Podcast Beta
Questions and Answers
What is the primary respiratory substrate used in cellular respiration?
All the energy from respiratory substrates is released at once during cellular respiration.
False
What acts as the energy currency of the cell?
ATP
The sequence of use of respiratory substrates is carbohydrates, _____, and proteins.
Signup and view all the answers
Match the following respiratory substrates with their calorific values:
Signup and view all the answers
Which of the following statements accurately describes cellular respiration?
Signup and view all the answers
Plants have specialized organs for gas exchange.
Signup and view all the answers
What are the alternatives to carbohydrates that can be used as respiratory substrates?
Signup and view all the answers
What type of respiration occurs when carbohydrates or fats are oxidized inside the cell?
Signup and view all the answers
Plants require large volumes of gases for respiration during photosynthesis.
Signup and view all the answers
What is the primary end product of aerobic respiration?
Signup and view all the answers
Plants utilize __________ respiration when no oxygen is present.
Signup and view all the answers
Match the type of respiration with its key characteristic:
Signup and view all the answers
How many molecules of ATP are gained from anaerobic respiration for each molecule of glucose?
Signup and view all the answers
During aerobic respiration, oxygen acts as the final hydrogen acceptor.
Signup and view all the answers
Name an example of a substance that can act as a hydrogen acceptor during alcoholic fermentation.
Signup and view all the answers
Study Notes
Cellular Respiration
- Oxidation of C–C single bonds in complex compounds releases energy and synthesizes ATP.
- Energy is released gradually through a series of enzyme-controlled reactions to prevent excessive heat generation.
- ATP serves as the energy currency of the cell, breaking down when energy is needed.
- Respiratory substrates primarily include carbohydrates (mainly glucose), fats, proteins, and organic acids.
- Gross calorific values:
- Carbohydrates: 4.1 kcal/g
- Proteins: 5.65 kcal/g
- Fats: 9.45 kcal/g
- Physiological values:
- Carbohydrates: 4.0 kcal/g
- Proteins: 4.0 kcal/g
- Fats: 9.0 kcal/g
- Sequence of use for respiratory substrates: carbohydrates → fats → proteins.
- Organic acids, such as malic acid, can also serve as respiratory substrates under specific conditions.
Features of Cellular Respiration
- Cellular respiration is an amphibolic process, producing carbon skeletons used for synthesizing other molecules.
- It is an exergonic process, as it releases significant energy from breaking C–C bonds.
Respiration in Plants
- Plants lack specialized organs for gas exchange, relying on stomata and lenticels.
- Each plant part manages its gas exchange, resulting in minimal gas transport needs.
- Gas exchange demands in plants are low compared to animals.
- While photosynthesis occurs, O2 is released, alleviating O2 availability issues for cells.
- Gas diffusion distances are short within the plant, facilitating access to air by most cells.
- Parenchyma cells create air spaces that further enhance gas exchange.
Types of Respiration
Based on Respiratory Substrates
- Floating Respiration: Involves oxidation of carbohydrates or fats, utilizing these substrates stored within the cell.
- Protoplasmic Respiration: Involves oxidation of proteins, occurring in starved cells as proteins are constituents of protoplasm.
Based on Presence of Oxygen
-
Aerobic Respiration:
- Complete oxidation of glucose yielding CO2 and H2O.
- Intermolecular respiration with a yield of 36 or 38 ATP molecules per glucose.
- NADH is oxidized vigorously to NAD+; O2 serves as the final hydrogen acceptor.
- Reaction: C6H12O6 + 6O2 → 6CO2 + 12H2O + 686 kcal.
-
Anaerobic Respiration/Fermentation:
- Partial breakdown of glucose producing lactic acid or ethanol and CO2.
- Intramolecular respiration with a yield of only 2 ATP molecules per glucose.
- NADH oxidation occurs slowly; hydrogen acceptors include acetaldehyde (alcoholic fermentation) or pyruvate (lactic acid fermentation).
- Reaction: C6H12O6 → 2CH3CH2OH + 2CO2 + less than 7% of energy of glucose.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz delves into the intricate process of cellular respiration, highlighting the oxidation of various substrates and the generation of ATP. It explores energy release, the efficiency of different respiratory substrates, and the significance of cellular respiration in metabolism.
