What property of water allows many biochemical reactions to occur in a liquid medium?
Water is a solvent.
Polar water molecules dissolve ions and polar molecules, enabling metabolic reactions in solution.
Which type of reaction joins two biological molecules together with the removal of a water molecule?
Condensation reaction
Forms bonds between monomers when polymers such as proteins, carbohydrates, and lipids are built.
What reaction breaks a chemical bond in a biological molecule using a molecule of water?
Hydrolysis reaction
Common in digestion and when polymers are broken into monomers.
True or False:
Water directly participates as a reactant in many metabolic reactions inside cells.
True
Water acts as a metabolite in reactions such as hydrolysis and condensation.
Water resists rapid temperature change in cells and organisms. Which property of water is responsible for this buffering effect?
High specific heat capacity
A large amount of energy is required to change the temperature of water.
True or False:
Water has a low specific heat capacity, allowing cells to heat and cool very rapidly.
False
Its relatively high specific heat capacity stabilises temperature in cells and aquatic environments.
A large amount of energy is required to convert water from liquid to vapour. What property of water does this describe?
Latent heat of vaporisation
This allows evaporation (e.g., sweating or transpiration) to remove heat efficiently.
Fill in the blank:
Evaporation of water from a surface removes heat because water has a large _______ heat of vaporisation.
latent
High energy is needed to break hydrogen bonds between water molecules.
Attraction between water molecules allows continuous columns of water to move through plant transport tissues. What property causes this attraction?
Cohesion
Hydrogen bonding between water molecules produces strong intermolecular attraction.
What property of water creates a tight surface layer where water meets air?
Surface tension
Produced by cohesive forces between water molecules at the surface.
True or False:
Cohesion between water molecules helps maintain continuous columns of water in the xylem of plants.
True
Important for maintaining the transpiration stream.
Fill in the blank:
The concentration of _______ ions affects the pH of a solution.
hydrogen
pH is determined by the concentration of hydrogen ions in a solution.
Which ion is an essential component of haemoglobin?
Iron
Fe2+ ions bind oxygen in haemoglobin molecules.
What role do sodium ions play in nutrient absorption?
Co-transport
Sodium ions help transport glucose and amino acids into cells via co-transport mechanisms.
Which ion is a structural component of both DNA and ATP?
Phosphate
Phosphate groups form the backbone of DNA and are part of ATP molecules storing energy.
True or False:
Iron ions are involved in the transport of oxygen in blood.
True
Fe2+ in haemoglobin reversibly binds oxygen for transport in red blood cells.
True or False:
Sodium ions are only used in nerve impulses, not in nutrient absorption.
False
Sodium ions are crucial for co-transport of glucose and amino acids in epithelial cells.
How do phosphate ions contribute to energy transfer?
ATP formation
Phosphate groups in ATP store and release energy when bonds are broken and reformed.
Fill in the blank:
High concentrations of _______ ions in cytoplasm can lower the pH.
hydrogen
An increase in H+ ions makes the cytoplasm more acidic.
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2: Biological Molecules119
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2: Water & Inorganic Ions19
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2: Cells52
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2: Cell Division20
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2: Membranes & Transport20
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2: Exchange Surfaces37
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2: Transport Systems39
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2: Immune system36
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2: Enzymes & Digestion16
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3: Plant Transport20
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4: Biodiversity & Classification32
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4: Investigating Diversity12
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4: Evolution42
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4: Disease24
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5: Photosynthesis23
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5: Respiration17
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5: Energy & Ecosystems35
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5: Homeostasis57
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5: Nervous & Hormonal Communication115
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5: Muscles14
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6: DNA & Protein Synthesis27
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6: Meiosis & Genetic Diversity14
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6: Inheritance12
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6: Populations (Hardy–Weinberg)15
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6: Ecosystems & Population Dynamics24
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6: Gene Mutations & Expression58
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6: Biotechnology & Genomics46
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6: ATP & Energy Transfer (Integration)11
