Protein Structure and Function Quiz

<p>Thiol group (A)</p> Signup and view all the answers

<p>They join two or more segments running in opposite directions. (C)</p> Signup and view all the answers

<p>They assist in forming a compact, globular shape. (D)</p> Signup and view all the answers

<p>It removes the toxicity of hydrogen peroxide. (B)</p> Signup and view all the answers

<p>It refers to the arrangement of domains in the polypeptide chain. (B)</p> Signup and view all the answers

<p>The sequence of amino acids in a protein chain (B)</p> Signup and view all the answers

<p>NMR spectroscopy (D)</p> Signup and view all the answers

<p>Hydrogen bonds (C)</p> Signup and view all the answers

<p>Cleaving peptide bonds of proteins (B)</p> Signup and view all the answers

<p>The overall three-dimensional shape of a single polypeptide (B)</p> Signup and view all the answers

<p>Yellow (C)</p> Signup and view all the answers

<p>Millon's reaction (A)</p> Signup and view all the answers

<p>Red color (D)</p> Signup and view all the answers

<p>Rosenheim test (C)</p> Signup and view all the answers

<p>Dipeptide (C)</p> Signup and view all the answers

<p>Glucagon (A)</p> Signup and view all the answers

<p>Increases urine sodium excretion (B)</p> Signup and view all the answers

<p>Penicillin (C)</p> Signup and view all the answers

<p>It increases plasma glucose levels (D)</p> Signup and view all the answers

<p>Parathyroid hormone (PTH) (A)</p> Signup and view all the answers

<p>32 (D)</p> Signup and view all the answers

<p>Provides a scaffold for elastin deposition (D)</p> Signup and view all the answers

<p>Ultracentrifugation (C)</p> Signup and view all the answers

<p>Albumin is precipitated by half saturated (NH₄)₂SO₄ (A)</p> Signup and view all the answers

<p>A fibrous protein that assists in cell adhesion (D)</p> Signup and view all the answers

<p>Proteins from salts (B)</p> Signup and view all the answers

<p>Structural support (B)</p> Signup and view all the answers

<p>Nitrogen intake is less than nitrogen loss (B)</p> Signup and view all the answers

<p>Storing energy (B)</p> Signup and view all the answers

<p>Defence molecules (A)</p> Signup and view all the answers

<p>Uncharged polar side chain amino acids (B)</p> Signup and view all the answers

<p>Proline (C)</p> Signup and view all the answers

<p>Fibrinogen (C)</p> Signup and view all the answers

<p>20 (C)</p> Signup and view all the answers

<p>Globular proteins (B)</p> Signup and view all the answers

<p>Peptide bonds (C)</p> Signup and view all the answers

<p>Collagen (A)</p> Signup and view all the answers

<p>Hydrogen bonds and van der Waals forces (A)</p> Signup and view all the answers

<p>Preventing faulty folding of proteins (D)</p> Signup and view all the answers

<p>Boosting protein solubility with small amounts of salt (B)</p> Signup and view all the answers

<p>Hemoglobin (D)</p> Signup and view all the answers

<p>Fibrous proteins (B)</p> Signup and view all the answers

Proteins are large polymers made up of chains of amino acids. They are crucial for many functions in living organisms.

The 20 standard amino acids are the ones that are coded by DNA and are used in building mammalian proteins.

They have a carboxyl group (COOH), an amino group (NH2), a unique side chain (R), and a hydrogen atom attached to the central carbon atom.

Non-polar side chains: These amino acids are hydrophobic, meaning they don't like water.

Uncharged polar side chains: These amino acids have a neutral charge at a neutral pH.

Proteins provide structural support, act as enzymes to speed up reactions, function as hormones, transport molecules, help with clotting, act as receptors, fight off infections, and store molecules.

Nitrogen intake equals nitrogen loss, indicating a balanced state.

When nitrogen intake is less than nitrogen loss, it can occur during conditions like fasting or illness.

The removal of a carbon dioxide molecule (CO₂) from an amino acid, resulting in the formation of a biologically active amine.

A chemical reaction involving decarboxylation and deamination, producing a colored product used to detect amino acids. Most amino acids react with ninhydrin to produce a blue color, while proline reacts to form a yellow color.

