Large Molecules of Life Quiz

Study Notes

Living things are composed of four main classes of macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
Macromolecules (huge molecules) are constructed from thousands of atoms.
Molecular structure and function are inseparably intertwined.

Polymers are long chains of repeating smaller building blocks called monomers.
Three of the four classes of life’s organic molecules are polymers: carbohydrates, proteins, and nucleic acids.

Two monomers bond together through the loss of a water molecule in a dehydration reaction.
Polymers are broken down into monomers by hydrolysis, which adds a water molecule and essentially reverses dehydration reaction.

Each cell contains thousands of different macromolecules.
Macromolecules vary between cells within an organism, and even more so between species.
A wide variety of polymers can be generated from a small set of monomers.

Carbohydrates include sugars and their polymers.
Simple carbohydrates are monosaccharides, or single sugars.
Polysaccharides are carbohydrate macromolecules composed of many sugar building blocks.

Monosaccharide molecules have molecular formulas that are multiples of CH2O.
Glucose (C6H12O6) is the most prevalent monosaccharide.
Monosaccharides are classified by:
- The location of the carbonyl group (aldehyde or ketone).
- The number of carbons in their carbon skeleton.

Proteins are a diverse group of macromolecules found in cells
Proteins comprise more than 50% of the dry weight of most cells
Proteins play various roles in cells and organisms, including structural support, storage, transport, cellular communication, movement, and defense against foreign substances
Enzymes are a type of protein that act as catalysts to speed up chemical reactions
Enzymes perform their functions repeatedly, functioning as workhorses in life processes
Proteins are polymers built from amino acid monomers.
There are 20 different types of amino acids
Each amino acid has a unique side chain, called an R group, that determines its chemical properties.
Amino acids are linked together by peptide bonds to form polypeptides
Polypeptides can range in length from a few to thousands of amino acids
The sequence of amino acids in a polypeptide is its unique linear sequence
A functional protein consists of one or more polypeptides folded and coiled into a specific three-dimensional shape
The shape of a protein is determined by its amino acid sequence and interactions between amino acids
The specific shape of a protein allows it to perform its function

The intricate structure of a protein can be described at four levels:
- Primary structure: The linear sequence of amino acids in a polypeptide chain.
- Secondary structure: The local folding of the polypeptide chain, which can include alpha-helices and beta-sheets.
- Tertiary structure: The three-dimensional shape of a single polypeptide chain.
- Quaternary structure: The arrangement of multiple polypeptide chains in a protein complex.
The primary structure of a protein is determined by its genetic code, and the secondary, tertiary, and quaternary structures are determined by interactions between amino acids, such as hydrogen bonding, ionic interactions, hydrophobic interactions, and disulfide bridges.
Specific amino acid sequences dictate the specific structure of a protein.
The structure of a protein determines its function.

The unique three-dimensional shape of each protein enables it to recognize and bind to specific molecules.
These interactions are crucial for protein function.
Some protein functions include:
Enzymes: Catalyze biochemical reactions by speeding up the rate of reactions.
Structural proteins: Provide support and shape to cells and tissues.
Storage proteins: Store amino acids for later use.
Transport proteins: Move molecules across cell membranes.
Hormones: Act as chemical messengers to regulate cellular processes.
Antibodies: Defend the body against disease by binding to and destroying pathogens.
The function of a protein can be disrupted by changes in its structure, such as mutations in its amino acid sequence or exposure to high temperatures or harsh chemicals. This disruption can lead to disease and disorders.