Practice Question For Chap 6 & Chap 7 Flashcards
When is oxygen used in cellular respiration?
As the final electron acceptor in the electron transport chain.
What happens to pyruvate after glycolysis in the absence of oxygen?
It undergoes fermentation to produce either lactic or ethanol
What are the two main types of fermentation, and what are their end products?
Alcohol fermentation (ethanol) and lactic acid fermentation (lactic acid)
Which stage of cellular respiration directly requires oxygen?
Electron transport chain
How does the formation of a proton gradient drive ATP production in the mitochondria?
Protons move down their concentration gradient through ATP synthase, which powers the synthesis of ATP
What is the total ATP yield from glycolysis per one molecule of glucose?
2 ATP
What is the role of oxygen in the electron transport chain?
To accept electrons and combine with protons a to form water
Which of the following reactions is Endergonic?
ATP synthesis from ADP and Pi
(inorganic phosphate)
How many ATP molecules are generated per glucose molecule in the electron transport chain(oxidative phosphorylation).
28-30 ATP
What goes into glycolysis, and what come out?
In: 1 glucose, 2 NAD+, 4 ADP + P (phosphate group)
Out: 2 pyruvate, 2 NADH, 4 ATP
(net 2 ATP)
ATP is formed glycolysis by substrate-level phosphorylation.
What enters pyruvate oxidation, and what is produced?
In: 2 pyruvate, 2 NAD+, 2 CoA (coenzyme A)
Pyruvate enters a series of redox reactions
Out: 2 acetyl-CoA, 2 NADH, 2 CO2
What enters the citric acid cycle, and what comes out?
In: 2 acetyl-CoA, 6 NAD+, 2 FAD, 2 ADP + P
Out: 4 CO2, 6 NADH, 2 FADH2, 2 ATP or ( GTP)
What goes into the electron transport chain, and what comes out?
In: 10 NADH, 2 FADH2, O2, ADP + P
Out: 28-30 ATP, H2O, NAD+, FAD
What is required for ATP synthesis via oxidative phosphorylation, and what are the products?
In: ADP + P , H+ gradient (proton gradient), O2
Out: ATP, H2O
What goes into lactic acid fermentation, and what comes out?
In: 2 pyruvat, 2 NADH
Out: 2 lactate, 2 NAD+
What goes into alcohol fermentation, and what is produced?
In: 2 pyruvate, 2 NADH
Out: 2 ethanol, 2 CO2, 2 NAD+
What enters the light reactions of photosynthesis, and what come out?
In: light energy, H2O, NADP+, ADP + P
Out: O2, ATP, NADPH
What goes into the Calvin cycle (dark reactions) and what comes out?
In: CO2, ATP, NADPH
Out: G3P ( a 3- carbon sugar), ADP+ P, NADP+
What are the inputs and outputs of the entire cellular respiration process (combining stages)?
In: 1 glucose, 6 CO2
Out: 6 CO2, 6 H2O, - 32-34 ATP
True/False
Glycolysis occurs in the mitochondria of eukaryotic cells.
False (glycolysis occurs in the cytoplasm )
True/False
In the absence of oxygen, cells can undergo fermentation to produce ATP.
True
Pyruvate must be converted into acetyl-CoA before it can enter the citric acid cycle.
True
True/False
Oxygen is used directly during glycolysis to break down glucose.
False (Oxygen is not required in glycolysis; it is used in the electron transport chain.)
True/False
The electron transport chain creates a proton gradient across the mitochondrial membrane, which drives ATP production.
True
True/False
Fermentation produces more ATP than aerobic respiration
False
(Fermentation produces far less ATP than aerobic respiration, which can yield around 32-34 ATP per glucose molecule).
True/False
Carbon dioxide is produced during both pyruvate oxidation and the citric acid cycle
True
True/False
The total ATP yield from glycolysis is 4 ATP, but the net gain is 2 ATP.
True
True/False
The final electron acceptor in the electron transport chain is oxygen, which forms water
True
True/False
The citric acid cycle directly uses oxygen to oxidize acetyl-CoA
False
( the citric acid cycle does not use oxygen directly; oxygen is only involved at the electron transport chain)
What are the three main stages of cellular respiration, and where do they occur in eukaryotic cells?
- Glycolysis: occurs in the cytoplasm
- Pyruvate oxidation and the citric acid cycle: occurs in the mitochondrial matrix
- Oxidative phosphorylation (electron transport chain and Chemiosmosis): occurs in the inner mitochondrial membrane
What is the primary purpose of glycolysis, and what are the main products?
The purpose of glycolysis is to break down glucose ( 6- carbon molecule) into two molecules of pyruvate (3-carbon molecules). The main products are:
- 2 ATP (net gain)
- 2 NADH
- 2 pyruvate
During pyruvate oxidation, what happens to pyruvate before it enters the citric acid cycle?
Pyruvate is converted into acetyl-CoA. This process involves the removal of one carbon (released as CO2), reduction of NAD+ to NADH, and the addition of coenzyme A to form acetyl-CoA.
What goes into the citric acid cycle, and what comes out?
In;
- 2 acetyl-CoA
- 6 NAD+
- 2 FAD
- 2 ADP + P
Out;
- 4 CO2
- 6 NADH
- 2 FADH2
- 2 ATP
Explain the role of the electron transport chain (ETC) in oxidative phosphorylation.
The electron transport chain ETC consists of protein complexes embedded in the inner mitochondrial membrane. Electrons from NADH and FADH2 are transferred through these complexes, releasing energy. Thus energy is used to pump protons (H+) from the mitochondrial matrix into the Intermembrane space, creating a proton gradient.
What is Chemiosmosis, and how does it contribute to ATP production?
Chemiosmosis is the process by which protons flow down their concentration gradient from the Intermembrane space back into the mitochondrial matrix through the enzyme ATP synthase. This flow of protons drives the production of ATP from ADP and inorganic phosphate.
