Biological Molecules: Monomers, Polymers, and Lipids

Comprehensive vocabulary flashcard set covering monomers, polymers, lipid structures, synthesis, reactions, health implications, and biological functions based on the lecture notes.

Monomer

A small single unit that links together with other units to form larger polymer molecules.

Polymer

A large molecule made up of many repeating smaller units called monomers linked together.

Condensation reaction

A chemical reaction in which two monomers link together, forming a covalent bond and eliminating a molecule of water.

Polymerisation

The linking of identical monomers through many condensation reactions to form very large polymers.

Hydrolysis reaction

A chemical reaction that breaks down polymers into monomers by the chemical insertion of a water molecule to break a bond.

Covalent bond in polymers

The type of chemical bond formed between monomers during a condensation reaction.

Lipids

Biological molecules made from carbon, hydrogen, and oxygen that are insoluble in water but soluble in organic solvents.

Elemental composition of lipids

Carbon, hydrogen, and oxygen, containing proportionally less oxygen than carbohydrates.

Lipid solubility in water

Insoluble; lipids do not dissolve in water.

Lipid solubility in organic solvents

Soluble in organic solvents, such as ethanol.

Fats

Lipids that are solid at room temperature, such as butter and lard.

Oils

Lipids that are liquid at room temperature, such as olive oil.

Subunits of triglycerides

Glycerol and fatty acids.

Why triglycerides are not polymers

They are made up of two different subunits (glycerol and fatty acids) with different structures, rather than identical repeating monomers.

Glycerol

An alcohol present in both triglycerides and phospholipids with the chemical formula $C_3H_8O_3$.

Glycerol chemical formula

$$C_3H_8O_3$$

Glycerol constancy in lipids

A structural component that remains constant across all triglyceride and phospholipid molecules.

Non-polar nature of triglycerides

A property of triglycerides that makes them hydrophobic and insoluble in water.

Hydrophobic

Water-repelling or insoluble in water.

Hydrophilic

Attracted to water.

Cholesterol

A type of lipid categorized alongside fatty acids, phospholipids, and triglycerides.

Fatty acid

A molecule consisting of a methyl group ($CH_3$), a hydrocarbon chain ($(CH_2)_n$), and a carboxyl group ($COOH$).

Methyl group in fatty acids

The terminal $CH_3$ group at one end of a fatty acid molecule.

Hydrocarbon chain in fatty acids

The middle section of a fatty acid represented by $(CH_2)_n$, which varies in length.

Carboxyl group in fatty acids

The $COOH$ group present at one end of a fatty acid molecule.

Variation in lipid structure

Diversity in lipid structure caused by the many different types and chain lengths of fatty acids.

Saturated fatty acid

A fatty acid whose hydrocarbon chain contains no carbon-to-carbon double bonds and holds the maximum number of hydrogen atoms.

Unsaturated fatty acid

A fatty acid whose hydrocarbon chain contains one or more carbon-to-carbon double bonds and does not hold the maximum number of hydrogen atoms.

Lauric acid

An example of a saturated fatty acid containing only single bonds in its hydrocarbon chain.

Palmitoleic acid

An example of an unsaturated fatty acid containing a carbon-to-carbon double bond.

Straight chain hydrocarbon

The structural shape formed by the hydrocarbon chain of a saturated fatty acid due to having only single bonds.

Monounsaturated fatty acid

An unsaturated fatty acid that contains exactly one carbon-to-carbon double bond in its hydrocarbon chain.

Polyunsaturated fatty acid

An unsaturated fatty acid that contains many carbon-to-carbon double bonds in its hydrocarbon chain.

Saturated triglycerides physical state

Solid at room temperature.

Unsaturated triglycerides physical state

Liquid at room temperature.

Animal fats

Fats derived from animals that primarily consist of saturated fatty acids and are solid at room temperature.

Plant oils

Oils derived from plants that primarily consist of unsaturated fatty acids and are liquid at room temperature.

Triglyceride formation

The process where one glycerol molecule bonds with three fatty acid molecules through three condensation reactions.

Ester bond

The chemical bond formed between glycerol and a fatty acid during a condensation reaction in lipids.

Ester bonds per triglyceride

Three ester bonds are formed in one triglyceride molecule.

Condensation reactions per triglyceride

Three condensation reactions are needed to synthesize one triglyceride molecule.

Water molecules eliminated per triglyceride

Three molecules of water ($3 \times H_2O$) are eliminated during the synthesis of one triglyceride.

Origin of oxygen in an ester bond

The oxygen atom on the glycerol molecule forms part of the ester bond.

Origin of oxygen in eliminated water during esterification

The oxygen atom from the carboxyl group of the fatty acid becomes part of the eliminated $H_2O$ molecule.

Triglyceride breakdown

The breakdown of triglycerides by hydrolysis to form glycerol and three fatty acids.

Phospholipid structure

A lipid molecule composed of one glycerol, two fatty acids, and one phosphate group.

Phosphate group in phospholipids

The polar, hydrophilic head component that replaces one of the three fatty acids found in a triglyceride.

Fatty acid content in phospholipids

Two fatty acids attached to a glycerol molecule.

