Biology Chapter 4

Question 1

Cellular respiration makes ATP by ________ _____ _______

Answer 1

breaking down sugars

Question 2

A process that releases chemical energy from sugars and other carbon-based molecules to make ATP when oxygen is present

Answer 2

Cellular respiration

Question 3

Cellular respiration is a(n) ________ process

Answer 3

aerobic

Question 4

Requires oxygen to take place

Answer 4

aerobic

Question 5

Before mitochondria can make ATP from food, foods are broken down into smaller molecules, such as glucose, which store energy. Then, ……

Answer 5

Glucose is broken down

Question 6

Splits glucose into two 3-carbon molecules and makes two molecules of ATP

Answer 6

Glycolysis

Question 7

What are the products of glycolysis?

Answer 7

2 pyruvate molecules
2 molecules of NADH (go to the Krebs Cycle)
4 molecules of ATP (net gain of 2 ATP)

Question 8

Where does glycolysis take place?

Answer 8

In a cell’s cytoplasm

Question 9

Photosynthesis and Cellular Respiration are kind of opposites because:

Answer 9

Photosynthesis absorbs energy to build sugars
Mitochondria release chemical energy stored in sugars to make ATP

Question 10

What are the reactants of Cellular Respiration?

Answer 10

Sugars (C6H12O6)
Oxygen (O2)

Question 11

What are the products of Cellular Respiration?

Answer 11

Carbon Dioxide (CO2) - waste product
Water (H2O) - waste product

Question 12

Up to how many ATP are produced from one molecule of glucose?

Answer 12

From 36-38:
2 from glycolysis
34 or 36 from cellular respiration

Question 13

Summarize the process of glycolysis

Answer 13

1. 2 ATP molecules energize a 6-carbon glucose molecule. (2 ATP -> 2 ADP). The glucose molecule is split into 2 3-carbon molecules. A series of enzymes and chemical reaction rearranges the 3-carbon molecules.
2. Energized electrons from the 3-carbon molecules are transferred to NAD+ to make NADH. A series of reactions converts the 3-carbon molecules to make 2 pyruvate. The 4 ADP from step one gain energy to make 4 ATP.

Question 14

What is NADH?

Answer 14

An electron carrier, utilized in Cellular Respiration

Question 15

What is the net ATP gain from glycolysis?

Answer 15

2 ATP

Question 16

What are the products of glycolysis?

Answer 16

2 net ATP, 2 Pyruvate, 2 NADH
*the pyruvate and NADH move on to the Krebs cycle. 2 of the 4 ATP produced cycle back to restart glycolysis.

Question 17

Where does the Krebs Cycle take place?

Answer 17

Mitochondrion matrix

Question 18

What is the main function of the Krebs Cycle?

Answer 18

To transfer high-energy electrons to molecules that carry them to the electron transport chain.

Question 19

What is FADH2?

Answer 19

A molecule, like NADH, that is an electron carrier.

Question 20

Summarize the Krebs Cycle

Answer 20

1. One Pyruvate molecule from glycolysis is broken down into a 2 carbon molecule. One carbon dioxide molecule is given off as a waste product.
2. Coenzyme A bonds to the 2-carbon molecule broken down from pyruvate.
3. The 2- carbon part of the CoA 2-carbon molecule is added to a 4-carbon molecule, forming a 6-carbon molecule of citric acid.
4. Citric acid is broken down into a 5-carbon molecule. One CO2 molecule is released, and energy transforms a molecule of NAD+ to NADH, which goes to the ETC.
5. The 5-carbon molecule is broken down by an enzyme, forming a 4-carbon molecule. A molecule of NAD+ transforms to NADH (goes to ELC), and a molecule of ADP transforms to ATP. One carbon dioxide molecule is released.
6. The 4-carbon molecule is rearranged by enzymes. High-energy electrons are released, forming molecules of NADH and FADH2, which leave the Krebs Cycle and go to the ELC. The 4-carbon molecule remains, and is used again in step 3 to form citric acid.

Question 21

Which molecule is formed when Coenzyme A bonds to the 2-carbon molecule broken down form pyruvate?

Answer 21

An intermediate molecule of 2-carbon CoA

Question 22

How is citric acid formed?

Answer 22

The 2-carbon part of the intermediate 2-carbon CoA molecule bonds to a 4 carbon molecule, making a citric acid molecule. Coenzyme A is recycled back to step 2.

Question 23

What are the products of the Krebs Cycle from ONE of the molecules of pyruvate from glycolysis?

