Exam 1 (Metabolism) Flashcards
What are the inputs and products of the Krebs Cycle (per one molecule of pyruvate)?
inputs:
- acetyl CoA (2C)
- 3 NAD+
- FAD
- GDP
products:
- oxaloacetate (4C)
- 3 NADH
- FADH2
- 2 CO2
- ATP
What is the difference between tonicity and osmolarity?
tonicty compares a cell to the solution it’s in; osmolarity compares two solutions
How does the integrating center function in homeostasis?
- comparator compares info from sensor to known set point
- effector triggers any necessary response
What is the P:O ratio, and what is its normal value?
ATP formed per O reduced to H2O;
normal = 3 (fully coupled)
abnormal = 0 (fully uncoupled)
What are the inputs and products of glycolysis?
inputs:
- glucose
- 2 ATP
- 2 NAD+
products:
- 2 pyruvate
- 2 NADH
- 4 ATP
How does anaerobic glycolysis differ from aerobic glycolysis?
pyruvate is the final electron acceptor; turned into lactate by lactate dehydrogenase
What does sodium azide affect and how?
irreversibly inhibits complex IV
What factors increase membrane fluidity?
- higher temperature
- less cholesterol
- more double bonds in phospholipid tails
- shorter phospholipid tails
What can change the composition of phospholipids in the cell membrane?
Phospholipases
What are the two types of membrane protein involved in facilitated diffusion?
channel and carrier proteins
What does lactate dehydrogenase do, and why is it important?
converts pyruvate to lactate
regenerates NAD+
in reverse, it converts lactate to pyruvate
What are some types of non-penetrating solutes?
ions, large molecules, etc.
How many molecules of Na+ and K+ are pumped by the Na+/K+ pump, and in what direction? What else is used?
3 Na+ are pumped out
2 K+ are pumped in
1 ATP reduced to ADP
What is a reactive oxygen species (ROS)?
oxygen free radical formed by premature theft of electrons from ETC; possible because of minimal E’ difference between CII, Q, and CIII
What is the respiratory quotient (RQ)?
can be used to determine fuel type
What enzyme facilitates the bicarbonate reaction?
CO2 + H2 -carbonic anhydrase-> H2CO3 –> H+ + HCO3-
What is the name and transport type of the glucose transporter used in facilitated diffusion?
What happens after exercise?
excess post-exercise O2 consumption (EPOC)
lactate –> pyruvate
Mb replenished
How fast do the various ATP production mechanisms run out in oxygen deficit?
- stored ATP: 1-2 s
- phosphogens: 5-10 s
- stored O2: ~30 s
- anaerobic glycolysis: ~60 s
What are the two subunits of LDH, and what are their affinities?
- M: pyruvate affinity; anaerobic environment
- H: lactate activity; aerobic environment
- LDH is some combination of 4 of the 2 types
What enzyme regulates whether or not glycolysis or glycogen sythesis occurs? How?
phosphofructokinase; it is allosterically regulated by ATP; HIGH levels of ATP shut it off
What are some types of penetrating solutes?
urea and glucose
How does Na+/K+ ATPase work?
What are the products of the G3P –> pyruvic acid process?
1 NADH; 1 ATP (per 1 molecule of G3P)
What are the inputs and products of beta-oxidation?
inputs:
- ATP
- NAD+
- FAD
- 2C hydrocarbon
products:
- ADP
- NADH
- FADH2
- acetyl CoA
How many ATP are produced from 1 molecule of NADH and FADH2 respectively?
3 ATP from 1 NADH
2 ATP from 1 FADH2
What does osmolarity measure?
of particles per liter
comparison between 2 solutions
What happens to the hydrocarbon chains of fatty acids?
beta-oxidation; 2C at a time are cut off and turned to acetyl CoA
What does dinitrophenol do?
decoupling agent; allows H+ through membrane without passing through ATP synthase
What is the effect of exogenous antioxidants?
antioxidants from diet; block some of the chain reactions that constitute and cause oxidative damage
What are the four mechanisms of ATP production?
- aerobic catabolism
- anaerobic glycolysis
- Pi stores (phosphogens)
- oxygen stores in muscles (Mb; Hb)
What is a facultative anaerobe?
organism that uses oxygen when it is available, but can survive without it
What active transport protein imports glucose, and what other molecule is used?
What is the Cori Cycle?
lactate metabolism
glucose <–> pyruvate <–> lactate
net 4 ATP loss
What enzyme converts glucose to G6P and what is the purpose of this?
hexokinase; gets rid of glucose to preserve the gradient that keeps glucose moving into the cell
What are the inputs and products of pyruvate processing (one pyruvate molecule)?
inputs:
- pyruvate
- NAD
- coenzyme A
products:
- acetyl CoA
- NADH
- CO2
What is the effect of endogenous antioxidants?
internal repair systems; block ROS formation
What is the important pathway of the Krebs Cycle?
acetyl CoA (2C) –> citrate (6C) –> oxaloacetate (4C)
What does cyanide affect and how?
reversibly inhibits complex IV
What is the difference between substrate-level and oxidative phosphorylation?
substrate-level: chemical energy –> chemical energy
oxidative: chemical energy –> membrane gradient –> chemical energy
What process happens when glucose is needed?
gluconeogenesis
How do phosphate stores work?
creatine phosphate + ADP -creatine kinase-> creatine + ATP
What happens to the lactate formed in anaerobic glycolysis?
can be used in gluconeogenesis; can enter the Krebs Cycle
What is the main pathway of homeostasis?
stimulus –> integrating center –> response
What is the equation for metabolic rate?
MR = VO2(ml O2/gh) x (kJ/LO2) x (1/1000 ml)
What happens to the energy carriers (NADH and FADH2) that are generated during glycolysis, pyruvate processing, and the Krebs Cycle?
go to the electron transport chain
Where is glycogen stored?
liver; muscles
What does rotenone affect and how?
competitively inhibits complex I; still allows for NAD+ regeneration but blocks electron pumping
What happens to the sugar of triglycerides?
glycerol is turned into glyceraldehyde 3 phosphate (requires 1 ATP and generates 1 NADH), which is turned into pyruvate
What are the ATP synthase conformations?
- loose (ADP + Pi)
- tight (ATP formation)
- open (ATP leaves)
1 spin makes 3 ATP
