5.7.1: The need for cellular respiration Flashcards
What is respiration?
- The process that occurs in living cells and releases the energy stored in organic molecules such as glucose.
- The energy is immediately used to synthesise molecules of ATP from ADP and inorganic phosphate (Pi).
- ATP in cells can be hydrolysed to release energy needed to drive biological processes.
What is energy?
-Energy is the capacity to do work.
What type of energy do molecules - e.g. fats, carbohydrates and proteins contain?
- potential energy.
- Also chemical energy converted from light energy during the process of photosynthesis.
When this energy is released from organic molecules, via respiration, it can be used to make ATP to drive biological processes. Give examples.
- Active transport
- Endocytosis
- Exocytosis, including secretion of large molecules from cells.
- Synthesis of large molecules such as proteins e.g. collagen, enzymes and antibodies.
- DNA replication.
- Cell division
- Movement (bacterial flagella, eukaryotic cilia and undulipodia, motor proteins)
- Activation of chemicals (glucose phosphorylated to become moe reactive)
What are all of the chemical reactions that take place within living cells known collectively as?
Metabolism or metabolic reactions.
What are anabolic reactions?
Metabolic reactions where large molecules are synthesised from smaller molecules.
What are catabolic reactions?
Metabolic reactions involving the hydrolysis of large molecules to smaller ones.
In cells, what allows atoms and molecules to move?
Kinetic energy
Describe the structure of ATP.
- A phosphorylated nucleotide.
- Each molecule of ATP consists of…
- adenosine, which is the nitrogenous base adenine plus the 5 carbon sugar, ribose,
- three phosphate (phosphoryl groups).
When is ATP stable and when is it not stable?
ATP is relatively stable (it does not break down into ADP and Pi) when in solution in cells. However, whilst in solution, it can easily be moved from place to place within a cell
How is ATP is the intermediate energy source for metabolic reactions?
The energy-releasing hydrolysis is coupled with an energy-consuming metabolic reaction.
How does ATP allow cells to obtain the energy they need for a process in small manageable amounts that will not cause damage or be wasteful?
When ATP is hydrolysed to ADP and Pi, a small amount of energy is released for use within the cells.
Why is ATP referred to as the universal energy currency?
It occurs in all living cells and is a source of energy that can be used by cells in small amounts.
What is some of the energy from ATP released as and is this wasteful?
Heat.
- Not inefficient or wasteful
- Heat helps keep living organisms ‘warm’
- Enables their enzyme-catalysed reactions to proceed at optimum temperature.