Hydrophobic tail of phospholipids

The two fatty acid tails that repel water.

Hydrophilic head of phospholipids

The polar head group that is attracted to water.

Phospholipid role in cell membranes

An important component of cell membranes due to having hydrophilic heads and hydrophobic tails.

High saturated fat intake health risks

Increases the risk of heart disease by damaging the heart and coronary arteries.

Coronary arteries

Blood vessels supplying the heart that can be damaged by high intake of saturated fats.

Atherosclerosis

A condition involving plaque formation and growth inside artery walls, causing them to narrow.

Aneurysm

A health issue linked to artery damage that involves the weakening of artery walls.

Myocardial infarction

A heart attack that can occur when narrowed arteries are blocked by a blood clot.

Low density lipoproteins (LDLs)

Lipoproteins that transport lipids to tissues, including artery walls, where they contribute to plaque formation.

LDLs and heart disease risk

Higher levels of LDLs contribute to plaque formation (atherosclerosis) and increase heart attack risk.

LDLs relationship with dietary fats

More saturated fats in the diet result in higher levels of LDLs.

High density lipoproteins (HDLs)

Lipoproteins that remove excess lipids from tissues and transport them to the liver for disposal.

HDLs and heart disease risk

Higher levels of HDLs reduce heart disease risk.

HDLs relationship with dietary fats

More unsaturated fats in the diet result in higher levels of HDLs.

Destination of lipids transported by HDLs

The liver, where excess lipids are sent for disposal.

Atherosclerosis stage 1

Beginning of plaque formation inside a healthy artery.

Atherosclerosis stage 2

Increased plaque accumulation inside the arterial wall.

Atherosclerosis final stage

A narrowed artery becomes completely blocked by a blood clot.

Weakening of artery walls

A structural arterial damage condition linked to plaque accumulation and aneurysm development.

Lipid function: Energy storage

Lipids store large amounts of energy (more per gram than carbohydrates), providing a lightweight energy store.

Lipid energy content vs Carbohydrates

Lipids yield more energy per gram than carbohydrates.

Lightweight energy store example

Seeds, which utilize lipids for efficient lightweight energy storage.

Lipid function: Protection

Lipids act as shock absorption to protect vital internal organs.

Shock absorption by lipids

The mechanism by which fat deposits cushion and protect vital organs from physical shock.

Lipid function: Thermal insulation

Lipids reduce heat loss from the body of an organism.

Blubber

A layer of fat in marine mammals that provides thermal insulation to reduce heat loss.

Lipid function: Buoyancy

Lipids are less dense than water, helping aquatic organisms float.

Density of lipids relative to water

Lipids are less dense than water, aiding buoyancy.

Lipid function: Metabolic water

Water produced internally when lipids are broken down during aerobic respiration.

Aerobic respiration of lipids

The metabolic process that breaks down fat store reserves to yield energy and metabolic water.

Camel's hump function

An organ made of fat that produces metabolic water when broken down via aerobic respiration in desert conditions.

Lipid function: Waterproofing

Hydrophobic waxes reduce water loss from surfaces such as insect exoskeletons and plant leaves.

Waxes in exoskeletons

Hydrophobic lipid coatings on insects that reduce water loss.

Waxes in plant cuticles

Hydrophobic lipid coatings on plant leaves that reduce water loss.

Carbon-to-carbon double bond in fatty acids

A double bond structure present in unsaturated fatty acids that prevents the chain from holding the maximum number of hydrogen atoms.

Carbon-to-carbon single bond in fatty acids

A single bond structure present in saturated fatty acids allowing maximum hydrogen atom binding.

Butter and lard

Examples of solid fats at room temperature composed of saturated lipids.

Olive oil

An example of a liquid oil at room temperature composed of unsaturated lipids.

Ethanol lipid solvent

An organic solvent in which lipids are soluble.

Three main parts of a fatty acid

A methyl group ($CH_3$), a hydrocarbon chain ($(CH_2)_n$), and a carboxyl group ($COOH$).

Formula of a methyl group

$$CH_3$$

Formula representation of a hydrocarbon chain

$$(CH_2)_n$$

Formula of a carboxyl group

$$COOH$$

Polar head group of phospholipids

The hydrophilic region composed of glycerol and a phosphate group.

Non-polar tail group of phospholipids

The hydrophobic region made of two fatty acids.

Four-chain polymer diagram reaction

A process where three condensation reactions join four individual monomers into a four-chain polymer.

Polymer to monomer reaction

Hydrolysis, which requires adding water to break chemical bonds.

Monomer to polymer reaction

Condensation, which links monomers together while eliminating water molecules.

Heart disease risk reduction

Associated with higher levels of HDLs, which remove excess lipids and transport them to the liver.

Blood clot formation in arteries

The blocking mechanism in a narrowed artery that causes severe cardiovascular issues such as a myocardial infarction.

Desert animal adaptation via lipids

Using fat reserves (such as a camel's hump) to generate metabolic water via aerobic respiration.

Ratio of fatty acids to glycerol in phospholipids

Two fatty acids to one glycerol molecule.