Questions and Answers
Which characteristic of living organisms allows them to extract and use energy from their environment?
What is one of the molecules in living organisms that behaves in accordance with physical and chemical laws?
What is meant by the term 'Molecular Logic of Life'?
Why is water considered a main constituent of all known living organisms?
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Which of the following best describes the structural attributes of living matter?
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What property of water makes it vital for life, aside from providing calories or nutrients?
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Which of the following statements about non-covalent interactions is true?
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How do living organisms achieve self-replication and self-assembly?
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Which interaction is primarily responsible for the structure of membranes and the stability of proteins?
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What is the significance of hydrogen bonds in water's properties?
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How does water function as a universal solvent?
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What is water's heat capacity?
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What role do electrostatic interactions play in biomolecules?
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What is the bond angle in a water molecule?
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Why are non-polar molecules not soluble in water?
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What does the heat of vaporization in water refer to?
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In which scenarios are dipole-dipole interactions most significant?
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Which aspect describes the polar nature of water?
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What is the primary purpose of buffers in biological systems?
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Which of the following components are part of the bicarbonate buffer system?
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What happens to the bicarbonate concentration when excess HCO3- is produced?
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How does H2CO3 contribute to pH regulation in the body?
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What is the normal pH of intracellular fluids, which the phosphate buffer system helps to maintain?
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Which protein is noted for its significant buffering capacity in blood?
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What role does the concentration of H+ ions play in living organisms?
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What defines a buffer in biological systems?
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Study Notes
Properties and Structure of Water
- Water is the most abundant compound in living organisms, comprising about 70% of their weight.
- Acts as a medium for nutrient transport, enzyme reactions, and chemical energy transfer.
- Properties include:
- Density: 997 kg/m³
- Boiling point: 100 °C
- Melting point: 0 °C
- Molar mass: 18.01528 g/mol
- IUPAC ID: Oxidane, Water
- Structure consists of two hydrogen atoms covalently bonded to one oxygen atom, forming a polar molecule.
- Bond angle in a water molecule is 104.5°.
Thermal Properties of Water
- Effective modulator of climatic temperatures, capable of absorbing and releasing solar heat gradually.
- High heat capacity aids in maintaining internal temperatures in organisms.
- Evaporation serves as a cooling mechanism, with an adult human losing up to 1200g of water daily through expiration, sweat, and urine.
- Heat loss during evaporation can account for approximately 20% of total metabolic heat generation.
Solvent Properties of Water
- Water's dipolar nature enables it to dissolve many ionic and polar substances, earning it the title of "universal solvent."
- Non-polar molecules do not dissolve in water due to the absence of polar functional groups and H-bond formation.
- Water's high dielectric constant facilitates dissolving ionic substances by reducing the attractive forces between ions.
Non-Covalent Bonding
Hydrogen Bonds
- Electrostatic interactions between hydrogen atoms of one water molecule and oxygen of another form hydrogen bonds.
- Weaker than ionic and covalent bonds but provide cohesion, making liquid water stable at room temperature.
- Hydrogen bonding influences the structure and function of biomolecules.
Electrostatic Interactions
- Occur between oppositely charged atoms/groups, crucial for the shape and function of biomolecules (e.g., protein structures).
- Water molecules attract charged ions, promoting hydration which facilitates ion solubility.
Hydrophobic Interactions
- Non-polar molecules minimize their contact with water, leading to molecular aggregation and stability in structures like membranes and proteins.
Other Non-Covalent Interactions
- Include dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole interactions.
Bonding Properties of Carbon
- Carbon can form tetrahedral structures, leading to isomerism, including cis-trans isomerism due to restricted rotation.
- Carbon forms four covalent bonds, allowing for diverse organic compounds, especially hydrocarbons.
Buffers in Living Organisms
- Buffers maintain constant hydrogen ion concentration in biological systems.
- A buffer usually consists of a weak acid and its conjugate base, regulating pH essential for cellular processes.
Physiological Buffers
- Bicarbonate Buffer: Significant in blood regulation. CO2 and H2O components convert to carbonic acid, which dissociates to maintain pH balance.
- Phosphate Buffer: Important in intracellular fluids, consisting of H2PO4- and HPO4-2, critical for maintaining cellular pH.
- Protein Buffer: Composed of amino acids; hemoglobin plays a vital role in blood pH maintenance.
The Cell and Biochemistry
- Cells are structural and functional units of life, analyzing biochemical processes vital for understanding living systems.
- Biochemistry is defined as the chemistry of living organisms, focusing on the interaction of lifeless molecules that support life.
- Living matter is structurally complex, organized, and uniquely interacts under a "Molecular Logic of Life."
- The primary goal of biochemistry is to understand how biomolecules interact to sustain life.
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Description
Explore the vital role of water in living organisms through this quiz. Learn about its properties, significance, and how it facilitates essential biological processes. Test your knowledge on the characteristics and functions of water in life forms.