1.6.1
Structure of ATP
Structure and Function of ATP
Structure and Function of ATP
ATP is called a nucleotide derivative because it is a modified form of a nucleotide.
Components of ATP
Components of ATP
- The components of ATP are:
- Adenine - a nitrogenous base.
- Ribose - a five-carbon sugar.
- Three phosphate groups.
Function of ATP
Function of ATP
- ATP is a small, relatively simple molecule.
- This molecule can be thought of as the primary energy currency of cells.
- ATP is the cell's equivalent of money, which people exchange for things they need.
- ATP is used to power most energy-requiring cellular reactions.
Hydrolysis of ATP
Hydrolysis of ATP
Hydrolysis of ATP happens when a cell needs energy.
ATP hydrolysis reaction
ATP hydrolysis reaction
- The equation for the hydrolysis of ATP is:
- ATP + H2O → ADP + Pi (+ energy)
- Hydrolysis of ATP to adenosine diphosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme ATP hydrolase.
- This reaction uses a water molecule so is called a hydrolysis reaction.
Energy release
Energy release
- Energy is released during the hydrolysis of ATP as one of the phosphate bonds is broken.
- This energy is used to perform work inside the cell.
Energy coupling
Energy coupling
- The hydrolysis of ATP can be coupled to other reactions within cells that need energy.
- An example of energy coupling using ATP is the transmembrane sodium-potassium pump (Na+/K+ pump):
- Energy is released from the hydrolysis of ATP.
- Energy is needed to power the pump that drives Na+ out of the cell and K+ into the cell.
Phosphorylation
Phosphorylation
- The inorganic phosphate released in ATP hydrolysis can be used to phosphorylate other compounds.
- This often makes the compounds more reactive.
Resynthesis of ATP
Resynthesis of ATP
Like most chemical reactions, the hydrolysis of ATP to ADP is reversible.
ATP resynthesis reaction
ATP resynthesis reaction
- The equation for the resynthesis of ATP is:
- ADP + Pi (+ energy) → ATP + H2O
- ATP is resynthesised by the condensation of ADP and an inorganic phosphate.
- This reaction is catalysed by the enzyme ATP synthase during photosynthesis or respiration.
Formation of ATP requires energy
Formation of ATP requires energy
- Cells rely on the regeneration of ATP just as people rely on the regeneration of spent money through some sort of income.
- Since ATP hydrolysis releases energy, ATP regeneration must require an input of energy (just like earning money requires hard work!).
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
Jump to other topics
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
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