Biological Macromolecules and Their Functions

Definition of a Polymer: A polymer is a large molecule composed of many repeated subunits called monomers linked together by covalent bonds.
Example of a Biological Polymer: An example of a biological polymer is DNA (Deoxyribonucleic Acid), which is composed of nucleotide monomers.

Why is Glucose Not Classified as a Macromolecule?
- Glucose is a monosaccharide and is classified as a simple sugar.
- It does not have the large molecular weight characteristics of macromolecules, which include proteins, nucleic acids, and polysaccharides that consist of many repeating units.

Main Function of Enzymes: Enzymes act as catalysts in biochemical reactions, accelerating the rate of reactions by lowering the activation energy.

Dehydration Synthesis:
- This process involves the removal of a water molecule to form a bond between two molecules, resulting in the synthesis of larger molecules from smaller ones.
Hydrolysis:
- This process involves the addition of water to break down a polymer into its monomer components, essentially cleaving the bonds.

Common Monosaccharide: An example of a common monosaccharide is glucose, which is a simple sugar and a primary energy source for cells.

Why the Bond Between Two Monosaccharides is Not a Peptide Bond:
- The bond formed between two monosaccharides is a glycosidic bond, not a peptide bond. A peptide bond specifically refers to the covalent bond that links amino acids together in a protein.

Formation of a Disaccharide:
- A disaccharide is formed when two monosaccharides undergo a dehydration synthesis, resulting in a glycosidic bond.
- Example: Sucrose is a disaccharide formed from glucose and fructose.

Why Lipids Contain More C–H Bonds:
- Lipids have long hydrocarbon chains, which contribute to a higher ratio of C–H bonds compared to other biomolecules like carbohydrates or proteins.

Three Main Components of a Triglyceride:
- A glycerol backbone and three fatty acid chains are the three main components that make up a triglyceride.

Differences in Hydrogen Content:
- Saturated fatty acids contain the maximum number of hydrogen atoms, as they have no double bonds between carbon atoms.
- Unsaturated fatty acids contain one or more double bonds, which reduce the number of hydrogen atoms.

Primary Role in Cell Membranes:
- Phospholipids form the fundamental structure of cell membranes, creating a bilayer that provides barrier properties and fluidity to the cell.

Number of Different Amino Acids:
- There are 20 different amino acids used to build proteins in living organisms.
Definition of Denatured Protein:
- A denatured protein is one that has lost its three-dimensional structure due to environmental changes such as pH, temperature, or ionic concentration, thus losing its functionality.

Monomer of Nucleic Acid:
- The monomer of a nucleic acid (polynucleotide) is a nucleotide.
Three Components of a Nucleotide:
- Each nucleotide is composed of three parts: a nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and a phosphate group.

Definition of Enantiomers:
- Enantiomers are a type of stereoisomer that are non-superimposable mirror images of each other, often differing in their spatial arrangement around a chiral center.

Electrons in a Neutral Carbon Atom:
- A neutral carbon atom has 6 electrons, with 2 in the first shell and 4 in the second shell, allowing it to form four covalent bonds.
Functionality of Carbon:
- One key chemical property of carbon is its ability to form stable covalent bonds with many elements, including itself, leading to a diverse range of organic molecules.

Main Role of Functional Groups:
- Functional groups are specific groups of atoms that give organic molecules distinctive chemical properties and reactivity; they determine the properties of the molecule.

Covalent Bonds Formed by Carbon:
- A carbon atom can form four covalent bonds, allowing it to connect to other atoms in various configurations.
Branch of Chemistry for Carbon Compounds:
- Organic chemistry is the branch that studies carbon-containing compounds and their properties.
Versatility of Carbon:
- Carbon's versatility in bonding allows for a wide variety of complex molecules, facilitating the diversity of life.

Type of Bond Connecting Amino Acids:
- Peptide bonds connect amino acids in a protein, formed through dehydration synthesis.
Genetic Information Storage in Proteins:
- Proteins cannot store genetic information because their main role is as structural components and enzymes rather than information carriers.

Distinguishing Structural Feature of Unsaturated vs. Saturated Fatty Acids:
- The presence of double bonds in unsaturated fatty acids distinguishes them from saturated fatty acids, which have no double bonds.
Health Risk Linked to Saturated Fats:
- High intake of saturated fats is associated with an increased risk of cardiovascular diseases.

Involvement of Hydrogen Bonding:
- The secondary level of protein structure involves hydrogen bonding between backbone atoms, forming alpha helices and beta-pleated sheets.

Primary Energy Currency of the Cell:
- Adenosine triphosphate (ATP) serves as the primary energy currency of the cell.
Relation of DNA to RNA in Gene Expression:
- DNA provides the template for RNA synthesis during transcription, which is involved in gene expression.

Definition of Phosphodiester Bond:
- A phosphodiester bond is a covalent bond that links the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide, forming the backbone of nucleic acids.
Water's Property Allowing Dissolution of Ionic and Polar Substances:
- The polar nature of water molecules, due to their uneven distribution of charges, allows water to readily dissolve ionic and polar substances through hydrogen bonding.

Structural Polysaccharide found in Plants:
- Cellulose is a common structural polysaccharide found in plant cell walls, providing rigidity and structural support.
Digestibility of Starch vs. Cellulose in Humans:
- Humans can digest starch due to the enzyme amylase, which breaks down alpha-glucose linkages, while cellulose remains undigested since humans lack the enzymes to break down beta-glucose linkages.