Test 4, Lecture 2

After NADH is produced from the process of glycolysis, which statement does not describe how can it be used within the cell?

After NADH is produced from the process of glycolysis, which statement does not describe how can it be used within the cell?

NADH is a carrier of electrons and delivers H+ to the electron transport chain, where it then becomes NAD+ to be recharged. ****

Once glycolysis is complete, the first step within the first process of aerobic respiration is the oxidation of pyruvate. Where in the mitochondria does this process take place?

Intermembrane space

Once glycolysis is complete, the first step within the first process of aerobic respiration is the oxidation of pyruvate. What is the equation of this process? (i.e. know the reactants and products we discussed and the equation which was on the board)

Pyruvate + NAD(+) + CoA → Acetyl-CoA + CO(2) + NADH

After pyruvate oxidation is complete, acetyl Co-A is produced. Which statement describes a way acetyl-CoA can be used within your body? (we discussed two main ways)

• If your ATP levels are low, you can send the acetyl-CoA to the krebs cycle

  • Reason for fat storage

• If you have too much energy, high amounts of ATP, your body will send a trigger to stop making acetyl CoA/ATP and instead uses it for lipids

  • Lipid synthesis

After pyruvate oxidation is complete, acetyl Co-A is produced. Acetyl Co-A can then be used within your cells in two main ways. _______ takes place if the ATP level is high within the cell and ________ takes place if the ATP level is low within your cell. Fill in the blanks.

Lipid Synthesis, Krebs Cycle

Which statement describes any steps, reactants, or products of segment A of the Krebs cycle?

4-C + Acetyl-CoA → Citrate + CoA

• Oxaloacetate: 4 carbon molecules

• Bonded together because of CoA

• Can be used in pyruvate oxidation

• Citrate (6-carbon molecule) and citric acid cycle

  • Not very stable, naturally wants to break down

  • From there, we can do a bunch of oxidation steps

• Goes from 4 to 6 carbon molecules

Which statement describes any steps, reactants, or products of segment B of the Krebs cycle?

• Starting off with 6-carbon molecule: citrate

• Oxidizing two times in a row (Start with 6 carbons end with 4)

• First time you are Oxidized and decarboxylated

  • Citrate → 5-C + NADH + CO₂

• Second time, decarbolyxation and oxidation

  • 5-C → 4-C + NADH + CO₂+ 2 ATP

• 6 to 4 carbon molecules

Which statement describes any steps, reactants, or products of segment C of the Krebs cycle?

• 4-C → FADH₂ + NADH 4-C

• Oxidizes even further

  • Oxidation is taking place and you are removing some hydrogens changing some double bonds around

  • That's when you produce NADH and FADH2

• Structurally, it changes

• No decarboxylation

• Carbon molecules do not change

What is the proper order of the enzymes and carriers used within the electron transport chain?

• NADH dehydrogenase (enzyme)

  • Removes hydrogen from NADH

  • Supplying some of the electrons, reduction

  •  Oxidizing the NADH and you're putting the H's back into the gradient of the matrix itself

• Ubiquinone (Q) (carrier)

  • Carrier for electrons from one ennzyme to another enzyme

  • Takes electron energy and carries it to power the next one

    • Sort of like a wire with electricity

• BC₁ complex 

  • Operates as a proton pump

  • Drives as many hydrogens as possible in the intermembrane space

  • Sometimes goes against the concentration gradient

• Cytochrome C (carrier)

  • Also a carrier

  • Carries electrical energy from BC1 complex

  • Carries energy along the chain

• Cytochrome Oxidase

  • Drive as many hydrogens as humanly possible

  • Leftover energy will be used to make water because oxygen is present in large amounts

 The electron transport chain is an area the accepts the electrons transferred within the mitochondria that consist of a series of membrane-associated proteins. ________ is an enzyme imbedded in the membrane which is first to obtain the electrons and remove the hydrogens attached to them. Fill in the blank.

NADH dehydrogenase

The electron transport chain is an area the accepts the electrons transferred within the mitochondria that consist of a series of membrane-associated proteins. ________ is a carrier which passes the electrons along the chain from the NADH hydrogenase to the BC1 complex. Fill in the blank.

Ubiquinone

The electron transport chain is an area the accepts the electrons transferred within the mitochondria that consist of a series of membrane-associated proteins. _______ is a protein-cytochrome complex which operates as a proton pump, driving protons out across the membrane. Fill in the blank.

