Biological molecules, module 2

Water

A vital substance for life, comprising hydrogen and oxygen, that serves as the medium for metabolic reactions in cells.

Covalent Bonding

The type of bond formed when atoms share electrons, as seen in the combination of hydrogen and oxygen in water.

Dipole

A separation of electric charge within a molecule, leading to one end being slightly positive and the other slightly negative.

Polar Molecule

A molecule that has a distribution of charge leading to distinct positive and negative regions, such as water.

Hydrogen Bond

A weak bond that occurs between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of another.

Solvent

A substance capable of dissolving other substances, allowing for chemical reactions to occur in solution.

Specific Heat Capacity

The amount of energy required to raise the temperature of 1 kg of a substance by 1°C, which is relatively high for water.

Latent Heat of Vaporisation

The amount of energy required to convert a unit mass of a substance from liquid to gas without a change in temperature.

Cohesion

The property of water molecules to stick together due to hydrogen bonding, contributing to surface tension.

Density

The mass per unit volume of a substance; water is less dense as a solid (ice) than as a liquid, allowing ice to float.

Metabolite

A substance involved in or produced by metabolism, which can be efficiently transported in water.

Universal Solvent

A term describing water's ability to dissolve a wide variety of substances due to its polar nature.

Thermal Energy

The energy that comes from the temperature of matter, which is required to break and form bonds in water.

Hydrogen Bonds

Weak attractions between the hydrogen atom of one water molecule and the oxygen atom of another, responsible for many of water's unique properties.

Adhesion

The attraction between water molecules and different substances, enabling water to climb up structures like plant xylem.

Latent Heat of Vaporization

The amount of energy required to convert water from liquid to gas, which plays a crucial role in cooling organisms.

Surface Tension

The elastic-like force existing at the surface of water due to cohesive forces, allowing insects to walk on water.

Transpiration

The process by which water evaporates from the leaves of plants, helping to regulate temperature and nutrient transport.

Optimal Temperature for Enzyme Activity

The specific temperature range in which enzymes function most effectively, often maintained by water's thermal properties.

Solvent Properties

The ability of water to dissolve a wide range of substances due to its polar nature, facilitating biochemical reactions.

Blood Plasma:

The liquid component of blood that helps in heat transfer and maintaining a constant body temperature.

Monomer:

A small, basic molecular unit that can join together with other similar units to form a larger molecule.

Polymer:

A large molecule composed of many repeating structural units (monomers) bonded together.

Macromolecule:

A very large molecule, typically composed of thousands of atoms, which can include polymers but is not limited to them.

Polymerisation:

The process by which monomers chemically bond together to form a polymer.

Covalent Bond:

A type of chemical bond where two atoms share one or more pairs of electrons.

Condensation Reaction:

A chemical reaction in which two molecules combine to form a larger molecule, with the loss of a small molecule, often water.

Hydrolysis:

A chemical process in which a molecule is split into smaller units by the addition of water, breaking covalent bonds.

Dehydration Synthesis

Another term for condensation reaction, emphasizing the removal of water during the formation of covalent bonds.

Nucleotide:

The monomer unit of nucleic acids, consisting of a nitrogenous base, a sugar, and a phosphate group.

Triglyceride:

A type of lipid formed from glycerol and three fatty acids, not classified as a polymer due to the nature of its bonding.

Carbohydrates:

Organic compounds made up of carbon, hydrogen, and oxygen, typically in a 2:1 ratio of hydrogen to oxygen, serving various functions including energy source and structural roles.

Monosaccharides:

The simplest form of carbohydrates, consisting of single sugar molecules like glucose and fructose. A simple sugar that cannot be hydrolyzed into smaller carbohydrate units, serving as a building block for more complex carbohydrates.

Disaccharides:

Carbohydrates formed by the combination of two monosaccharides, such as sucrose and lactose.

Polysaccharides:

Complex carbohydrates composed of long chains of monosaccharide units, such as starch and glycogen.

Lipids:

A diverse group of hydrophobic organic compounds, including fats and oils, primarily composed of carbon, hydrogen, and oxygen, serving as energy storage and structural components.

Phospholipids:

Lipids that contain a phosphate group, essential for forming cellular membranes.

Proteins:

Large, complex molecules made up of amino acids, containing carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur, serving various functions such as enzymes and structural components.

Amino Acids:

The building blocks of proteins, consisting of an amino group, a carboxyl group, and a unique side chain.

Nucleic Acids

:Biological macromolecules, including DNA and RNA, composed of nucleotides and responsible for storing and transmitting genetic information.

DNA:

A type of nucleic acid that carries the genetic blueprint for living organisms, composed of two strands forming a double helix.

RNA:

A nucleic acid involved in protein synthesis and gene expression, typically single-stranded.

Cellulose:

A polysaccharide that serves as a structural component in plant cell walls, providing rigidity.

Glycogen:

A polysaccharide that serves as a form of energy storage in animals, primarily found in the liver and muscles.

Cholesterol:

A type of lipid that is a component of cell membranes and a precursor for steroid hormones.

Enzymes:

Proteins that act as biological catalysts, speeding up chemical reactions in the body.

Antibodies:

Proteins produced by the immune system to identify and neutralize foreign objects like bacteria and viruses.

Hormones:

Chemical messengers, often proteins or steroids, that regulate physiological processes in the body.

Reducing Sugar:

A sugar that can donate electrons, allowing it to reduce other compounds, typically identified by a color change in Benedict's test.

Non-reducing Sugar:

A sugar that cannot donate electrons and must be hydrolyzed into monosaccharides before it can be tested for reducing properties.

Benedict's Test:

A qualitative test used to detect reducing sugars, where a color change indicates the presence of these sugars.

