Cellular Respiration

Question 1

Where is chemical energy stored in molecules like glucose?

Answer 1

In the bonds

Question 2

What is cellular respiration in simple terms?

Answer 2

When mitochondria break down carbohydrates (and fats) to generate adenosine triphosphate (ATP) molecules

Question 3

What is ATP made up of?

Answer 3

Made up a 5 carbon sugar (ribose sugar), a nitrogen base (adenine) and 3 phosphate molecules

Question 4

Why is ATP a high energy molecule?

Answer 4

Due to the negative charges on the phosphate groups

Question 5

How does ATP release energy?

Answer 5

When the third phosphate group breaks, energy is released

Question 6

How does ATP release energy?

Answer 6

When the third phosphate group breaks, energy is released

Question 7

What is dephosphorylation?

Answer 7

The removal of a phosphate group from a molecule

Question 8

What is the Matrix?

Answer 8

Fluid-filled space of the inner membrane that contains enzymes for breaking down carbohydrates and other high energy molecules

Question 9

What is the Cristae?

Answer 9

Folds found within inner membrane that provide large surface area for ATP production

Question 10

What is the formula for cellular respiration?

Answer 10

C6H12O6(s) + 6O2(g) → 6 CO2(g) + 6 H2O (l) + energy (heat)

Question 11

What is oxidization?

Answer 11

When an atom or molecule loses an electron

Question 12

What is reduction?

Answer 12

When an atom or molecule gains an electron

Question 13

Whenever one molecule is _______, another must be _________

Answer 13

OXIDIZED, REDUCED

Question 14

In cellular respiration, glucose is _______, and oxygen is _________

Answer 14

OXIDIZED, REDUCED

Question 15

How does cellular respiration release energy?

Answer 15

By oxidizing molecules of glucose to carbon dioxide

Question 16

What type of reaction is the breakdown of glucose?

Answer 16

An oxidation-reduction reaction

Question 17

How many ATP molecules does the breakdown of one glucose form?

Answer 17

36 to 38 ATP molecules

Question 18

What is aerobic cellular respiration?

Answer 18

• A series of enzyme catalyzed reactions where electrons are transferred from glucose to oxygen, generating ATP
• Oxygen is required, therefore this process is performed by organisms that live in oxygen-rich environments

Question 19

What is anaerobic cellular respiration?

Answer 19

• Does not require oxygen to produce ATP
• Performed by organisms living in anoxic (oxygen deficient) environments

Question 20

What is fermentation?

Answer 20

Process does not require oxygen; can be carried out by aerobic organisms (ex. yeast, bacteria, muscle cells of mammals)

Question 21

What is glycolysis?

Answer 21

• An anaerobic process that is performed by all living cells
• Occurs in the cytosol
• Breaks down and splits glucose into two molecules of pyruvate which is then used in the process of cellular respiration to produce ATP
• Also produces NADH through several more reactions that result in the reduction of NAD+ (nicotinamide adenine dinucleotide)

Question 22

How much ATP is produced by glycolysis?

Answer 22

Glycolysis produces 4 ATP, but Initiating glycolysis uses 2 ATP, therefore there is a net value of 2.

Question 23

Where does glycolysis occur?

Answer 23

Occurs outside the mitochondria, in the cytoplasm (cytosol)

Question 24

What happens if there is NO oxygen available after glycolysis?

Answer 24

Fermentation will occur

Question 25

What is fermentation?

Answer 25

The further reduction of pyruvate via oxidation of NADH to NAD+

Question 26

Where does fermentation occur?

Answer 26

Occurs in the cytoplasm of cell

Question 27

What are the two common types of fermentation?

Answer 27

1. Lactate (animal cells) fermentation
2. Ethanol (in yeast) fermentation in eukaryotes

Question 28

When does lactate fermentation occur?

Answer 28

During times of strenuous exercise because the muscles require more ATP than aerobic respiration can provide

Question 29

What are the steps of lactate fermentation?

Answer 29

• The NADH generated during glycolysis transfers it’s H+ to pyruvate, changing pyruvate to lactic acid (lactate) and regenerating NAD+
• Liver is able to change lactic acid back to pyruvate allowing aerobic respiration to continue when exercise has ceased

Question 30

What are the steps of ethanol fermentation?

Answer 30

• Carbon dioxide molecule is removed from pyruvate, creating a 2 carbon molecule called acetaldehyde.
• NADH pass their e- and H+ to acetaldehyde creating NAD+ and ethanol (a waste product like carbon dioxide)
• This process supplies a small amount of energy (from glycolysis) and regenerates NAD+ (returning to glycolysis)

Question 31

What is pyruvate oxidization?

Answer 31

• Pyruvate enters mitochondria and loses a carbon atom in the process, forming CO2
• CO2 bonds with Coenzyme A (CoA) to form Acetyl CoA → NAD+ reduces to NADH

Question 32

What happens if there is oxygen available after glycolysis?

Answer 32

The process will move to the Krebs Cycle

Question 33

Where does the Krebs Cycle occur?

Answer 33

Occurs in matrix of mitochondria

Question 34

What is the Krebs Cycle?

Answer 34

• Processes Acetyl CoA through a series of reactions that extract electrons and hydrogen ions, producing NADH and FADH2
• Small amount of ATP is produced
• Electrons and hydrogen ions are carried to electron transport chain
• By the end of the Kreb’s Cycle, ALL 6 carbon atoms in the glucose have been oxidized and released as waste in the form of CO2
• Krebs cycle occurs twice per each molecule of glucose