Amino Acids and Peptide Bonds
This is the monomeric building block of proteins.
What is an amino acid?
The process by which the ribosome decodes mRNA to make protein is called this.
What is translation (protein synthesis)?
The linear sequence of amino acids in a polypeptide defines this level of protein structure.
What is primary structure?
This term describes a segment of a polypeptide that can fold independently into a compact, stable structure and usually has a specific function.
What is a (protein) domain?
Proteins that speed up chemical reactions in cells without being consumed are called this.
What are enzymes?
This type of covalent bond links amino acids together in a protein’s backbone.
What is a peptide bond?
This special tRNA carrying methionine is the only one that initiates translation.
What is the methionine-initiator tRNA?
Alpha-helices and beta-sheets are examples of this level of protein structure.
What is secondary structure?
Functional domains with similar sequences can be identified across proteins using information from this kind of large-scale sequence resource.
What are genome sequences (or genomic sequence data)?
Enzymes increase reaction rates by lowering this energy barrier, which otherwise keeps macromolecules stable.
What is the activation energy?
This condensation reaction process links amino acids to form a polypeptide, releasing this small molecule.
What is a condensation reaction that releases water?
Aminoacyl-tRNA synthetases attach amino acids to tRNAs using the energy from hydrolyzing this nucleotide to AMP.
What is ATP (energy comes from hydrolysis of ATP to AMP)?
This level of structure describes the overall 3D arrangement of a single polypeptide, including all side chains.
What is tertiary structure?
These covalent bonds between cysteine residues help stabilize the conformations of many secreted proteins in oxidizing environments.
What are disulfide bonds?
Cells often drive energetically unfavorable reactions forward by coupling them to this highly favorable reaction involving ATP.
What is ATP hydrolysis?
At approximately pH 7, both of these functional groups on a free amino acid are ionized.
What are the amino group and the carboxyl group?
Translation terminates when this protein, not a tRNA, binds to a stop codon in the A-site of the ribosome.
What is a release factor?
Multiple polypeptide chains assembling into a single functional protein complex define this structural level.
What is quaternary structure?
This oxygen‑binding protein is composed of two alpha-globin and two beta-globin subunits.
What is hemoglobin?
This type of regulation occurs when a metabolic pathway’s end product binds to an enzyme early in the pathway and reduces its activity.
What is feedback inhibition (usually via allostery)?
Name the four general classes of amino acid side chains shown in the lecture.
What are nonpolar (hydrophobic), uncharged polar, basic polar, and acidic polar side chains?
During initiation, the small ribosomal subunit, initiation factors, and Met-initiator tRNA bind to this modified end of the eukaryotic mRNA.
What is the 5′ cap?
Name four types of noncovalent interactions that help stabilize a folded protein’s 3D structure.
What are hydrogen bonds, electrostatic interactions, van der Waals interactions, or hydrophobic interactions?
These large RNA–protein complexes carry out translation and pre-mRNA splicing, respectively.
What are the ribosome and the spliceosome?
Small GTP-binding proteins act as molecular switches, turned on by this type of factor and turned off by this type of protein. Name both.
What are a GEF (guanine nucleotide exchange factor) to turn them on, and a GAP (GTPase-activating protein) to turn them off?