Lecture 6 Cellular Metabolism

Question 1

Glucose

Answer 1

high energy molecule that we start with
primary substrate(monomer) for cellular respiration
required by brain and CNS

Question 2

ATP

Answer 2

the energy currency molecule

energy contained in phosphate group

Question 3

Pyruvate

Answer 3

end product of glycolysis
branch point between aerobic and anaerobic metabolism
glucose split into two = pyruvate

Question 4

Lactate

Answer 4

end product of anaerobic metabolism

Question 5

Acetyl CoA

Answer 5

the 2 carbon shuttle

a key intermediate in aerobic metabolism

Question 6

NAD+

Answer 6

oxidized coenzyme (also FAD)
lost its electrons, low energy form

Question 7

NADH

Answer 7

reduced coenzyme (also FADH2) 
carrier of 2 high energy electrons

Question 8

O2

Answer 8

the final electron acceptor in aerobic metabolism

Question 9

CO2

Answer 9

end product of aerobic metabolism

Question 10

H20

Answer 10

other end product of aerobic metabolism

Question 11

Oxidation of glucose

Answer 11

glucose + 6 02 –> 6CO2 + 6H20 + energy ->ATP,Heat

Question 12

Cellular respiration

Answer 12

metabolism of substrates to release energy to form ATP

Question 13

Hexokinase

Answer 13

adds phosphate group to glucose

Question 14

phosphofructokinase

Answer 14

adds phosphate to fructose making it have 2 phosphates major regulatory enzyme

Question 15

Glycolysis

Answer 15

partial breakdown of glucose to pyruvate. glucose -> 2 pyruvate
occurs in cytosol
multi step pathway

Question 16

Energy investment step in glycolysis

Answer 16

adds 2 high energy phosphates from ATP

input 2 ATP

Question 17

Cleavage step in glycolysis

Answer 17

splits 6C sugar into two 3C molecules

Question 18

Energy capture step in glycolysis

Answer 18

yield 2 NADH and 2 ATP

Question 19

NADH in glycolysis

Answer 19

each carries two high energy electrons

NAD+ + 2H (oxidized) –> NADH + H+ (reduced)

Question 20

Aerobic metabolism

Answer 20

pyruvate goes to transition step and then CAC in the mitochondria
NADH donates electrons to the ETC
Requires oxygen

Question 21

Glycolysis aerobic metabolism net yield and product

Answer 21

yield: 2 ATP and 2 NADH per glucose
Product: 2 Pyruvate

Question 22

Anaerobic metabolism

Answer 22

pyruvate is converted to lactate via the lactic acid pathway in the cytosol
NADH is converted back to NAD+ needed to continue glycolysis
oxygen is being reduced while NADH is being oxidized

Question 23

Glycolysis anaerobic metabolism net yield and product

Answer 23

Yield: 2 ATP per glucose
Product: 2 lactate + 2H+

Question 24

Transition step form glycolysis to the Citric Acid Cycle

Answer 24

yield: 1 NADH
product: 1 CO2
acetyl CoA is a key intermediate which transfers 2C units to the Citric Acid Cycle

Question 25

Citric Acid Cycle

Answer 25

occurs in matrix of mitochondria
First step: 2C unit from acetyl CoA combines w/ oxaloacetate(4C) to form citrate (6C)
Second Step: citrate is oxidized back to oxaloacetate
2 Carbon atoms are fully oxidized to form 2 CO2 molecules

Question 26

Net yield and product of Citric Acid Cycle

Answer 26

yield: 3 NADH + 1 FADH2 + 1 ATP
Product: 2 CO2

Question 27

Electrons in the Citric Acid Cycle

Answer 27

high energy electrons are transferred to NADH and FADH2 and carried to the ETC

Question 28

ETC

Answer 28

electron carrier proteins are located in the INNER membrane of the mitochondria
3 major protein complexes (1,3,4)
NADH and FADH2 donate high enery electrons to the ETC
electrons move downhill through ETC release energy for ATP production
02 is the final electron acceptor

Question 29

cytochromes

Answer 29

iron-containing proteins in the ETC

Question 30

ATP synthesis

flow of H+

Answer 30

Chemiostatic coupling mechanism:
ETC complexes act as H+ pumps
H+ is pumped uphill from the matrix into the intermembrane space containing high [H+]
H+ moves back downhill through the ATP synthase in the inner membrane
ATP synthase phosphorylates ADP to ATP

Question 31

Complete oxidation of glucose yield and product

Answer 31

yield: about 30 ATP per glucose

End product: 6 CO2 + 6 H20