Ch. 9 Cellular Respiration

Question 1

what is fermentation?

Answer 1

fermentation is the step cellular respiration takes if there is no oxygen, and forms ethanol [in bacteria/yeast] or lactic acid [humans]

Question 2

what is aerobic respiration?

Answer 2

the process cellular respiration goes through when oxygen is present

Question 3

what is the summary equation for cellular respiration?

Answer 3

C6H12O6 + 6O2 +ADP +Pi -> 6CO2 + 6H2O + ATP + heat

Question 4

what is oxidation?

Answer 4

when a molecule in a rxn loses electrons or hydrogen = losing energy
often involves a gaining of O atoms

Question 5

what is reduction?

Answer 5

when a molecule in a rxn gains electrons or hydrogen = gains energy

Question 6

what is a reducing agent?

Answer 6

a molecule that causes the reduction of another molecule, getting oxidized itself

Question 7

what is an oxidizing agent?

Answer 7

a molecule causing the oxidation of another molecule, getting reduced itself

Question 8

what role do the coenzymes NAD+ and FAD+ play in cellular respiration?

Answer 8

the energy in electrons gets transferred from glucose to coenzymes, so NADH and FADH serve to carry the energy possessed by electrons [“high energy electron carriers”]

Question 9

what are the coenzymes used in cellular respiration? what are they derived from?

Answer 9

NAD/NADH+ - derived from niacin
FAD/FADH2 - from riboflavin
TPP - from thiamine
Acetyl CoA - from pantothenate

Question 10

what is the job of glycolysis?

Answer 10

to break down one glucose molecule into two pyruvate molecules for use in krebs cycle

Question 11

what are the substrates of glycolysis?

Answer 11

-2 NAD+
-2 ADP + Pi
-1 glucose

Question 12

what are the products of glycolysis?

Answer 12

-2 pyruvate
-2 ATP
-2 NADH

Question 13

where does glycolysis occur?

Answer 13

in the cytosol of the cell

Question 14

what is the prep step before the krebs cycle can begin?

Answer 14

-the 2 molecules of pyruvate created must be converted into 2x Acetyl CoA

Question 15

where does the pyruvate “prep step” occur?

Answer 15

within the mitochondrion matrix

Question 16

what are the substrates for the citric acid cycle? [4 of them]

Answer 16

-2x Acetyl CoA
-2x FAD
-6x NAD+
-2x ADP + Pi

Question 17

what are the products of the citric acid cycle?

Answer 17

-4x CO2
-6x NADH
-2x FADH
-2x ATP

Question 18

where does the krebs cycle occur?

Answer 18

within the matrix of the mitochondrion

Question 19

what is the function of NADH and FADH in the electron transport chain?

Answer 19

to give their high energy electrons to proteins in the ETC to power the proton pump [creates gradient]

Question 20

why is a proton gradient created in the electron transport chain?

Answer 20

-the gradient is established so H+ protons can flow back down the gradient through ATP synthase, which generates ATP from their kinetic energy

Question 21

what is chemiosmosis?

Answer 21

an “energy coupling mechanism” that uses chemical gradient energy to do work
ex- ATP synthase

Question 22

what happens to the high energy electrons once they have reached the end of the transport chain?

Answer 22

they are collected by a single O2 molecule (1/2O2), which picks up 2 H+ to balance the charges = creates water

Question 23

where does the electron transport chain take place?

Answer 23

-within the matrix and intermembrane space of the mitochondria

Question 24

what is the NET total of ATP generated from glycolysis, the krebs cycle, and electron transport chain?

Answer 24

-32 net ATP
-2 from glycolysis, 2 from CAC, 28 from ETC

Question 25

what happens if a cell has no oxygen during the electron transport chain?

Answer 25

-electrons cannot get collected at the end of the chain
-ETC cannot occur

Question 26

what is the purpose of fermentation in humans?

Answer 26

-to regenerate NAD+ from NADH to allow for glycolysis to continue
-to remove pyruvate by converting it to lactic acid so it can be removed as a waste product