Protein Structure and Function Quiz

Organic molecules that are the building blocks of proteins and peptides.

Amino acids that our bodies cannot synthesize and must be obtained from our diet.

Short chains of amino acids linked together by peptide bonds.

Large, complex molecules composed of long chains of amino acids linked together by peptide bonds.

They form when an amino acid loses a proton from its carboxyl group and gains a proton on its amino group.

The arrangement of atoms in a molecule that determines its chirality (handedness).

The most common form of amino acids found in proteins.

Six amino acids with hydrophobic side chains that repel water.

Selenocysteine is the 21st amino acid found in some organisms. It has its own unique RNA codon, making it distinct from the standard 20 amino acids.

Essential amino acids are those that the human body cannot synthesize in sufficient amounts and must be obtained from the diet.

Protein is a source of amino acids. Consuming protein provides the body with essential amino acids it needs.

A peptide bond is a special type of covalent bond that links two amino acids together. It forms between the carboxyl group of one amino acid and the amino group of another.

A peptide bond replaces the charged groups of amino acids, making the protein chain neutral. This allows for hydrogen bonding, which contributes to the stability of proteins.

Peptide bonds are very resistant to degradation, ensuring the stability of proteins. This is crucial for proteins that have important structural roles, such as keratin in hair, nails, and claws.

Protein synthesis is the process of creating proteins from amino acids. This occurs at ribosomes, which are cellular structures.

Proteases are enzymes that break down proteins. They do this by breaking peptide bonds, the bonds that hold amino acids together.

The process of breaking down a molecule by adding water.

A type of organic chemistry reaction where a molecule containing a carbonyl group (C=O) is broken down.

A type of nucleic acid that is responsible for carrying genetic information from DNA to ribosomes where proteins are synthesized.

Genetic code that specifies which amino acid should be added to a protein chain.

A sequence of three RNA bases that specifies a specific amino acid.

The process of copying the genetic information from DNA into RNA.

The process of converting the genetic information in RNA into a protein.

A type of RNA molecule that carries an amino acid to the ribosome during protein synthesis.

A type of secondary protein structure stabilized by hydrogen bonding between amino acids along the protein chain, forming a helical shape.

A specific region within a protein with a distinct three-dimensional structure, often having its own function.

The overall three-dimensional shape of a protein molecule, determined by interactions between the amino acid side chains, including hydrogen bonding, ionic interactions, and hydrophobic interactions.

A protein that provides structural support and is found in various tissues like hair, skin, and nails.

The combination of multiple polypeptide chains to form a functional protein complex.

A covalent bond formed between two sulfur atoms in cysteine amino acid residues within a protein. It helps stabilize protein structure and can link separate polypeptide chains.

The process of forming a disulfide bond by oxidizing two thiol groups.

The process of breaking a disulfide bond by adding electrons to the sulfur atoms.

The amino acid cysteine (Cys) contains a thiol group that can form disulfide bonds.

Proteins with more disulfide bonds are typically more rigid and stable. This is important for structures like hair and nails.

The protein keratin has varying amounts of disulfide bonds, leading to different structural properties. Keratin in hair has fewer disulfide bonds than keratin in nails, resulting in a more flexible structure.

Proteins that contain multiple polypeptide chains held together by disulfide bonds.

Disulfide bonds are significant in proteins because they contribute to their structure and stability, allowing for diverse functional roles.

Hydrophobic side chains tend to be found in the interior of proteins due to their aversion to water. They are also crucial for allowing proteins to cross cell membranes, creating passages between compartments.

Glycine (Gly) and Proline (Pro) have unique structures that make them adaptable, aiding flexibility in protein loops and rigidity in structural elements.

In a typical cellular environment, acidic groups lose a proton (H+) becoming negatively charged. Basic groups gain a proton (H+) and become positively charged.

The charged ends of acidic (-ve) and basic (+ve) sidechains attract each other, forming stable electrostatic interactions. These "salt bridges" are crucial for protein interactions.

Electrostatic interactions, where positive and negative charges are attracted, help proteins bind to each other. This is vital in protein recognition and communication.

Proteins can be visualised with electrostatic interactions represented by colours: blue for positive charges and red for negative charges.

Amino acid sidechains can be either hydrophobic or hydrophilic, influencing their position within a protein and their role in interactions.

The specific arrangement and interactions of amino acids determine the overall structure and function of a protein. These interactions can be either hydrophobic, electrostatic, or hydrogen bonding.