Cellbiology - Glossary and Stoyanov questions

Describes a protein that can exist in two or more conformations depending on the binding of a molecule (a
ligand) at a site other than the catalytic site. Allosteric proteins composed of multiple subunits often display a cooperative response to ligand binding, because the binding of a ligand to one subunit facilitates the binding
of ligands to the other subunits.

Enzyme that attaches the correct amino acid to a tRNA molecule to form an aminoacyl-tRNA.

Having both hydrophobic and hydrophilic regions, as in a phospholipid or a detergent molecule.

Reaction pathways by which large molecules are made from smaller ones. Biosynthesis

Describes a cell, organism, or metabolic process that functions in the absence of air or, more precisely, in the absence of molecular oxygen.

Stage of mitosis during which the two sets of chromosomes separate and move away from each other. Composed of anaphase A (chromosomes move toward the two spindle poles) and anaphase B (spindle poles move apart).

A protein complex that promotes the destruction of specific proteins, by catalyzing their ubiquitylation. It is a crucial component of the cell-cycle control system.

Sequence of three nucleotides in a transfer RNA molecule that is complementary to the three-nucleotide codon on a messenger RNA molecule; each anticodon is matched to a specific amino acid covalently attached elsewhere on the transfer RNA molecule.

Describes the tip of a cell, structure, or organ. The apical surface of an epithelial cell is the exposed free surface
(opposite to the basal surface).

Normal, benign type of programmed cell death in which a cell shrinks, fragments its DNA, and alters its surface so as to activate the cell’s phagocytosis by macrophages.

Nucleoside triphosphate composed of adenine, ribose, and three phosphate groups that is the principal carrier
of chemical energy in cells. The terminal phosphate groups are highly reactive in the sense that their hydrolysis,
or transfer to another molecule, is accompanied by the release of a large amount of free energy.

Membrane-associated enzyme complex that catalyzes the formation of ATP during oxidative phosphorylation
and photosynthesis. Found in mitochondria, chloroplasts, and bacteria.

Membran-assoziierten Enzymkomplex, katalysiert die Bildung von ATP während der oxidativen Phosphorylierung
und Photosynthese. Gefunden in Mitochondrien, Chloroplasten, und Bakterien.

Long thin nerve cell process capable of rapidly conducting nerve impulses over long distances so as to deliver signals to other cells.

Situated near the base. The basal surface of a cell is opposite the apical surface.

Thin mat of extracellular matrix that separates epithelial sheets, and many types of cells such as muscle cells or fat cells, from connective tissue. Sometimes called a basement membrane.

Family of intracellular proteins that either promote or inhibit apoptosis by regulating the activation of caspases.

The symmetrical alignment of sister chromatid pairs on the mitotic spindle, such that one chromatid is attached
to one spindle pole and the other chromatid to the opposite pole.

The formation of complex molecules from simple substances by living cells.

A duplicated chromosome paired with its homologous duplicated chromosome at the beginning of meiosis.

A member of a family of proteins that mediates Ca2+-dependent cell–cell adhesion in animal tissues.

General term for the enzyme-catalyzed reactions in a cell by which complex molecules are degraded to simpler ones with release of energy. Intermediates in these catabolic reactions are sometimes called catabolites.

The acceleration of a chemical reaction due to the presence of a substance (the catalyst) that itself remains unchanged after the reaction. In cells, virtually all biochemical reactions are catalyzed (by enzymes) to enable them to occur at the temperature of living matter and within the timescale required.

Substance that accelerates a chemical reaction without itself undergoing a change. Enzymes are protein catalysts.

Protein that inhibits cyclin-Cdk complexes, primarily to inhibit progress through the G1 and S phases of the cell
cycle.

Reproductive cycle of the cell: the orderly sequence of events by which a cell duplicates its contents and divides into two.

The principle that genetic information flows from DNA to RNA to protein.

Constricted region of a mitotic chromosome that holds sister chromatids together; also the site on the DNA where the
kinetochore forms and then captures microtubules from the mitotic spindle.

Lipid molecule with a characteristic four-ringed steroid structure that is an important component of the plasma membranes of animal cells.

Complex of DNA, histones, and nonhistone proteins found in the nucleus of a eucaryotic cell. The material of which chromosomes are made.

Long threadlike structure composed of DNA and associated proteins that carries the genetic information of
an organism. Especially visible when plant and animal cells undergo mitosis or meiosis.

Process by which a chromosome becomes packed into a more compact structure prior to M phase of the cell
cycle.

Central metabolic pathway in all aerobic organisms that oxidizes acetyl groups derived from food molecules to
CO2. In eucaryotic cells these reactions are located in the mitochondrial matrix.

Fibrous protein rich in glycine and proline that is a major component of the extracellular matrix and connective
tissues. Exists in many forms: type I, the most common, is found in skin, tendon, and bone; type II is
found in cartilage; type IV is present in basal laminae; and so on.