Isomer:

Compounds that have the same molecular formula but different structural arrangements, leading to different properties.

Alpha (α) Glucose:

One of the two isomers of glucose, characterized by the orientation of the hydroxyl group on the first carbon.

Beta (β) Glucose:

The isomer of glucose where the hydroxyl group on the first carbon is oriented in the opposite direction compared to alpha glucose.

Pentose Sugar:

A monosaccharide containing five carbon atoms, important in the structure of nucleotides.

Ribose:A

A pentose sugar that is a component of RNA, characterized by its five carbon atoms and hydroxyl groups.

Deoxyribose:

A pentose sugar similar to ribose but lacking one oxygen atom, essential for DNA structure.

Glycosidic Bond:

A covalent bond formed between two monosaccharides through a condensation reaction, linking their hydroxyl groups.

Disaccharide:

A carbohydrate formed from two monosaccharides linked by a glycosidic bond.

Polysaccharide:

A complex carbohydrate composed of long chains of monosaccharide units bonded together.

Trioses:

Monosaccharides that contain three carbon atoms, such as glyceraldehyde.

Hexoses:

Monosaccharides that contain six carbon atoms, with glucose being the most well-known example.

Hydrolysis Reaction:

A chemical process that involves the breaking down of a compound by the addition of water, often used to separate disaccharides into monosaccharides.

Maltose:

A disaccharide formed from two α-glucose units, commonly produced during the digestion of starch.

Sucrose:

A non-reducing disaccharide composed of glucose and fructose, commonly known as table sugar.

Lactose:

A disaccharide sugar found in milk, composed of glucose and galactose.

Hydrolytic Enzymes:

Enzymes that catalyze the hydrolysis of compounds, breaking down larger molecules into smaller ones by adding water.

α-1,4 Glycosidic Bond:

A specific type of glycosidic bond that connects the first carbon of one sugar to the fourth carbon of another, typically found in maltose.

α-1,2 Glycosidic Bond:

A type of glycosidic bond that connects the first carbon of one sugar to the second carbon of another, found in sucrose.

Hydrolysis of Sucrose:

The process in which sucrose is broken down into glucose and fructose through the addition of water, often catalyzed by acid.

Amylopectin:

A highly branched polysaccharide that is a component of starch, consisting of glucose monomers linked by glycosidic bonds.

Starch:

A storage polysaccharide in plants, composed of two components: amylose and amylopectin.

Amylose:

A linear polymer of α-glucose molecules connected by 1,4 glycosidic bonds, forming a helical structure.

β-Glucose:

An isomer of glucose that is used in the formation of cellulose, requiring a 180° rotation for bonding.

Storage Polysaccharide:

A type of polysaccharide that serves as an energy reserve, such as starch and glycogen.

Amyloplasts:

Organelles in plant cells responsible for storing starch granules.

Liver and Muscle Cells:

Cells with high concentrations of glycogen, visible as granules, due to their high rates of cellular respiration.

Branching in Glycogen:

The structure that allows for more free ends for glucose addition or removal, enabling rapid condensation and hydrolysis.

Tensile Strength of Cellulose:

The ability of cellulose to withstand stretching without breaking, allowing cell walls to endure turgor pressure.

Cellulose Matrix:

A combination of cellulose fibers and other molecules that enhances the strength of plant cell walls.

Permeability of Cellulose:

The property that allows water and solutes to pass through cellulose fibers freely.

Cellulase:

An enzyme that few organisms possess, necessary for hydrolyzing cellulose.

Reducing Sugars:

Sugars that can donate electrons, leading to their oxidation and classification as reducing agents.

Benedict's Test:

A qualitative test for reducing sugars that involves a color change in the presence of copper (I) oxide.

Copper (II) Sulfate:

A component of Benedict's reagent that reacts with reducing sugars to form a colored precipitate.

Color Scale in Benedict's Test:

A range from blue (no reducing sugar) to brown/brick-red (high concentration of reducing sugar), indicating the presence of reducing sugars.

Starch Test:

A test for the presence of starch, which involves adding iodine solution that changes color to blue-black in the presence of starch.

Saturated Fatty Acid:

A fatty acid with no double bonds between carbon atoms, typically solid at room temperature and found in animal fats.

Unsaturated Fatty Acid:

A fatty acid that contains one or more double bonds in its hydrocarbon chain, usually liquid at room temperature and found in plant oils.

Cis-Fatty Acids:

nsaturated fatty acids where hydrogen atoms are on the same side of the double bond, allowing for enzyme metabolism.

Trans-Fatty Acids

:Unsaturated fatty acids with hydrogen atoms on opposite sides of the double bond, which are not metabolized by enzymes and are linked to health risks.

Phospholipid:

A type of lipid that consists of two fatty acids and a phosphate group attached to a glycerol molecule, forming a bilayer in cell membranes.

Ester Bond:

A covalent bond formed between a hydroxyl group of glycerol and a carboxyl group of a fatty acid during the formation of triglycerides.

Hydrophobic:

Describes a substance that does not interact well with water, often repelling it.

Hydrophilic:

Describes a substance that interacts well with water, often being soluble in it.

Amphipathic

:Refers to molecules that have both hydrophobic and hydrophilic parts, such as phospholipids.

Fatty Acid:

A carboxylic acid with a long hydrocarbon chain, which can be saturated or unsaturated, and is a key component of lipids.

Energy Storage:

The function of triglycerides to store energy in the form of fat, which can be metabolized for ATP production.

Buoyancy:

The ability of fats and oils to help organisms float in water, often due to their low density.

Insulation:

The function of lipids to retain body heat and protect against temperature changes.