Chapter 6 - Cellular Respiration

Question 1

Respiration

Answer 1

Gas exchange that occurs in the lungs

(aka breathing)

Question 2

Cellular respiration

Answer 2

The aerobic process used by cells in order to harvest energy from food molecules.

(Breathing supplies the oxygen needed for cellular respiration or occur. Then carried away the CO2 waste.)

Question 3

Redox reactions

Answer 3

Chemical reactions involve the transfer of electrons

OILRIG
OIL= oxidation is loss (of e-)
RIG = reduction is gain (of e-)

Question 4

NAD+

Answer 4

(Nicotinamide adenine dinucleotide)

Accepts electrons in cellular respiration.

A coenzyme that cells make from the vitamin niacin. It is used to shuttle electrons in redox reactions, becoming reduced to NADH plus H+

Question 5

Glycolysis

Answer 5

Occurs in the cytoplasm

Starts with 4 ATP, but used 2 to begin
- 1 glucose molecule (6C), breaks down into 2 pyruvate molecules (3C each)

• during the process, glucose has lost 4 hydrogen ions that now bind with 2 molecules of NAD+, which reduces it to 2 NADH and 2H+ (which goes straight to the Electron Transport Chain).
• this process ends with a net gain of 2 ATP = 4 ATP total

Question 6

Pyruvate to Acetyl CoA

Answer 6

Occurs in mitochondrial matrix.

• the 2 pyruvate molecules are oxidized into 2 acetyl CoA, and are brought into citric acid cycle.
• when entering the mitochondria, each pyruvate reduces and loses a CO2 molecule (which leaves as waste), and a pair of H ions. The H’s bind to NAD+ and reduce it to 2NADH+ and 2H+ (these go straight to the ETC.)

Question 7

Citric acid cycle

Answer 7

Occurs in the mitochondrial matrix.

• is a cycle that must repeat twice per glucose since it is processing 2 acetyl CoA’s.
• the acetyl CoA’s are oxidized and 4CO2 (2 per acetyl CoA) are released as waste.
• 6 NAD+ get reduced to 6NADH+ and H+ 3 per acetyl CoA). 2 FAD is reduced to FADH2 (1 per acetyl CoA)
• and 2 ATP are generated (1 per acetyl CoA)

All these products get brought to the electron transport chain.

Question 8

Electron transport chain
(oxidative phosphorylation)

Answer 8

Occurs in the cristae.

• all the NADH’s and FADH will donate their H ions and 24 total electrons.
• the electrons and H ions move through proton pumps and electronspropel H ions out of the pump and into the inner membrane space.
  -these H ions will make a [ ] gradient and diffuse back into the matrix via the enzyme ATP synthase. This makes the ATP synthase spin and turn ADP into ATP. (Chemiosmosis)
• and the end of the ETC, the loose electrons will bind to a oxygen molecule and H ions to form water.

Total ATP per glucose = 30-32
(But approx. 10 mil ATP made per second)

Question 9

Chemiosmosis

Answer 9

An energy coupling mechanism that uses the energy of hydrogen ion gradients in membranes to drive cellular work, such as the phosphorylation of ADP to ATP

Question 10

How do prokaryotes gain energy

Answer 10

Through the anaerobic process of glycolysis, which gives them 2 ATP per glucose.

Question 11

How does NADH+ H+ get reduced if there is no oxygen?

Answer 11

Fermentation

The NADH+ H+ will become oxidized into NAD+ again when it reduces other organic molecules within the cell
Ex. Alcohol or lactic acid

Question 12

How do cells capture the energy released by cellular respiration

Answer 12

They produce ATP

Question 13

How much of daily calories do humans use to maintain brain cells and power other life-sustaining activities?

Answer 13

75%

Question 14

Which phase of cellular respiration does substrate level phosphorylation take place?

Answer 14

Glycolysis and the citric acid cycle

Question 15

What happens to NADH in fermentation

Answer 15

The NADH is oxidized to form NAD+

(Loses electrons)