Cellular Respiration

Cellular Respiration

Glycolysis

• Takes place in cytoplasm

• Breaks a glucose molecule into 2 pyruvic acid molecules

• Produces 2 ATP & 2 NADH

Krebs Cycle

• Occurs in mitochondria and must run 2 times to complete the metabolism of glucose

• Involves the breakdown of pyruvic acid into carbon dioxide

• Produces 2 ATP, 8 NADH, and 2 FADH₂

Electron Transport Chain

• Involves the build up of a concentration gradient to use the energy released via diffusion to make ATP

• NADH and FADH₂ release hydrogens that give up electrons ("free electricity") to power the active transport of H⁺

• Requires oxygen to complete the process (aerobic process)

• Produces water and large amounts of ATP

Poll

What are the consequences of a proton gradient?

• To create an environment with a different pH

• To create an electrical charge across a membrane

• As a form of potential energy storage

• To power chemical reactions like the spinning of a flagellum, the transport of ions and molecules across a membrane, and the synthesis of ATP

What important characteristic of the inner membrane allows for this gradient to be established and maintained?  

Semi-permeability - the lipid bilayer's nonpolar zone prevents the H⁺ ions from diffusing back through the membrane

Multiple Choice

If you “poke a hole” in the inner membrane such that protons can freely move across it, what would happen to the proton distribution across the inner membrane?

• It will not change

• the concentration gradient will get larger as protons move across the membrane

• the protons will diffuse back across the membrane dissipating the concentration gradient

Multiple Choice

If you “poke a hole” in the inner membrane such that protons can freely move across it, what would happen to the amount of ATP produced by the mitochondria?

• it will increase

• it will decrease

• it will remain the same

Open Ended

Most ATP is consumed soon after its production. The cell has ways of detecting how much ATP is produced and needs to keep its supply constant.

If you poke a hole through the inner membrane, what might the cell do to try to adapt to the change and reestablish previous levels of ATP?

Multiple Select

What happens to ATP and glucose oxidation levels in response to treatment with DNP

• they are balanced

• they don't change

• glucose oxidation increases

• ATP levels decrease

What could cause the effects shown in the graph?

Remember that DNP is a “mitochondrial uncoupler.” An uncoupler is a chemical that disconnects two linked biological processes.

Multiple Select

Review the list of physiological effects that DNP has on the body (list as many as possible). Which of these effects are energy-related?

• weight loss

• fever

• cataracts

• rash

Multiple Select

What linked processes does DNP uncouple?

• glycolysis

• Krebs cycle

• proton gradient

• ATP synthesis

Uncoupling

By introducing a 'hole' in the mitochondrial membrane, the proton gradient will dissipate. If this occurs, then the protons can't be used for ATP production. The cell will respond by increasing the metabolism of glucose to try to make up for the lack of ATP.

Open Ended

For an athlete, what are the consequences of ATP depletion?

Poll

Should Connor take DNP to lose weight?

• Yes

• No