Unit 3 Biology Grade 10 Teacher John 12/31/2024 PDF

Unit 3: Biochemical molecules Content 3.1. Biochemical Learning objectives molecules 3.1.1.  Identify inorganic and organic biochemical molecules Inorganic molecules:  Explain the properties of water and its importance for life water...

Unit 3: Biochemical molecules Content 3.1. Biochemical Learning objectives molecules 3.1.1.  Identify inorganic and organic biochemical molecules Inorganic molecules:  Explain the properties of water and its importance for life water  Discuss different inorganic ions and their contribution to the cell 3.1.2. Inorganic ions  Classify organic molecules based on their constituent  elements and the monomers from which they are 3.1.3. Organic constructed.  Discuss the role of biological molecules in the cell molecules structure  Elaborate the functions of carbohydrates, proteins, Carbohydrates lipids, and Nucleic acids to the body.  Conduct experiments to identify nutrients in different Lipids foodstuff   3.1. Biochemical Molecules OBJECTIVES:- ! AT THE END OF THIS SECTION, THE STUDENT WILL BE ABLE TO: ! IDENTIFY INORGANIC AND ORGANIC BIOCHEMICAL MOLECULES, ! DISCUSS DIFFERENT INORGANIC IONS AND THEIR CONTRIBUTION TO THE CELL ! EXPLAIN THE PROPERTIES OF WATER AND ITS IMPORTANCE FOR LIFE. What are biological molecules, and how would  Biomolecule you define them? Definition  A biomolecule refers to any molecule that is produced by living organisms. As such, most of them are organic molecules. The four major groups of biomolecules include polysaccharides, proteins, nucleic acids (DNA and RNA), and lipids. They are found in and produced by living organisms. Thus, many of the biomolecules are polymers. A polymer is a compound made up of several repeating units (monomers) or protomers and produced by polymerization.  Most of these biomolecules are organic compounds. Being “organic” means, in general, they contain carbon atoms covalently bound to other atoms, especially Carbon-Carbon (C-C) and Carbon-Hydrogen (C-H). The four major element constituents are carbon, hydrogen, oxygen, and nitrogen.  Etymology between H and O is unequal; the electrons are more often in the vicinity of the oxygen atom than hydrogen.  Thisunequal electron sharing creates two electric dipoles in the water molecule with oxygen-bearing a partial negative charge and hydrogen bearing a partial positive charge. This makes water a polar molecule The polarity of water has important chemical implications conferring its typical properties. Another important consequence of the polarity of the water molecule is that water molecules attract 3.1.1 Inorganic Molecule: Water Understanding the Significance of Water in Living Systems yohanees m. 12/31/2024  Introduction to Inorganic Molecules Inorganic molecules do not contain carbon and are not created through biological means (with exceptions for carbon oxides and carbonates). importances of inorganic Molecules Certain inorganic molecules are crucial for the survival of living organisms.  Chemical Composition: Water as an Inorganic Molecule water (H₂O) is composed of two hydrogen atoms and one oxygen atom.  Role in Life: Essential for life; constitutes 70-95% of cell mass and around 60% of human body mass.  Properties of Water Simple Yet Complex: Despite its simplicity, water has unique properties.  Molecular Structure: Each hydrogen atom shares an electron pair with the oxygen atom. Polarity: Water is a polar molecule due to unequal electron sharing. Polarity and Electric Dipoles  Dipoles: Oxygen bears a partial negative charge, while hydrogen bears a partial positive charge.  Implications: This polarity leads to significant chemical properties.  Hydrogen Bonding Hydrogen Bonds: Interaction between partially charged atoms in water molecules. Network Formation: The hydrogen bond network is crucial for many of water's unique properties.  Unique Properties of Water  High Specific Heat: Water can absorb a lot of heat without a significant increase in temperature.  Cohesion and Adhesion: Water molecules stick to each other (cohesion) and to other substances (adhesion).  Solvent Properties: Water is known as the "universal solvent," facilitating chemical reactions in biological systems. Typical Properties of Water - Solvent Properties  Water as a Solvent Water molecules attract ions (e.g., Na⁺, Cl⁻) and polar molecules (e.g., sugars, glycerol).  This attraction causes these molecules to dissolve by congregating and separating in water.  Polar Molecules:  Unequal charge distribution allows interaction with water. Insolubility of Non-Polar Molecules: Non-polar molecules (e.g., lipids) do not dissolve in water. Water's cohesive nature pushes non-polar molecules together when surrounded by water.  Importance of Hydrogen  CohesionBonds in Water: : Hydrogen bonds allow water molecules to stick to each other, which is why water has high surface tension. This property is important for processes like water transport in plants.  