Biology: Polymers, Carbohydrates, and Lipids

What is a polymer?

a molecular chain built from repeating building blocks called monomers.

How are polymers built?

built through dehydration reactions that produce water and require energy and enzymes.

What process breaks down polymers?

Hydrolysis breaks down polymers into monomers, consumes water, releases energy, and requires enzymes.

Which biomolecules form polymers?

Carbohydrates, proteins, and nucleic acids form polymers.

What are macromolecules?

Carbohydrates, proteins, and nucleic acids are macromolecules; lipids are not considered polymers or macromolecules.

List four roles of carbohydrates.

1. Energy source (e.g., glucose) 2. Carbon source (e.g., glucose) 3. Energy storage (e.g., starch, glycogen) 4. Structural material (e.g., cellulose, chitin, peptidoglycan)

What are the structural features of monosaccharides?

a carbon chain backbone, hydroxyl (-OH) groups, one carbonyl group, and a general formula of (CH₂O)n.

What is the difference between α-glucose and β-glucose?

In α-glucose, the hydroxyl group on carbon 1 points below the ring; in β-glucose, it points above the ring.

How are polysaccharides assembled?

form through dehydration reactions between hydroxyl groups of monosaccharides, producing water and forming covalent glycosidic bonds.

What are disaccharides?

two monosaccharides joined together.

What are oligosaccharides?

chains of 3-50 monosaccharides, often found on cell surfaces.

What is the difference between starch and glycogen?

Both are polymers of α-glucose; starch is found in plants and is less branched, while glycogen is found in animals and has more branching.

What is the function of cellulose in plants?

provides structural support in plant cell walls.

What are the roles of lipids?

serve as energy sources, carbon sources, energy storage, structural roles in cells, cell-to-cell signaling (hormones), and cell chemistry (fat-soluble vitamins).

What are the structural features of fatty acids?

a carboxyl group at one end, a long hydrocarbon chain, and a methyl group at the opposite end.

What is the difference between saturated and unsaturated fats?

Saturated fats have no C=C double bonds, while unsaturated fats have one or more C=C double bonds.

What is the structure of phospholipids?

consist of 2 fatty acids, 1 glycerol, 1 phosphate group, and 1 additional chemical group, making them amphipathic.

What is the significance of branching in glycogen?

More branch points in glycogen create more chain ends for enzymes to access, allowing faster glucose release.

What is chitin?

structural polysaccharide found in fungal cell walls and arthropod exoskeletons, made from N-acetylglucosamine.

What is peptidoglycan?

a structural polysaccharide that forms bacterial cell walls.

What is the typical cellular structure of monosaccharides in aqueous environments?

usually form rings in aqueous environments.

What is the general formula for monosaccharides?

monosaccharides is a multiple of (CH₂O)n.

What are carbohydrates primarily composed of?

carbon, hydrogen, and oxygen.

What is the basic structure of a carbohydrate?

typically have a general formula of (CH2O)n, where n is the number of carbon atoms.

What are the two main types of carbohydrates?

Simple carbohydrates (monosaccharides and disaccharides) and complex carbohydrates (polysaccharides).

What is a monosaccharide?

The simplest form of carbohydrates, consisting of a single sugar unit, such as glucose or fructose.

What is a disaccharide?

A carbohydrate formed by the combination of two monosaccharides, such as sucrose (glucose + fructose).

What are polysaccharides?

Carbohydrates that consist of long chains of monosaccharide units, such as starch, glycogen, and cellulose.

What is the primary function of carbohydrates?

To provide energy and serve as structural components in cells.

What are lipids?

a diverse group of hydrophobic molecules, including fats, oils, waxes, and steroids.

What is the structure of a triglyceride?

consists of one glycerol molecule and three fatty acid chains.

What is the role of cholesterol in the body?

serves as a precursor for steroid hormones, vitamin D, and bile.

What is a phospholipid?

A type of lipid that forms a bilayer in cell membranes, consisting of hydrophilic heads and hydrophobic tails.

What is the significance of the phospholipid bilayer?

It forms the fundamental structure of cell membranes, allowing for compartmentalization and selective permeability.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structures, each defined by different types of bonding and interactions.

How do amino acids form polypeptides?

joined by dehydration reactions, forming peptide bonds and releasing water.

What is the primary structure of a protein?

The amino acid sequence of the polypeptide chain.

What stabilizes secondary protein structures?

Hydrogen bonds between backbone atoms stabilize α-helices and β-sheets.

What determines a protein's tertiary structure?

The overall 3D shape of a polypeptide, stabilized by various interactions including hydrogen bonds and disulfide bonds.

What is the quaternary structure of a protein?

The assembly of multiple polypeptides into a single functional protein.

What is the role of environmental factors in protein folding?

Environmental factors like pH, temperature, and water presence can affect protein folding and stability.

What are nucleic acids and their roles?

DNA and RNA, are responsible for information storage, transfer, and participation in protein synthesis.

What are the components of a nucleotide?

consists of a phosphate group, a pentose sugar, and a nitrogenous base.

What is the difference between DNA and RNA?

DNA contains deoxyribose sugar, thymine, and is usually double-stranded, while RNA contains ribose sugar, uracil, and is usually single-stranded.