Biological Molecules - ATP, Water + Inorganic Ions

Question 1

Describe The Structure of Adenine Triphosphate (ATP)

Answer 1

Nucleotide Derivative of Adenine with 3 Phosphate Groups : Adenine-Ribose Sugar-3 Phosphate Groups

Question 2

Explain The Role of ATP in Cells

Answer 2

• Energy Released Is Coupled To Metabolic Reactions
• Phosphate Groups Phosphorylate Compounds to Make Them More Reactive
• ATP Hydrolase Catalyses ATP -> ADP+Pi

Question 3

How is ATP Resynthesised in Cells?

Answer 3

• ATP Synthase Catalyses Condensation Reaction Between ADP+Pi
• During Respiration in Cells

Question 4

Explain Why ATP is Suitable as the ‘Energy Currency’ of Cells

Answer 4

• High Energy Bonds Between Phosphate Groups
• Small Amounts of Energy Released at a Time = Less Energy Wasted as Heat
• Single-Step Hydrolysis = Quick Release Energy
• Reversible - Readily Resynthesised

Question 5

Why is Water a Polar Molecule?

Answer 5

Oxygen is More Electronegatively Charged Than Hydrogen, so Attracts Electron Density in The Covalent Bond More Strongly

Forms O- (slightly negative) AND H+ (slightly positive)

Question 6

State 4 Biologically Important Properties of Water

Answer 6

Due to Polar Charge & Intermolecular Hydrogen Bonds:

• Metabolite/Solvent For Chemical Reactions in Body
• High Specific Heat Capacity
• High Latent Heat of Vaporisation
• Cohesion Between Water Molecules

Question 7

Explain Why Water is Significant For Living Organisms

Answer 7

• Solvent For Polar Molecules During Metabolic Reactions
• Enables Organisms to Avoid Fluctuations in Core Temperature = High Specific Heat Capacity
• Cohesion and Surface Tension In Transpiration System

Question 8

What are Inorganic Ions and Where are They Found in The Body?

Answer 8

• Ions That Do Not Contain Carbon Atoms
• Found in Cytoplasm and Extracellular Fluid
• May be in High or Very Low Concentrations

Question 9

Explain The Role of Hydrogen Ions in The Body

Answer 9

• High Concentration of Hydrogen Ions = Low pH

- Hydrogen Ions Interact with Hydrogen and Ionic Bonds in Tertiary Structure of Proteins, Which Can Cause Denaturation

Question 10

Explain The Role of Iron Ions in The Body

Answer 10

• Iron Ions Bond to Porphyrin Ring to Form Haem Which is a Group In Haemoglobin
• Each Haem Group has Binding Site Used to Transport 1 Molecule of Oxygen Around Body in Bloodstream
• 4 Haem Groups Per Haemoglobin Molecule

Question 11

Explain The Role of Sodium Ions in The Body

Answer 11

• Involved in Co-Transport For Absorption of Glucose & Amino Acids in Lumen of Gut
• Involved in Propagation of Action Potentials in Neurons

Question 12

Explain The Role of Phosphate Ions in The Body

Answer 12

Component of:

• DNA
• ATP
• NADP
• cAMP