Macromolecules: Proteins and Receptors

This is an MCQ-based quiz for GRE on the topic of Proteins and Receptors.

Receptors are generally transmembrane proteins, which bind to signaling molecules outside the cell and subsequently transmit the signal through a sequence of molecular switches to internal signaling pathways.

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An amino acid monomer at neutral pH will be found in what form?

Uncharged Negatively charged Positively charged Zwitterion

What is the name of the bond that links amino acids together in protein primary structure?

Phosphodiester bond Peptide bond Hydrogen bond Glycosidic bond

What level of protein structure is determined only by hydrogen bonds?

Tertiary structure Primary structure Quaternary structure Secondary structure

Toll-like receptors (TLRs) are known for their role in innate immunity in humans and in many other organisms. How do these receptors induce downstream signaling to induce an innate immune response?

Recognition and dimerization of integrins Recognition of coagulation factors (platelet clotting factors) Recruitment of macrophages Recognition of pathogen-associated molecular patterns (PAMPs) Recruitment of natural killer cells

Once a G-protein coupled receptor (GPCR) has bound to its ligand, which of the following steps allows the subunit to dissociate from the receptor and trigger downstream cascades?

Degradation of the GPCR's C-terminal tail that is bound to the unit None of these Exchanging the G-protein's bound ADP for an ATP Exchanging the G-protein's association with a magnesium ion for a calcium ion Exchanging the G-protein's bound GDP for a GTP

Paracrine signaling refers to which type of cell signaling?

Intracellular signaling Cell signaling across a synapse Same cell signaling Close range cell signaling Long range cell signaling

Which of the following is an example of the secondary structure of a protein?

Hydrogen bonding between R groups Hydrophobic interactions Hydrogen bonding between an amine and carbonyl group Disulfide bonds between cysteine residues Peptide bonding between amino acids

The linear sequence of amino acids in a protein determines its __________ structure.

Secondary

Quaternary

Atomic

Tertiary

Primary

Ionic bonds, disulfide bridges, hydrogen bonds and hydrophobic interactions are all examples of protein __________ structure.

Tertiary

Secondary

Primary

Quaternary

None of these

Hemoglobin is a protein that consists of four subunits: two copies of the and two copies of the subunit. How many individual polypeptide chains are present in a fully folded molecule of hemoglobin?

Two Three Four One

Quiz/Test Summary

Title: Macromolecules: Proteins and Receptors

Questions: 10

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