Cellbiology - Glossary and Stoyanov questions

Specialized cell–cell junction, usually formed between two epithelial cells, characterized by dense plaques of protein into which intermediate filaments in the two adjoining cells are inserted.

Contents of the main compartment of the cytoplasm, excluding membrane-enclosed organelles such as
endoplasmic reticulum and mitochondria. The cell fraction remaining after membranes, cytoskeletal components,
and other organelles have been removed.

System of protein filaments in the cytoplasm of a eucaryotic cell that gives the cell shape and the capacity for directed movement. Its most abundant components are actin filaments, microtubules, and intermediate filaments.

Contents of a cell that are contained within its plasma membrane but, in the case of eucaryotic cells, outside
the nucleus.

Division of the cytoplasm of a plant or animal cell into two, as distinct from the division of its nucleus (which
is mitosis).

A structure composed of two halves. A homodimer is composed of two identical subunits, a heterodimer of two different subunits.

Double-stranded polynucleotide formed from two separate chains of covalently linked deoxyribonucleotide
units. It serves as the cell’s store of genetic information that is transmitted from generation to generation.

The enzymatic addition of methyl groups to cytosine bases in DNA. Methylation generally turns off genes by
attracting proteins that block gene expression.

The process by which a copy of a DNA molecule is made.

Uptake of material into a cell by an invagination of the plasma membrane and its internalization in a membrane-bounded vesicle.

Technique for separating mixture of proteins of DNA fragments by size and electric charge, by placing them on a polymer gel and subjecting them to an electric field. The molecules migrate through the gel at different speeds depending on their size and net charge.

Member of a family of large motor proteins that undergo ATP-dependent movement along microtubules. Dynein
is responsible for the bending of cilia.

Labyrinthine, membrane-enclosed compartment in the cytoplasm of eucaryotic cells, where lipids and secreted
and membrane-bound proteins are made.

Membrane-enclosed compartment of a eucaryotic cell through which endocytosed material passes on its way
to lysosomes.

Regulatory DNA sequence to which transcription regulators bind.

Thermodynamic quantity that measures the degree of disorder in a system; the higher the entropy, the more
the disorder.

A protein that catalyzes a specific chemical reaction.

Transmembrane receptor proteins that activate an intracellular enzyme (either a separate enzyme or part
of the receptor itself) in response to ligand binding to the extracellular part of the receptor.

Living organism composed of one or more cells with a distinct nucleus and cytoplasm. Includes all forms of
life except archaea and bacteria (the procaryotes) and viruses.

The breakdown of organic molecules without the involvement of molecular oxygen. This form of oxidation
is less complete than in aerobic processes and yields less energy.

FADH2 (reduced flavin adenine dinucleotide) A major electron carrier in metabolism produced by reduction of FAD during the oxidation of catabolites such as succinate.

Segment of a eucaryotic gene that is transcribed into RNA and expressed; dictates the amino acid sequence
of part of a protein.

Process by which most molecules are secreted (abgesondert)  from a eucaryotic cell. These molecules are packaged in membrane-enclosed vesicles that fuse with the plasma membrane, releasing their contents to the outside.

Common cell type found in connective tissue that secretes an extracellular matrix rich in collagen and
other extracellular matrix macromolecules. Migrates and proliferates readily in wounded tissue and in tissue
culture.

Extracellular matrix protein that binds to integrins on cell surfaces, helping cells to adhere to the matrix.

Communicating cell–cell junction that allows ions and small molecules to pass from the cytoplasm of one cell
to the cytoplasm of the next.

The total genetic information carried by a cell or an organism (or the DNA molecules that carry this information).

The synthesis of glucose from small organic molecules such as lactate, pyruvate, or amino acids.

Six-carbon sugar that plays a major role in the metabolism of living cells. Stored in polymeric form as glycogen
in animal cells and as starch in plant cells.

Polysaccharide composed exclusively of glucose units used to store energy in animal cells. Large granules of
glycogen are especially abundant in liver and muscle cells.

Ubiquitous metabolic pathway in the cytosol in which sugars are incompletely degraded with production of
ATP. (Literally, “sugar splitting.”)

Membrane-enclosed organelle in eucaryotic cells where the proteins and lipids made in the endoplasmic reticulum are modified and sorted for transport to other sites.

Extracellular polypeptide signaling molecule that stimulates a cell to grow or proliferate. Examples are epidermal growth factor (EGF) and platelet-derived growth factor (PDGF).

Experimental process in which two complementary nucleic acid strands form a double helix; a powerful technique for detecting specific nucleotide sequences.