BC₁ complex

The electron transport chain is an area the accepts the electrons transferred within the mitochondria that consist of a series of membrane-associated proteins. ________ is where oxygen and hydrogen combine to form water (not all H+ get put into the intermembrane space). Fill in the blank.

Cytochrome Oxidase

Which statement accurately describes how the ATP is produced at the end of the ETC (know ALL information we discussed about the proton gradient and how it works)?

Due to the proton gradient created from H+ within the cell membrane, the H+ shoots out of the ATP synthase to get to the area of low concentration. This powers the ATP synthase like a motor and generates ATP in the process.

During the process of ____________, a chemical formation of ATP is driven by a diffusion force similar to osmosis. Fill in the blank.

chemiosmosis

The electron transport chain is an area the accepts the electrons transferred within the mitochondria that consist of a series of membrane-associated proteins. What is the function of ATP synthase within the ETC?

• Where you're making ATP in extremely large amounts

• Driving a concentration gradient of hydrogens (?)

Which statement does not describe a step of the electrons transport chain (ETC)?

• Electrons harvested and carried

• Electron energy

• Oxygen and Protons

• Proton gradient and ATP

What is the theoretical and actual yield of ATP produced by aerobic respiration in eukaryotes?

• Theoretical Yield: 36 ATP

• Actual Yield: Close to 30

Why is the actual yield of ATP produced during aerobic respiration less than the theoretical yield which should occur? (know the two reasons we discussed in class)

1. The inner mitochondrial membrane is sometimes leaky. protons can go in and out of a membrane, they need to be pumped in in high quantities. they can escape

2. often uses this diffusion gradient in the mitochondria for things other than chemiosmosis

Due to varying reasonings discussed in class, aerobic respiration only uses _______ (percent) of energy within one original glucose molecule. Fill in the blank.

32

Aerobic respiration has different control points along its enzymatic pathway to not allow it to continue unless needed. One of the first control points occurs during glycolysis using the enzyme called phosphofructokinase. What things occurring in your cell can turn this enzymes on and off? (know all the conditions we discussed in class)

• Catalyzes the conversion of fructose phosphate to fructose biphosphate

• High ADP and Low ATP → it will trigger it to turn on

• Low ADP and High ATP → turns off

• Inhibits it

Aerobic respiration has different control point along its enzymatic pathway to not allow it to continue unless needed. The second control point occurs right before the Krebs cycle begins using the enzyme called pyruvate dehydrogenase. What things occurring in your cell can turn this enzymes on and off? (know all the conditions we discussed in class)

• Converts pyruvate to acetyl-CoA

• Removes some oxygens and carbons

  • Low levels of citrate (and it’s needed) in the krebs cycle → turns it on

  • High levels of citrate → off

• NADH inhibition

  • High levels inhibit it from turning on

  • Low levels → turn on

Aerobic respiration has different control points along its enzymatic pathway to not allow it to continue unless needed. The third control point occurs at the beginning of the Krebs cycle using the enzyme called citrate synthase. What things occurring in your cell can turn this enzymes on and off? (know all the conditions we discussed in class)

• Citrate synthase

  • ATP inhibition

    • If you have high ATP, you don’t need this to work

    • Low levels of ATP → needs this to work/turn it on

• Catalyzes first reaction in Krebs (Conversion of 4-C molecule + acetyl CoA into citrate)

According to the Fermentation video, which of these is not the four kinds of cells that can handle the no oxygen environment (i.e. do not have to complete aerobic cellular respiration)?

Four Cells that can Handle no oxygen

• Bacteria

• Yeast

• Archaea

• Muscle cell for a while

According to the Fermentation video, some organisms can still complete glycolysis and the Krebs cycle under aerobic conditions, but what do they use as the electron acceptor instead of oxygen?

Sulfate

According to the Fermentation video, does fermentation produce more or less ATP than aerobic respiration? (and also know why)

Less; Requires ATP to start and no ETC(?)

According to the Fermentation video, fermentation ends a little step at the end of glycolysis to deal with the excess of NADH molecules and to regenerate NAD+. How does alcoholic fermentation deal with these NADH and the two pyruvates made during glycolysis?

• Regenerates NAD+

• The 2 pyruvate is used which will ultimately produce carbon dioxide and 2 ethanol (alcohol),

• Acetaldehyde, can act as an electron acceptor

• 2 NADH is oxidized to 2 NAD+