Lecture Notes on Water, Carbohydrates, Lipids, and Amino Acids

Vocabulary flashcards based on lecture notes about water, carbohydrates, lipids, and amino acids.

Properties of Water

Water molecules move freely, but hydrogen bonds create high boiling point and viscosity. Water remains liquid over a wide range of temperatures.

Roles of Water

Provides habitat for aquatic life, major component in tissues and medium for chemical reactions, and transports materials (e.g., blood).

Density of Water

Water is less dense than ice (hydrogen bonds hold molecules apart). Ice insulates water below, allowing aquatic life to survive winter, and provides stability in aquatic environments.

Water as a Solvent

Polar nature dissolves ionic and polar substances (salts, glucose), medium for transport of nutrients and waste for metabolic reactions.

Cohesion and Surface Tension

Water molecules stick together. Supports small organisms on water, helps in transpiration to pull water in plants, and allows pond skaters to walk on water.

High Latent Heat of Vaporization

High energy needed to break hydrogen bonds and evaporate water. Cooling surface mechanism (e.g., sweating, transpiration).

High Specific Heat Capacity (SHC)

Water absorbs a large amount of heat with little temperature change. Maintains stable aquatic and cellular environments.

Water as a Reactant

e.g., photosynthesis, hydrolysis. Reactant in biochemical processes and essential for metabolic reactions.

Carbohydrates

General formula (CH2O)n. Made of glucose monomers.

Pentose Monosaccharides

Contain 5 carbon atoms. Two pentose sugars are ribose and deoxyribose. Important constituents of RNA and DNA. Ribose has one -OH group attached to Carbon 2, whereas deoxyribose has 2 H atoms and one -OH group

Lactose

glucose + galactose; 1,4-glycosidic bond

Maltose

glucose + glucose; 1,4-glycosidic bond

Sucrose

glucose + fructose

Glucose

soluble, can be easily transported around the body, can be easily digested, stores energy which can be released in respiration

Good Energy Stores

Small and compact. Branched chains allow for many glucose molecules to hydrolyze at once.

Polysaccharides

Not soluble, therefore don't change the water potential.

Amylose

1-4 glycosidic bond. Coils up into a helix shape. Hydrogen bonds are situated on the inside of the coil to keep its shape. Compact and insoluble.

Amylopectin

1,4 glycosidic bond and 1,6 glycosidic bond (branch). Insoluble, many branches more bonds. Can be easily broken and reformed to release energy. Coils slightly.

Glycogen

Highly branched (1,6 - glycosidic bonds) - glucose can be released quickly. Compact, insoluble, and metabolically inactive - stable energy store.

Cellulose

Beta glucose. B-1,4-glycosidic bonds. Hydrogen bonds are weak but there are many, so it adds Extra Strength. Every other beta glucose flips to get the OH groups facing the same way so they can go under a condensation reaction. arranged to make microfibrils macrofibrils.

Triglycerides

Made up of a glycerol and 3 fatty acids linked by ester bonds. Energy source, protection, insulation, buoyancy.

Phospholipid

Contains a hydrophilic head and hydrophobic carbon chain. Can form membranes around cells and organelles. Selectively permeable when exposed to water, it can form a phospholipid bilayer or a micelle.

Cholesterol

Adds stability in the membrane. Regulates fluidity, preventing it from becoming too fluid or stiff. Small hydrophobic molecules which means it can sit in the middle of the hydrophobic part of the bilayer.

Amino Acids as Buffers

Amino acids can act as buffers by giving or taking in H+ ions to maintain a neutral pH environment.

Primary Structure of a Protein

Sequence of amino acids.

Secondary Structure of a Protein

Coiling/folding (alpha helix, beta-pleated sheet) due to hydrogen bonds.

Tertiary Structure of a Protein

3D shape from interactions between side chains (R group). Hydrogen bonds, ionic bonds, disulfide bridges, hydrophobic interactions.

Quaternary Structure of a Protein

Assembly of multiple polypeptides.

Fibrous Proteins

long and thin, insoluble, structural.

Globular Proteins

Spherical, soluble, metabolic.

Examples of Fibrous Proteins

collagen, keratin

Examples of Globular Proteins

haemoglobin, insulin