Cell Structure and Function Exam 2 Questions
and Verified Answers
Why does a cell need energy— Correct Answer: For work... to maintain order, work against 2nd law of
thermodynamics
What is source of cellular energy?— Correct Answer: Carbs --> sugars (hexoses and pentoses, 5C and 6C
sugars)
Lipids --> fatty acids and glycerol
Proteins --> amino acids
Glucose (carbs) 38 ATP
Lipids (fatty acids) 51 ATP, glycerol (19 ATP)
How do we use the energy stored?— Correct Answer: Use metabolic pathways to take energy from
sources to make ATP
Energy Sources— Correct Answer: Catabolic - break down; generate energy; make ATP
Anabolic - build up; requires energy; use ATP
ΔG free energy— Correct Answer: Exergonic - Will occur spontaneously, -ΔG
Endergonic - Will not occur spontaneously, +ΔG
Glucose— Correct Answer: We want energy from the C-H bonds
Glucose is full of high energy electrons
Oxidation and Reduction— Correct Answer: Redox rxns involve transfer of an electron from one
molecule to another
Oxidation is loss of electron (OIL)
Reduction is gain of electron (RIG)
, THE REDUCED FORM HAS STORED ENERGY AND OXIDATION IS USED TO GET THAT ENERGY
In biological redox rns, electrons are transferred by transfer of H atoms.
H = 1 proton (H+) + 1 electron
H+ is not H
Example:
AH + B --> A + BH
A is oxidized and B is reduced
If oxygen is available— Correct Answer: Eukaryotes can make as many as 36 ATP/glucose
ATP --> ADP + Pi ΔG0' = -7.3 kcal/mol
36x7.3=262.8 and 38% of kcal go to "useful energy"
Succinate to Fumarate— Correct Answer: Succinate loses 2e- and 2H+ (OXIDATION)
FAD to FADH2 (REDUCTION)
Modified nucleotides that serve as e- shuttles— Correct Answer: NAD+ --> NADH
FAD --> FADH2
These products are "high energy e-" in the reduced forms
Reactants can accept 2e- (that is how they get reduced)
Coupled reactions— Correct Answer: Linking reactions (one has -ΔG and one has +ΔG)
As long as abs value of -ΔG is larger than abs value of +ΔG, it will have enough energy to go
Process of glycolysis— Correct Answer: See printout
and Verified Answers
Why does a cell need energy— Correct Answer: For work... to maintain order, work against 2nd law of
thermodynamics
What is source of cellular energy?— Correct Answer: Carbs --> sugars (hexoses and pentoses, 5C and 6C
sugars)
Lipids --> fatty acids and glycerol
Proteins --> amino acids
Glucose (carbs) 38 ATP
Lipids (fatty acids) 51 ATP, glycerol (19 ATP)
How do we use the energy stored?— Correct Answer: Use metabolic pathways to take energy from
sources to make ATP
Energy Sources— Correct Answer: Catabolic - break down; generate energy; make ATP
Anabolic - build up; requires energy; use ATP
ΔG free energy— Correct Answer: Exergonic - Will occur spontaneously, -ΔG
Endergonic - Will not occur spontaneously, +ΔG
Glucose— Correct Answer: We want energy from the C-H bonds
Glucose is full of high energy electrons
Oxidation and Reduction— Correct Answer: Redox rxns involve transfer of an electron from one
molecule to another
Oxidation is loss of electron (OIL)
Reduction is gain of electron (RIG)
, THE REDUCED FORM HAS STORED ENERGY AND OXIDATION IS USED TO GET THAT ENERGY
In biological redox rns, electrons are transferred by transfer of H atoms.
H = 1 proton (H+) + 1 electron
H+ is not H
Example:
AH + B --> A + BH
A is oxidized and B is reduced
If oxygen is available— Correct Answer: Eukaryotes can make as many as 36 ATP/glucose
ATP --> ADP + Pi ΔG0' = -7.3 kcal/mol
36x7.3=262.8 and 38% of kcal go to "useful energy"
Succinate to Fumarate— Correct Answer: Succinate loses 2e- and 2H+ (OXIDATION)
FAD to FADH2 (REDUCTION)
Modified nucleotides that serve as e- shuttles— Correct Answer: NAD+ --> NADH
FAD --> FADH2
These products are "high energy e-" in the reduced forms
Reactants can accept 2e- (that is how they get reduced)
Coupled reactions— Correct Answer: Linking reactions (one has -ΔG and one has +ΔG)
As long as abs value of -ΔG is larger than abs value of +ΔG, it will have enough energy to go
Process of glycolysis— Correct Answer: See printout
