Anonymous asked in Science & MathematicsBiology · 1 month ago

I need help with Bio 20?

1).On each step in the electron transport system chain, a small charge is produced that will be used to synthesize ATP. When the electrons leave the chain in pairs, they combine with oxygen (the final electron acceptor) to form water. During the process water is....

A.) Reduced because electrons are gained

B.) Reduced because electrons are lost

C.) Oxidized because electrons are gained

D.) Oxidized because electrons are lost

2).If oxygen is absent during cellular respiration, then

A.) Cellular respiration functions as it would with oxygen

B.) A different electron acceptor is used and the energy produced is less then with o2

C.) No energy results because cellular respiration cannot function

D.) A different electron acceptor is used and the energy produced is not affected

3).In light dependent reactants, the transfer of energy through electrons produces a hydrogen ion concentration gradient. Many more hydrogen ions are in the thylakoid space than in the stroma. The process that occurs when these electrons pass back to the stroma through a specialized channel is....

A.) An electron transport chain and creates NADPH

B.) An electron transport chain and creates NADPH

C.) Called chemiosmosis and requires ATP

D.) Called chemiosmosis and produces ATP

I missed a few weeks of school due to sickness and I am struggling to catch up with online school. It would be much appreciated if someone could please answer these and elaborate a bit. :) :)

1 Answer

  • 1 month ago
    Favorite Answer

    1)- A, because oxygen was reduced to make water. Remember that oxidation = loss of electrons, gain of oxygen, or loss of hydrogen atoms. Reduction is the opposite: gain of electrons, loss of oxygen, and gain of hydrogen.

    in the final step of the electron transport chain, Oxygen accepts (gains) electrons to form water. If you compare Oxygen (O2) to water (H2O), you'll notice we also gained hydrogen and lost oxygen. This is consistent with reduction.

    2) B. If oxygen isn't available, the mitochondria switches to anaerobic respiration (glycosis) to produce energy. In this case, pyruvate is the final electron acceptor. Another name for anaerobic respiration is fermentation. In animals, the pyruvate is reduced into lactate. In other types of cells like yeast, it's reduced into ethanol. The energy generated by glycolysis is much much less than the electron transport chain, so energy production is definitely affected.

    3) D. This process describes chemiosmosis which produces energy (ATP). Note that both NADPH and ATP are produced in the light reaction, but through different mechanisms.

    Hope that helped, feel better soon.

    there's some great channels on YouTube available to help with cellular respiration nd photosynthesis. You should check them out: Crashcourse, AK lectures, dirty medicine, amoeba sisters, and bozeman science.

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