Essential Cell Biology Chapter 14: Energy Generation in Mitochondria and Chloroplasts (Question)

A carrier molecule of lower electron affinity to a carrier molecule of high electron affinity.

As electrons move through the electron transport chain, they are passed from:

Red

Chlorophyll molecules absorb which color of light most strongly?

Starch

During very active periods of photosynthesis, the glyceraldehyde-3-phosphate generated by carbon fixation in the stroma is stored as:

Bacteria engulfed by ancestral cells

How did organelles that produce ATP in eukaryotic cells evolve?

A very low electron affinity

How large is the electron affinity of NADH?

O2

In Earth's history, with the rise of cyanobacteria, what molecule began accumulating in the atmosphere for the first time?

Mitochondrial inner membrane

In a eukaryotic cell, where are most of the proteins for the electron transport chain located?

Molecular oxygen (o2)

In mitochondria, what is the final electron acceptor in the electron transport chain?

30

In mitochondria, with the complete breakdown of glucose, about how many molecules of ATP can be produced for each molecule of glucose and oxidized?

A proton gradient across the thylakoid membrane

In photosynthesis, what drives generation of ATP by ATP synthase?

NADP+

In the electron transport chain in chloroplasts, which molecule serves as the final electron acceptor?

Pump protons across a membrane

In the electron transport chain, as electrons move along a series of carriers, they release energy that is used to:

H2O

In the electron transport chain, what provides the main reservoir for protons that are pumped across the membrane?

From the intermembrane space to the mitochondrial matrix

It is energetically favorable for protons to flow in which direction?

Donate electrons

NADH has a strong tendency to do what with electrons?

Reduces N2 to ammonia (NH3)

Nitrogen fixation:

Sugars

Photosynthesis allows plants to capture energy from sunlight to produce:

Oxidative phosphorylation

Stage 1 of photosynthesis is in large part equivalent to what?

True

T/F: Electrons start out at a very high energy and lose energy at each transfer step.

False.

T/F: Glucose is a direct source of fuel for mitochondria.

True.

T/F: In chloroplasts the pigment chlorophyll donates electrons to an electron transport chain in the thylakoid membrane.

True

T/F: Mitochondria can change their location, shape, and number in the cell to suit the needs of the cell.

True

T/F: NADH has a weak affinity for electrons and a negative redox potential

False (bacteria do not.)

T/F: Plants, animals, bacteria, and eukaryotic microorganisms all have mitochondria.

True

T/F: The chlorophyll special pair in photosystem I actually serves as the final electron acceptor in the photosynthetic electron-transport chain.

True

T/F: The outer membrane of a mitochondrion is permeable to all small molecules, including small proteins.

True

T/F: The proton gradient can drive the active transport of metabolites into and out of the mitochondrion.

From the matrix to the intermembrane space

The electron transport chain pumps protons:

Oxidative Phosphorylation

The metabolic pathway in which the mitochondria in cells use their structure, enzymes, and energy released by the oxidation of nutrients to reform ATP

pumps protons across the inner mitochondrial membrane

The movement of electrons through the electron transport chain:

Ubiquione to cytochrome c.

Ubiquione has a redox potential of +30 mV, while cytochrome c. has a redox potential of +230 mV. In the electron transport chain, electrons flow from:

NADH and FADH2

What are the two things the electron transport chain accept high energy electrons from?

Pyruvate and fatty acids

What are two main fuel sources for mitochondria?

ATP synthase

What can either produce or break down ATP depending on the magnitude of the electrochemical proton gradient:

Proton gradient

What drives the production of ATP from ADP by ATP synthase?

O2

What electron acceptor allows an organism to completely break down organic molecules into CO2 and H2O and thereby release a large amount of energy that can be harnessed by the cell to do work?

Cellular respiration

What is more efficient at generating energy than a gasoline powered engine?

ATP

What is the chemical currency in cells?

High ATP/ADP ratio

What is the ratio of ATP and ADP concentrations in the cytosol of a cell?

Oxidation Reduction reaction

What kind of reaction is the electron transfer in the electron transport chain?

ATP synthase cleaves ATP to form ADP and Pi

What occurs when ATP synthase pumps H+ across a membrane against the electrochemical proton gradient?

ATP and NADPH generated in the photosynthetic light reactions

What provides the fuel to convert CO2 into sugars in chloroplasts?

Excited electrons

When a chlorophyll molecule captures light energy, what form does the energy take?

With an electron removed from water

When an electron is removed from the reaction center of photosystem II, how is the missing electron then replenished?

Reduced

When o2 accepts electrons in the electron transport chain, o2 becomes:

Produce ATP

When protons move down their electrochemical gradient into the mitochondrial matrix, they:

Highly favorable

When the difference in the redox potential between two pairs of molecules is highly positive, then the transfer of electrons is:

Photosystem I

Which photosystem is able to boost electrons to the very high energy level needed to make NADPH from NADP+?

FADH2 feeds its electrons into the electron transport chain further along the chain

Why does a single molecule of NADH result in the production of more ATP molecules than a single molecule of FADH2, via oxidative phosphorylation?