1Define chemiosmosis.
The flow of protons down an electrochemical gradient through ATP synthetase to synthesize ATP.
2State the three components of ATP.
Adenine (nitrogenous base), Ribose (pentose sugar), and three phosphate groups.
3Which enzyme hydrolyses ATP?
ATPase.
4Why is ATP called the “universal energy currency”?
It is used in all cells for all reactions in all organisms.
5What is the net yield of ATP in glycolysis?
2 ATP.
6Where is ATP synthetase located in a mitochondrion?
On the stalked particles of the inner membrane (cristae).
7What is the role of the proton pump?
To move protons from the matrix to the intermembrane space against a concentration gradient.
8What is the final electron acceptor in the ETC?
Oxygen.
9What is phosphorylation?
The addition of a phosphate group to a molecule (e.g. ADP to ATP).
10Why is ATP better than glucose as an immediate energy source?
Energy is released in small, manageable amounts so less is wasted as heat; it is a single-step hydrolysis.
11Define photophosphorylation.
The synthesis of ATP from ADP and Pi using light energy.
12Where do the protons accumulate in a chloroplast?
Inside the thylakoid space (lumen).
13What provides the energy for the electron transport chain?
High-energy electrons from reduced NAD/FAD or the photoactivation of chlorophyll.
14What is the chemical formula for the hydrolysis of ATP?
ATP + H₂O → ADP + Pi + energy.
15Is the formation of ATP a condensation or hydrolysis reaction?
Condensation reaction.
16What property allows ATP to move easily around the cell?
It is water-soluble.
17What happens to the energy gradient if oxygen is absent?
The ETC stops, no proton gradient is maintained, and ATP synthesis via chemiosmosis ceases.
18What is the function of the stalked particles?
They contain the enzyme ATP synthetase.
19How many protons are required to produce one ATP?
Three (specification dependent, usually accepted as a flow).
20What is the “Z-scheme”?
A diagram showing the pathway of electrons in non-cyclic photophosphorylation.
21Define oxidative phosphorylation.
The production of ATP via the ETC in the presence of oxygen.
22What is the importance of the cristae having a large surface area?
It provides more space for electron carriers and ATP synthetase enzymes.
23Why is ATP described as “inert”?
It does not react with other molecules unless a specific enzyme (ATPase) is present.
24What is a redox reaction?
A reaction involving both reduction (gain of electrons/hydrogen) and oxidation (loss).
25What is the role of Coenzyme A?
To carry the 2C acetyl group into the Krebs cycle.
26Define substrate-level phosphorylation.
The direct transfer of a phosphate group from a donor molecule to ADP.
27What is the byproduct of the final step of the ETC?
Water.
28Why can’t ATP be stored?
It is an immediate energy donor; cells store energy as glycogen or lipid instead.
29What causes the proton motive force?
The electrochemical gradient created by the high concentration of H⁺ ions.
30How many phosphate bonds are high energy in ATP?
Two (the bonds between the phosphate groups).