Adhesion: Water molecules can also adhere to other polar surfaces, which helps in capillary action (the ability of water to flow in narrow spaces).  High Specific Heat: Hydrogen bonds require a significant amount of energy to break, which gives water a high specific heat capacity. This means water can absorb a lot of heat without a significant change in temperature, helping to regulate climate and maintain stable temperatures in organisms.  Density and Ice Formation: When water freezes, hydrogen  High Specific Heat Capacity of 1. Water Heat capacity is the amount of heat required to raise the temperature of a substance by a specific amount.  Specific Heat Capacity of Water: The energy needed to raise the temperature of 1 kg of water by 1°C. 2.Molecular Movement:  To increase the temperature of a liquid, its molecules must gain energy and move more quickly.  Water molecules are held together by hydrogen bonds, which restrict their movement.  3. Role of Hydrogen Bonds:  Hydrogenbonds must be broken for water molecules to move freely, requiring more energy to raise the temperature.  This results in water having a higher heat capacity compared to substances without hydrogen bonding.  Biological Significance  Water’s high specific heat capacity allows it to absorb and store large amounts of heat energy.  This property makes water resistant to temperature changes, providing a stable environment for aquatic life and regulating climate. 3. High Latent Heat of Vaporization  The energy required to convert a liquid into a gas. Water's High Latent Heat:  Water has a high latent heat of vaporization due to strong hydrogen bonds.  Significant energy is needed to break these bonds for vaporization to occur.  Density and Freezing Properties  Unique Density Behavior: Ice is less dense than liquid water, allowing it to float. Temperature Effects: Water density decreases below 4°C.  Ice insulates water below, preventing complete freezing and supporting aquatic life.  Nutrient Circulation: Changes in density create currents that help circulate nutrients in oceans.  High Surface Tension and  Cohesion: Water Cohesion molecules stick together due to strong cohesive forces.  Adhesion: Water molecules also adhere to other surfaces, often stronger than cohesion.  CapillaryAction: Water climbs in narrow tubes (capillary action) due to adhesion to surfaces (e.g., glass).  Importance in Plants: Cohesive and adhesive forces are essential for water transport from roots to leaves.  Boiling and Freezing Points of Water Hydrogen Bonds: Water molecules form hydrogen bonds, affecting its properties High Boiling Point: Water boils at 100°C, despite its low molecular weight. More energy is needed to break hydrogen bonds before boiling occurs. Freezing Point: Water freezes at 0°C; similar energy considerations apply.  Importance for Ecosystems:  Stable boiling and freezing points prevent drastic environmental changes in bodies of water (oceans, lakes).  Protects aquatic life from extreme temperature fluctuations. Cooling Mechanism: Water's properties help regulate body temperature through sweating.  Comparison: Water differs from most compounds in its boiling and freezing behavior.  3.1.2. Inorganic Ions  Charged entities formed by atoms with unshared electrons in their outer shell. Can be positively (cations) or negatively (anions) charged.  Associations: Often found paired with oppositely charged ions.  Forms in Living Organisms: Free: Dissolved in cytoplasm. Bound: Associated with complex organic substances. Functions: Participate in critical biological functions. Essential for various physiological processes. Importance: Found in trace amounts, but vital for health. Changes in their concentrations can lead to serious health issues. Commonly Known As: Often referred to as minerals in the context of human health.  Classification of inorganic ions Based on their requirement in the daily diet of a normal individual, inorganic ions or minerals in the human body are divided into two categories; Macro-nutrients & Micro-nutrients  A. Hydrogen Ions  Hydrogen ions (H⁺) are crucial for maintaining balance and equilibrium in living systems. They are released during metabolic processes and are present in various body fluids, including cytoplasm, blood, and cerebrospinal fluid (CSF). Importance:  pH Regulation: The concentration of hydrogen ions is measured as pH, which ranges from 1 to 14.  Inverse Relationship: Higher pH values indicate lower concentrations of hydrogen ions and vice versa. This balance is vital for cellular functions and overall homeostasis.  B. Sodium Ions  Sodium ions (Na⁺) are the second most important positively charged ions in the body, primarily found in extracellular fluids at higher concentrations than in the cytoplasm of cells.  