This equation means that six carbon dioxide molecules and six water molecules are converted into a sugar molecule and six oxygen molecules by light energy captured by chlorophyll.)