Biological Molecules
Graphic Organizer

Lipids

Fatty Acids and Structure

Fatty Acid Variability: Fatty acids can vary in length (number of carbon atoms) and saturation (presence of double bonds).

Cis vs. Trans Fats: Cis fats have hydrogen atoms on the same side of the double bond, while trans fats have them on opposite sides, and they are often considered unhealthy.

Types and Functions:

Phospholipid Bilayer: Phospholipids arrange themselves in a bilayer in cell membranes due to their amphipathic nature.

HDL vs. LDL Cholesterol: High-Density Lipoprotein (HDL) is considered "good" cholesterol, while Low-Density Lipoprotein (LDL) is "bad" cholesterol.

Lipid Properties and Storage:

Lipid Solubility: Lipids are nonpolar and hydrophobic, making them insoluble in water.

Lipid Storage: Adipose tissue stores excess energy in the form of triglycerides.

Lipid Hormones: Lipids, such as steroids, serve as hormones (e.g. sex hormones).

Lipid Digestion and Membrane Fluidity:

Lipid Digestion: Enzymes like lipase break down dietary fats into fatty acids and glycerol.

Fat-Soluble Pigments: Lipids can carry fat-soluble pigments

Lipid Bilayer Fluidity: The fluidity of cell membranes is influenced by the types of lipids present and their degree of saturation.

Nucleic Acids

Types of Nucleic Acids and Genetic Information:

Includes DNA, RNA and Adenosine Triphosphate (ATP)

DNA: makes up genetic material and makes instructions for proteins

RNA: Involved in making proteins

ATP:Created in the mitochondria and is used as energy in the cell

Nucleotides

Monomer unit for all Nucleic Acids

Composed of sugar, phosphate group, and nitrogen base (adenine (A), thymine (T), guanine(G), cytosine(C))

DNA and RNA

DNA:
Double-stranded helix.
Composed of deoxyribose sugar.
Nitrogen bases: adenine, cytosine, guanine, thymine.

RNA:
Single-stranded helix.
Composed of ribose sugar.
Nitrogen bases: adenine, guanine, cytosine, uracil.

Adenosine Triphosphate (ATP):

Composed of three phosphate groups, one ribose (sugar), and one nitrogen base.
Dehydration synthesis of ATP from ADP + P requires energy (endergonic reaction).
Hydrolysis of ATP to ADP + P releases energy (exergonic reaction).

Cellular Structure

Cells are the basic units of life, categorized as prokaryotic or eukaryotic.

Understanding Sizes

Cells have various components with different sizes.
An interactive tool helps visualize object sizes.
Metric prefixes help calculate relative sizes.

Technology

Tools like electron microscopes reveal cellular details.
Choice of technology depends on structure size.

Although the size of a cell is very small. The cell does a lot of things for living things to function.

Water

Water's Unique
Properties

Hydrogen Bonding: Water molecules are held together by hydrogen bonds, forming between the positively charged hydrogen atoms of one molecule and the negatively charged oxygen atoms of another
Cohesion: Water molecules are attracted to each other due to hydrogen bonding, resulting in high cohesion and surface tension.

Adhesion: Water molecules can adhere to other substances due to their polarity, allowing them to climb against gravity in narrow tubes through capillary action.
Universal Solvent: Water is often referred to as the "universal solvent" because it can dissolve a wide range of substances due to its polarity.

Thermal
Properties

Heat Capacity: Water has a high specific heat capacity, meaning it can absorb and store a significant amount of heat without significant temperature changes. This property helps stabilize temperatures in living environments.
Heat of Vaporization: Water requires a substantial amount of heat energy to change from a liquid to a gas, making it essential for cooling mechanisms like sweating in animals.

Density Anomaly: Water is densest at 4°C, causing ice to float on water. This property is vital for insulating bodies of water and preventing complete freezing in aquatic ecosystems.

Phase Transitions: Water exists in three phases under normal conditions: solid (ice), liquid (water), and gas (water vapor).

Chemical
Characteristics

Ionization: Water molecules can ionize into H+ (hydrogen ions) and OH- (hydroxide ions), serving as the basis for measuring acidity and alkalinity on the pH scale.

Biological
Significance

Transport Medium: In organisms, water serves as a medium for transporting essential nutrients, gases, and waste products.

Thermal Regulation: Water plays a crucial role in regulating temperature in organisms through processes like sweating and evaporative cooling.

Lubrication: Water provides lubrication for joints and body cavities in animals, facilitating smooth movement and reducing friction.

Hydration: Proper hydration with water is essential for maintaining bodily functions and preventing dehydration.

Role in Ecosystems: Surface water bodies, such as oceans, lakes, and rivers, play significant roles in the Earth's climate, ecosystems, and as valuable resources for human activities.

Carbohydrates

Monosaccharide Properties:

Isomers: Glucose and galactose are isomers, sharing the same molecular formula but having different structures.

Monosaccharide Structure: Monosaccharides often adopt ring forms in aqueous solutions due to their tendency to form cyclic structures.

Shape in Solution: Carbohydrates can take on helical or linear shapes based on their specific molecular structure.

Carbohydrate Bonding and Complexity:

Polysaccharide Varieties: Polysaccharides can be branched or unbranched, serving various functions (e.g., cellulose for structure, glycogen for energy storage).

Disaccharide Formation: Disaccharides form when two monosaccharides join through a glycosidic bond.

Monosaccharide Diversity: Besides glucose and fructose, numerous other monosaccharides exist, including ribose, deoxyribose, and mannose.

Biological and Functional Aspects:

Glycoproteins: Carbohydrate chains attached to cell surface proteins (glycoproteins) are vital for cell recognition and communication.

Hydrophilic Nature: Carbohydrates are hydrophilic, making them soluble in water.

Sweetness: Different sugars vary in sweetness, with fructose being sweeter than glucose.

The glycemic index measures how quickly carbohydrates raise blood sugar levels, with high-GI foods causing rapid spikes.

Digestion and Health Implications:

Cellulose Digestion: Humans lack the enzymes required to digest cellulose, but it serves as dietary fiber.

Digestion: Carbohydrates are broken down into simpler sugars, like glucose, during the digestion process.

Lactose Intolerance: Inability to digest lactose (milk sugar) results from a deficiency of the enzyme lactase and can lead to digestive discomfort.

Proteins

Protein Structure and Function:

Enzymes are highly specific, recognizing only certain substrates based on their shape and chemical properties.

Enzyme-Substrate Complex: The temporary binding of an enzyme and its substrate forms an enzyme-substrate complex, facilitating chemical reactions.

Lock-and-Key Model: Describes enzyme-substrate interaction as a specific fit, much like a lock and key.

Enzyme Regulation and Interaction:

Molecules like vitamins can act as coenzymes and assist enzymes in catalyzing reactions.

Protein Denaturation: Proteins can lose their shape (denature) due to factors like high heat, extreme pH, or chemicals.

Activation Energy: Enzymes lower the activation energy required for chemical reactions to occur.

Protein Roles and Interactions

Protein Structure: Multiple polypeptide chains come together to form a protein with a quaternary structure (e.g., hemoglobin).

Protein Folding: Chaperone proteins help newly synthesized proteins fold correctly.

Protein Conformation: The specific three-dimensional shape of a protein is crucial for its function.

Protein Diversity and Structure:

Protein-DNA Interactions: Proteins like transcription factors bind to DNA to regulate gene expression.