Importance:  Essential Nutrient: Sodium is crucial for normal body function and must be consumed daily, with the average requirement being 3 to 6 grams.  Source: Commonly obtained from dietary salt.  Excess Intake: Most people consume more sodium than needed, and excess is eliminated through urine.  Blood Pressure Regulation: Individuals with high blood  C. Potassium Ions Potassium ions (K⁺) are essential electrolytes that must be consumed daily, with an average requirement of 3 to 4 grams for a healthy adult.  Sources:  Dietary Sources: Abundant in fruits (e.g., bananas, oranges), vegetables (e.g., potatoes), and meats (e.g., chicken, liver).  Importance:  Cell Function: Potassium is crucial for the normal functioning of cells, nerves, and muscles.  Intracellular Concentration: It is the major intracellular cation, primarily found within cells, helping to maintain a stable potassium level in the blood.  D. Calcium Ions  Calcium ions (Ca²⁺) are the most abundant inorganic ions in the body, primarily found in the cytoplasm of cells and in bones and teeth.  Sources:  DietarySources: Ideal sources include milk and dairy products, as well as leafy vegetables, egg yolk, fish, and beans.  Importance:  Body Composition: Calcium constitutes about 1 to 1.5 kg of body weight, with 99% stored in bones and teeth.  Cellular Functions: The remaining 1% in the cytoplasm and  E. Phosphate Ions  Phosphate ions (PO₄³⁻) are negatively charged inorganic ions that play a vital role in the body, with an average adult containing around 1 kg of phosphate.  Sources:  Dietary Sources: Rich sources include milk, cereals, meat, and eggs.  Importance:  Bone Health: Most phosphate ions are found combined with calcium in bones and teeth, contributing to structural integrity.  Daily Requirement: An adult male needs approximately 800 mg of phosphate ions daily, similar to calcium requirements.  How much does our body Requires phosphate Ions ?  Phosphate Ions: Body Requirement and Sources  Daily Requirement: An adult male needs approximately 800 mg of phosphate ions per day.  Dietary Sources: Phosphate ions can be obtained from:  Milk and Dairy Products  Cereals  Meat  Eggs  F. Chloride Ions Chloride ions (Cl⁻) are negatively charged inorganic ions primarily found in extracellular fluids. Importance:  Concentration: The concentration of chloride ions in the body is similar to that of sodium ions, which are the major extracellular cations.  ElectrolyteBalance: Chloride plays a critical role in maintaining osmotic pressure and fluid balance in the body.  Acid-Base Balance: It contributes to the regulation of acid-base balance and is involved in the formation of  Daily Requirement and Functions of chloride Ions The average daily requirement for chloride ions is 5 to 10 grams.  Sources: Chloride is typically consumed in the form of sodium chloride (NaCl), commonly known as table salt, found in cooked food.  Functions: Osmotic Pressure & Fluid Balance: Chloride ions, in combination with sodium ions, help maintain osmotic pressure and fluid balance in the body.  Acid-Base Balance: They play a role in regulating acid-base balance.  Hydrochloric Acid Production: Chloride is essential for the  G. Iron Ions Iron ions (Fe²⁺/Fe³⁺) are positively charged ions essential for various bodily functions.  Sources: Rich dietary sources include: Legumes (e.g., beans) , Red meat,Liver, Spinach, Pumpkin seeds, Fish  Importance of Iron Ions  Oxygen Transport: Iron is a critical component of hemoglobin and myoglobin, which are necessary for the transport of oxygen and carbon dioxide in the body.  Energy Production: It is an essential element in cytochromes, which are involved in the electron transport chain, crucial for cellular respiration and Clinical Conditions Related to Iron Metabolism 1. Iron-Deficiency Anemia:  A common condition resulting from inadequate iron intake, leading to reduced hemoglobin levels and impaired oxygen transport. 2. Hemosiderosis: Characterized by excess iron accumulation in the body, often due to repeated blood transfusions or excessive dietary iron. 3. Hemochromatosis:  A genetic condition that causes abnormal iron deposits in organs such as the liver, spleen, skin, and pancreas, potentially leading to organ damage.  H. Copper Ions  Copper ions (Cu²⁺) are positively charged inorganic ions that play essential roles in various biological processes within the body. Sources: Dietary sources of copper include: Shellfish,.Seeds and nuts.Organ meats,Wheat and whole grains,ChocolateImportance of Copper Ions Enzyme Function:  Copper is an essential component of several important  Synthesis of Key  Copper ions are necessary for the synthesis of: Hemoglobin Biomolecules: (for oxygen transport), Collagen (for connective tissue strength) , Elastin (for skin and tissue elasticity) Nervous System Development:  Copper is crucial for the normal development and functioning of the nervous system. Clinical Condition Related to Copper Metabolism Wilson Disease: A rare genetic disorder characterized by abnormal copper  Iodine Ions Iodine ions (I⁻) are essential trace minerals found naturally in the earth's soil and ocean waters, playing a crucial role in human health. Sources of Iodine;-Dietary Sources: Iodized Salt: The most common source of iodine.  