electron transport chain

What are the two main stages of oxidative phosphorylation?

the electron transport chain and chemiosmosis

What is the main purpose of the electron transport chain

Where in the mitochondrion does the electron transport chain occur

the intermembrane space

which electron transporters are oxidised while delivering electrons to protien complexes

NADH FAS

How many ATP does oxidative phosphorilisation create

28. (32 when you add glycolosis)

what is the final electron acceptor and what does it make

O2 and h20

where does the process take place

th inner mitochondrial membrane.

what is the electrochemical gradient mde by using hte hydrogens pumped into the ims called

the proton motive force

what is the [roton motive force used for

to power atp synthase

what are the two kinds of fermentation

alcahol and lactic acid

what does fermentation do

allows atp production without oxygen

how many atp does fermentation make vs oxidative phosphoralistion

2 vs 32

what does fermentation use

glycolosis

what are the waaste products of fermentation

alcohol, or lactic acid

What is the main purpose of the electron transport chain?

The electron transport chain transfers electrons from NADH and FADH2 to oxygen through a set
of protein complexes, while also pumping protons (H+) across the inner mitochondrial
membrane.

What happens to NADH at Complex I in the electron transport chain

NADH is oxidized to NAD+, donating two electrons to Complex I. These electrons are passed
along the chain, and Complex I pumps protons into the intermembrane space

Which complex accepts electrons from FADH2

Complex II

why does FADH2 produce less ATP than NADH?

Because FADH₂ donates its electrons to Complex II, which does not pump protons, so fewer
protons are moved across the membrane. As a result, FADH₂ yields about 1.5 ATP, whereas
NADH yields about 2.5 ATP.

Which complexes pump protons across the membrane?

Complexes I, III, and IV pump protons across the inner mitochondrial membrane.

What happens if protons leak back across the membrane without going through ATP
synthase?

ATP production drops or stops; energy is lost as heat due to dissipation of the proton gradient

What kind of energy transformation occurs in ATP synthase?

ATP synthase converts potential energy in the proton gradient into chemical energy stored in
ATP. More specifically, this is a transformation from electrochemical energy → mechanical
rotational energy → chemical bond energy (ATP

What happens to the ATP produced in the mitochondrial matrix?

ATP produced in the matrix is exported to the cytoplasm to be used for cellular work
(biosynthesis, transport, muscle contraction, etc.).

What is the overall purpose of photosynthesis?

to use light energy to convert carbon dioxide and water into
sugars that store chemical energy.

What are the two main stages of photosynthesis,

Light (dependat) reactions. and light independant (calvin cycle) dark reactions

what happens in the light reactions

hese occur in the thylakoid membranes. Light energy is absorbed by chlorophyll and used to
split water (H₂O), releasing oxygen (O₂), protons (H⁺), and electrons. The electrons move
through the photosynthetic electron transport chain, generating a proton gradient that drives
ATP synthase to make ATP. Electrons also reduce NADP⁺ to form NADPH. The ATP and NADPH
produced here provide energy and reducing power for the second stage

what happens int. he dark reactions

these occur in the stroma. The ATP and NADPH from the light reactions are used to fix carbon
dioxide (CO₂) into organic molecules. Through a series of enzyme-catalyzed steps (the Calvin
cycle), carbon is converted into simple sugars that can be used for energy and growth

What are the main parts of a chloroplast,

inner and outer membranes, stroma, thylakoid membranes, thylakoid lumen, granum

Outer and inner membranes:

These form the chloroplast envelope, a double membrane that controls the movement
of molecules in and out of the chloroplast.

stroma

the fluid-filled space inside the inner membrane that surrounds the
thylakoids. contains enzymes, DNA, and ribosomes. The light-independent reactions
(Calvin cycle) occur here, using ATP and NADPH to fix CO₂ into sugars

Thylakoids:

Thylakoids are flattened membrane sacs arranged in stacks called grana. The thylakoid
membranes contain chlorophyll/ pigments that capture light energy.

light-
dependent reactions take place here, where light energy drives the splitting of water
and the production of ATP and NADPH.

Thylakoid lumen:

The space inside the thylakoid sacs. Protons (H⁺) are pumped into the lumen during the
light reactions, creating the proton motive force that drives ATP synthesis

Granum (plural: grana):

A stack of thylakoids that increases the surface area for light absorption and the light
reactions

Why is the thylakoid membrane so important for photosynthesis?

The thylakoid membrane holds the photosystems, electron transport chain, and ATP synthase
that carry out the light-dependent reactions.

What is the role of light energy in photosynthesis?

it powers the light dependent reactions by exiting the electrons in the cholorphyll molecules

Why do plants still need mitochondria if they can make ATP in light reactions

the atp from the light reactions stay in the chloroplasts. the mitochindira turn sugar into atp for the rest of the processes

What is chlorophyll, and what are its main structural parts?

Chlorophyll is the main pigment that absorbs light energy for photosynthesis. It has a ring-
shaped region that captures light and a long tail that keeps it anchored in the thylakoid
membrane. The ring contains a metal ion that helps absorb specific wavelengths of light

what is a phototsystem

A photosystem is a large protein–pigment complex in the thylakoid membrane that captures
light energy and converts it into chemical energy

How do antenna pigments transfer energy to the reaction center

Antenna pigments absorb photons and pass the excitation energy to neighboring pigments by
resonance energy transfer, without transferring electrons. The energy is funneled toward the
reaction center chlorophylls, where it excites electrons that are then transferred to an electron
acceptor.

Why are two photosystems needed instead of one?

wo photosystems are needed because a single photon of light does not provide enough
energy to move electrons from water to NADP⁺

What happens in photosystem I?

Photosystem I absorbs light to re-energize electrons arriving from the cytochrome complex

What is the final electron acceptor of the light reactions?

The final electron acceptor of the light reactions is NADP⁺, which is reduced to NADPH by

What does the cytochrome b6f complex do?

The cytochrome b₆f complex (an accessory protein complex) transfers electrons between the
two photosystems and pumps protons (H⁺) into the thylakoid lumen. This creates the proton
gradient that drives ATP synthesis

2. What is the role of photosystem II in this flow?

Photosystem II captures light energy to oxidize water, releasing oxygen, protons, and electrons.
It provides the first high-energy electrons that enter the transport chain and begin the process
of building a proton gradient for ATP production

What is the overall direction of electron flow through the photosynthetic ETC?

Overall direction: H₂O → PSII → PQ → cytochrome b₆f → PC → PSI → Fd → NADP⁺