A test used to detect the presence of proteins and peptides. It involves the reaction of proteins with copper sulfate (CuSO₄) in a basic environment, resulting in the formation of a complex that produces a characteristic violet color.

A chemical test specific for phenolic amino acids, such as tyrosine. It involves the reaction of tyrosine with mercury ions (Hg²⁺), leading to the formation of a red-colored complex.

A reaction that identifies aromatic amino acids like phenylalanine and tyrosine. When treated with concentrated nitric acid (HNO₃), these amino acids produce a yellow-orange colored solution.

A test specific for the indole group, found in the amino acid tryptophan. The reaction involves the interaction of tryptophan with formaldehyde and concentrated sulfuric acid, resulting in the formation of a purple ring at the interface of the two layers.

Molecules composed of two or more amino acids linked together by peptide bonds. Peptides can be classified based on their chain length.

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another amino acid.

A tripeptide found in cell membranes, composed of glutamate, cysteine, and glycine.

The thiol group (-SH) of cysteine.

Glutathione exists in two forms: the reduced form (G-SH) and the oxidized form (G-S-S-G).

A protein is a macromolecule composed of a chain of 50 or more amino acids joined by peptide bonds.

The protein's 3-dimensional structure, essential for its function.

The sequence of amino acids in a protein chain.

A bond between the carboxyl group of one amino acid and the amino group of the next.

The spatial arrangement of adjacent amino acid residues in a protein chain, stabilized by hydrogen bonds.

Globular proteins, like myoglobin and albumin, are compactly folded polypeptide chains, creating a spherical shape.

Fibrous proteins, like keratin and collagen, are extended polypeptide chains, forming a long, fiber-like structure.

Hydrogen bonds, hydrophobic interactions, disulfide bonds, and ionic interactions stabilize a protein's tertiary structure.

The quaternary structure of a protein is formed when multiple polypeptide chains (subunits) come together.

The forces that hold subunit chains together in a quaternary structure include hydrogen bonds, electrostatic bonds, hydrophobic bonds and van der Waals forces.

Chaperones are proteins that assist in the proper folding of other proteins.

Proteins with polar side chains exposed on their surface are water-soluble, like albumin.

Proteins with non-polar side chains exposed on their surface are water-insoluble, like keratin and collagen.

A method using circularly polarized light to study the secondary structure of proteins. It measures the difference in absorbance of left and right circularly polarized light, revealing information about the arrangement of amino acids in the protein.

A method using infrared light to study the secondary structure of proteins. It measures the vibrations of different chemical bonds in the protein, specifically those in the peptide backbone, which are indicative of alpha-helices and beta-sheets.

A tightly coiled, rod-like structure found in proteins, with the peptide backbone winding around a central axis. It is typically right-handed, meaning it spirals clockwise when viewed from the N-terminus.

A sheet-like structure formed by two or more polypeptide chains (or segments of the same chain) held together by hydrogen bonds between the backbone atoms. Peptide chains can run parallel or antiparallel to each other.

Segments of polypeptide chains that connect secondary structural elements. They are often rich in charged amino acids, giving them flexibility and contributing to the overall shape of the protein.

A polypeptide hormone released by the pancreas's alpha cells during fasting. It raises blood glucose levels by boosting glycogen breakdown into glucose in the liver.

A polypeptide hormone secreted by parathyroid glands when blood calcium levels are low. It raises blood calcium by increasing calcium absorption in the gut and releasing it from bones.

A polypeptide hormone secreted by thyroid gland's parafollicular cells when blood calcium levels are high. It lowers blood calcium by inhibiting bone resorption.

A fibrous protein made by fibroblasts that forms a framework for elastin deposition. It's found in structures like lens suspensory ligaments and the aorta.

A fibrous protein comprised of two identical subunits joined by disulfide bonds. It acts as a bridge between cells and the extracellular matrix.

A process that separates substances based on their distribution between a stationary phase (e.g., paper or gel) and a mobile phase (e.g., liquid).

The movement of charged particles in an electric field towards oppositely charged electrodes.

A method used to separate proteins based on their densities by spinning them at high speeds in a centrifuge.