9.1 oxidation and reduction in cellular respiration

Question 1

cellular respiration redox equation

Answer 1

• -glucose is oxidized
• -oxygen is reduced

–glucose combines with O2 and energy is released as electrons associate with Hydrogen transfer to a lower energy state

Question 2

what releases energy

Answer 2

the electrons lose energy as they are transferred

Question 3

why are organic molecules with hydrogen good fuel

Answer 3

they release energy when the electrons “fall down the energy gradient”
and are transferred to oxygen

Question 4

are Hydrogens transferred directly to oxygen in cellular respiration

Answer 4

no

they pass through electron carrier NAD+ first

Question 5

NAD+

Answer 5

a coenzyme
electron carrier
oxidizing agent during cellular respiration

Question 6

how does NAD+ accept electrons?

Answer 6

enzyme called dehydrogenates remove 2 hydrogen atoms from glucose (oxidizing it)

2 protons
and
2 e-

then it delivers 2 electrons and 1 proton to NAD+
–the other proton is release as H+ in to the surroundings

–the charge on NAD+ is neutralized and changed its name to NADH

Question 7

how does hydrogen and oxygen combine to form energy in cellular respiration

Answer 7

it combines to make a lot of energy that uses and electron transport chain to break the “fall” into several energy releasing steps

Question 8

the ETC

Answer 8

NADH shuttles electrons from glucose to the top of the ETC

• • at the bottom, O2 captures the electrons (b/c of its affinity for electrons) as well as hydrogen nuclei (H+) to form water
• electrons cascade down the ETC losing energy in small amounts at each step

Question 9

how does the ETC work

Answer 9

each step is more electronegative than the previous so they can oxidize the uphill neighbor

–O2 is at the bottom to receive the more stable electrons in the end