Answer 23

3 molecules of carbon dioxide given off as a waste product
1 molecule of ATP
4 molecules of NADH to the ELC
1 molecule of FADH2 to the ELC

Question 24

How many total ATP are produced from the Krebs cycle from one molecule of glucose (indirectly)?

Answer 24

2 molecules of ATP; 1 from each pyruvate molecule

Question 25

Where does the Electron Transport Chain take place?

Answer 25

In the Inner mitochondrial membrane

Question 26

What are the reactants of the Electron Transport Chain?

Answer 26

Molecules of NADH and FADH2 which supply electrons that are transported across the proteins in the inner membrane.

Question 27

How are proteins in the mitochondrial membrane used in the Electron Transport Chain?

Answer 27

The proteins use energy from the electrons supplied by NADH and FADH2 to pump hydrogen ions against a concentration gradient, and across the inner mitochondrial membrane.

Question 28

Summarize the steps of the Electron Transport Chain

Answer 28

1. Electrons are removed from the molecules of NADH and FADH2 coming from the Krebs Cycle. The electrons are transported across the proteins in the inner mitochondrial membrane. 2. The proteins use the energy from the electrons (from the molecules of NADH and FADH2) to transport hydrogen ions across the membrane. These hydrogen ions build up on the inside of the inner mitochondrial membrane. 3. Hydrogen ions diffuse through a protein channel in the inner membrane of the mitochondrion which contains ATP synthase. ATP synthase adds phosphate groups to ADP to produce ATP. 4. Oxygen picks up electrons and hydrogen ions that have already passed through the Electron Transport Chain to form Water molecules. The water molecules are given off as a waste product.

Question 29

At what rate does the Electron transport chain produce ATP?

Answer 29

For each pair of electrons that passes through the electron transport chain, an average of 3 ATP molecules are made.

Question 30

What are the products of the Electron Transport Chain?

Answer 30

Water- given off as a waste product Up to 34 molecules of ATP

Question 31

The production of ATP without oxygen continues through the anaerobic processes of glycolysis and _________

Answer 31

Fermentation

Question 32

Fermentation does/does not make ATP

Answer 32

Fermentation does NOT make ATP, but allows glycolysis to continue

Question 33

Which molecule used in fermentation picks up electrons?

Answer 33

NAD+; NAD+ picks up high-energy electrons form the splitting of glucose, and is necessary for glycolysis to continue (and make pyruvate and NADH which are used in both CR and Fermentation)

Question 34

What builds up in your cells in the absence of oxygen, and causes a burning feeling in your muscles?

Answer 34

Lactic Acid

Question 35

Summarize the process of Lactic Acid Fermentation

Answer 35

1. Pyruvate and NADH from glycolysis enter the fermentation process. 2 NADH molecules provide energy to convert pyruvate into lactic acid. As the NADH is used, it is converted back into NAD+. 2. 2 molecules of NAD+ are recycled back to glycolysis. This recycling of NAD+ allows glycolysis to continue.

Question 36

Why is the fermentation process not sustainable for the cells in your body?

Answer 36

Fermentation does not produce ATP, and glycolysis produces very little amounts of ATP. If your cells continue without oxygen, they will run out of energy to continue their normal processes.

Question 37

What are the products of Lactic Acid Fermentation?

Answer 37

2 lactic acid molecules

Question 38

What happens in your cells when oxygen is available again?

Answer 38

Your cells return to cellular respiration. The lactic acid is quickly broken down and removed from your cells.

Question 39

What does alcoholic fermentation occur in?

Answer 39

Yeasts, plants, etc... to make cheese, yogurt, and breads

Question 40

Summarize the steps of alcoholic fermentation

Answer 40

1. Pyruvate and NADH from glycolysis enter alcoholic fermentation. 2 NADH molecules provide energy to break down pyruvate into an alcohol and carbon dioxide. As the NADH molecules are used, they are converted back into molecules of NAD+. 2. The molecules of NAD+ are recycled back to glycolysis. The recycling of NAD+ allows glycolysis to continue.

Question 41

What are the products of alcoholic fermentation?

Answer 41

2 alcohol 2 carbon dioxide (released as a waste product)

Question 42

Describe how yeast in relation to glycolysis and fermentation allows dough to rise

Answer 42

The yeast breaks down sugars in the dough through glycolysis and alcohol fermentation. The carbon dioxide gas released as a waste product from alcoholic fermentation causes the dough to puff up and rise. When the dough is baked, the alcohol that is produced during fermentation evaporates into the air. The yeast in dough is killed by the heat of baking.