5A - Photosynthesis, respiration and ATP Flashcards
What do plants need energy for?
Photosynthesis, active transport, DNA replication, cell division and protein synthesis.
What do animals need energy for?
Muscle contraction, maintenance of body temperature, active transport, DNA replication, cell division and protein synthesis.
Why do plant and animal cells need energy?
For biological processes to occur.
In what form does photosynthesis store energy?
In glucose.
What is photosynthesis?
The process where energy from light is used to make glucose from water and carbon dioxide.
What is light energy converted into in photosynthesis?
Chemical energy in the form of glucose.
Is photosynthesis one or many reactions?
It occurs in a series of reactions.
What is the equation for photosynthesis?
6CO2 + 6H2O (+energy) –> C6H12O6 (glucose) + 6O2
When is the energy in plants no longer stored as glucose?
When it is released by respiration.
How do animals obtain glucose?
By eating plants (or other animals).
How is glucose released in animals?
It is respired to release energy.
How do cells release energy from glucose?
By respiration.
What process releases energy from glucose?
Respiration.
How many types of respiration are there?
2
What are the 2 types of respiration?
Aerobic and anaerobic.
What is aerobic respiration?
Respiration using oxygen.
What is anaerobic respiration?
Respiration without oxygen.
What does aerobic respiration produce?
CO2 and water, and it releases energy.
What is the equation for aerobic respiration?
C6H12O6 (glucose) + 6O2 –> 6CO2 + 6H2O (+ energy)
What does anaerobic respiration in plants and yeast produce?
Ethanol and CO2, and releases energy.
What does anaerobic respiration in humans produce?
Lactate, and releases energy.
What is the immediate source of energy in a cell?
ATP
What is ATP made from?
From the energy released from glucose.
What does ATP stand for?
Adenosine triphosphate.
What does ATP do?
The immediate source of energy in a cell - it carries energy around the cell to where it is needed.
How is ATP synthesised?
Via a condensation reaction between ADP and an inorganic phosphate using energy from an energy-releasing reaction.
What does ADP stand for?
Adenosine diphosphate.
Where is energy stored in ATP?
As chemical energy in the phosphate bonds.
How does ATP get to the part of the cell it is needed in?
By diffusion.
What does ATP synthase do?
Catalyses the condensation reaction of ADP and Pi back into ATP.
What happens to ATP when it reaches the part of the cell where it is needed?
It is hydrolysed back into ADP and Pi. Chemical energy is released from the phosphate bond and used by the cell.
What does ATP hydrolase do?
Catalyses the hydrolysis reaction of ATP into ADP and Pi.
What happens after ATP is hydrolysed back into ADP and Pi after reaching the part of the cell where it is needed?
The ADP and Pi are recycled and the process starts again.
What does Pi stand for?
Inorganic phosphate.
What specific properties of ATP make it a good energy source?
- ATP stores or releases only a small, manageable amount of energy at a time, so no energy is wasted as heat.
- It’s small and soluble so can be easily transported around the cell.
- It’s easily broken down, so energy can be released instantaneously.
- It can be remade quickly.
- It can make other molecules more reactive by transferring one of its phosphate groups to them (phosphorylation).
- ATP can’t pass out of the cell, so the cell always has an immediate supply of energy.
What is a metabolic pathway?
A series of small reactions controlled by enzymes, e.g. respiration and photosynthesis.
What is phosphorylation?
Adding phosphate to a molecule, e.g. ADP is phosphorylated to ATP.
What is photophosphorylation?
Adding phosphate to a molecule using light.
What is photolysis?
The splitting (lysis) of a molecule using light (photo) energy.
What is photoionisation?
When light energy ‘excites’ electrons in an atom or molecule, giving them more energy and causing them to be released. The release of electrons causes the atom or molecule to become a positively charged ion.
What is hydrolysis?
The splitting (lysis) of a molecule using water (hydro).
What is decarboxylation?
The removal of carbon dioxide from a molecule.
What is dehydrogenation?
The removal of hydrogen from a molecule.
What are redox reactions?
Reactions that involve oxidation and reduction.
What is reduction?
When something has gained electrons and may have gained hydrogen or lost oxygen.
What is oxidation?
When something has lost electrons and may have lost hydrogen or gained oxygen.
What do photosynthesis and respiration involve the use of?
Coenzymes.
What are coenzymes?
Molecules that aid the function of an enzyme.
How do coenzymes work?
By transferring a chemical group from one molecule to another.
What coenzyme is used in photosynthesis?
NADP
How does the coenzyme NADP work in photosynthesis?
It transfers hydrogen from one molecule to another meaning it can reduce (give hydrogen to) or oxidise (take hydrogen from) a molecule.
What are examples of coenzymes that are used in respiration?
NAD, coenzyme A and FAD.
What do the coenzymes NAD and FAD do in respiration?
Transfer hydrogen from one molecule to another meaning it can reduce (give hydrogen to) or oxidise (take hydrogen from) a molecule.
What does the coenzyme ‘coenzyme A’ do in respiration?
Transfers acetate between molecules.
What happens when hydrogen is transferred between molecules?
Electrons are transferred too.