Dairy Products: Milk and other dairy items.  Fortified Foods: Certain foods fortified with iodine. Seafood: Especially salty water fish.  Plant Foods: Vegetables and grains grown in iodine-rich soil. Body Requirements  Daily Requirement: The normal amount of iodine required for  Importance of Iodine  ThyroidHealth: Iodine is vital for the production of thyroid hormones, which regulate metabolism, heart health, and more. The thyroid gland absorbs iodine in small amounts to produce these hormones. Health Conditions Related to Iodine  Hypothyroidism: A condition that can occur due to insufficient iodine, leading to decreased production of thyroid hormones.  Goiter: An enlarged thyroid gland that can result from distributed so part of the molecule is partially positive, while part is partially negative. In diagrams, the lowercase letter delta (δ) shows the charge distribution in a polar molecule. The positive charge comes from the protons in the atomic nucleus, while the negative charges comes from the electrons. Each hydrogen atom in a water molecule has one electron that spends most of its time between the hydrogen and oxygen nucleus, leaving the hydrogen nucleus more exposed than if the electron wasn’t part of a chemical bond. The hydrogen atoms carry a partial positive charge. Meanwhile, the oxygen atom has two unbound electron pairs that are as far as possible from each other and the chemical bonds, giving the oxygen atom a partial negative charge. To understand why a water molecule is polar, while similar-seeming molecules (e.g., carbon dioxide or CO2) are not polar, you need to understand the roles of electronegativity and molecular geometry  Electronegativity and the Polarity of Water in polarity.  Atoms with different electronegativity values form polar bonds. If the electronegativity difference is large enough (e.g., between a metal and a nonmetal), a highly polar ionic bond forms. Slight differences between atoms (e.g., two different nonmetals) lead to polar covalent bond formation. Electrons participating in a polar covalent bond spend more time closer to one atom than the other, leading to partial positive Molecular Geometry and the Polarity of Water But, molecular geometry also plays a part in molecule polarity. Although the covalent bonds between carbon and oxygen are polar in carbon dioxide (CO2), the molecule is not polar. This is because carbon dioxide is a linear molecule and the partial positive and negative charges effectively cancel each other out. In other words, its net dipole moment is zero. Unlike carbon dioxide, water is not a linear Molecular Geometry and the Polarity of Water But, molecular geometry also plays a part in molecule polarity. Although the covalent bonds between carbon and oxygen are polar in carbon dioxide (CO2), the molecule is not polar. This is because carbon dioxide is a linear molecule and the partial positive and negative charges effectively cancel each other out. In other words, its net dipole moment is zero. Unlike carbon dioxide, water is not a linear The reason water has a bent geometry is because the oxygen atom has two lone electron pairs. The electronic structure of oxygen is 1s2 2s2 2p4. Each hydrogen atom contributes one electron to fill the valence shell and give oxygen 1s2 2s2 2p6, but this means four of the electrons (2 pairs) in the 2p shell aren’t participating in a chemical bond. The electron pairs have the same negative electrical charge, so they repel each other. They are also repelled by the chemical bonds between the hydrogen and  Why Water Is a Polar Solvent The shape and polarity of the water molecule affects its interaction with other water molecules and with other compounds. The reason water is a polar solvent is because it attracts either a positive or negative electrical charge of a solute. The oxygen atom’s partial negative charge attracts hydrogen atoms from other water molecules and positive regions from other molecules. Meanwhile, hydrogen’s partial positive charge attracts oxygen atoms from other water molecules and negative regions of other molecules. The attraction between oxygen and hydrogen atoms of neighboring water molecules leads to hydrogen bond formation. Hydrogen bonds aren’t as strong as covalent bonds and not all water molecules in a sample participate in them. At any given time, about 20% of water molecules are free to interact with other chemical species. This interaction is called dissolving or hydration. It is a key property of water that gives