Glossary of cell biology

This glossary of cell biology is a list of definitions of terms and concepts commonly used in the study of cell biology and related disciplines in biology, including developmental biology, genetics, microbiology, molecular biology, and biochemistry.

It is intended as introductory material for novices; for more specific and technical detail, see the article corresponding to each term. For related terms, see Glossary of biology, Glossary of genetics, Glossary of developmental biology, Glossary of virology, and Glossary of chemistry.


A

acetyl-CoA
adenosine diphosphate (ADP)
adenosine monophosphate (AMP)
adenosine triphosphate (ATP)
amino acid
Any of a class of organic compounds whose basic structural formula includes a central carbon atom bonded to amine and carboxyl functional groups and to a variable side chain. Out of nearly 500 known amino acids, a set of 20 are coded for by the standard genetic code and incorporated into long polymeric chains as the building blocks of peptides and hence of polypeptides and proteins. The specific sequences of amino acids in the polypeptide chains that form a protein are ultimately responsible for determining the protein's structure and function.
anaphase
The stage of mitosis and meiosis that occurs after metaphase and before telophase, when the replicated chromosomes are segregated and each of the sister chromatids are moved to opposite sides of the cell.
apoptosis

B

binary fission

C

cadherin
chloroplast
cell
cell biology
The branch of biology that studies the structures, functions, processes, and properties of biological cells, the self-contained units of life common to all living organisms.
cell compartmentalization
The subdivision of the interior of a cell into distinct, usually membrane-bound compartments, including the nucleus and organelles (endoplasmic reticulum, mitochondria, chloroplasts, intracellular vesicles, etc.), a defining feature of the Eukarya.
cell culture
cell cycle
cell division
cell signaling
cell wall
cellular differentiation
cellular reprogramming
The conversion of a fully differentiated cell from one tissue-specific cell type to another. This involves dedifferentiation to a pluripotent state; an example is the conversion of mouse somatic cells to an undifferentiated embryonic state, which relies on the transcription factors Oct4, Sox2, Myc, and Klf4.
centriole
A cylindrical organelle composed of microtubules, present only in certain eukaryotes. A pair of centrioles migrate to and define the two opposite poles of a dividing cell where, as part of a centrosome, they initiate the growth of the spindle apparatus.
centrosome
chromosome
A nuclear DNA molecule containing part or all of the genetic material of an organism. Most eukaryotes have multiple chromosomes composed of very long linear strands of DNA coiled and condensed by histone proteins into chromatin. Chromosomes are most easily distinguished and studied in their completely condensed forms, which only occur during cell division. The circular DNA genomes of bacteria and some viruses are also sometimes called chromosomes, though they are not composed of chromatin and are not contained within a nucleus.
citric acid cycle
coenocyte
A multinucleate mass of cytoplasm bounded by a cell wall and resulting from continuous cytoplasmic growth and repeated nuclear division without cytokinesis, found in some species of algae and fungi, e.g. Vaucheria and Physarum.
coenzyme A
cyclic adenosine monophosphate (cAMP)
cytokine
cytokinesis
The final stage of cell division in both mitosis and meiosis, usually immediately following the division of the nucleus, during which the cytoplasm of the parent cell is cleaved and divided approximately evenly between the two daughter cells. In animal cells, this process occurs by the closing of a microfilament contractile ring in the equatorial region of the dividing cell. Contrast karyokinesis.
cytology
The study of the morphology, processes, and life history of living cells, particularly by means of light and electron microscopy. The term is also sometimes used as a synonym for the broader field of cell biology.
cytolysis
See lysis.
cytoplasm
cytosol

Also hyaloplasm.

The soluble phase of the cytoplasm, in which small particles such as ribosomes, proteins, nucleic acids, and many other molecules are suspended or dissolved, excluding larger structures and organelles such as mitochondria, chloroplasts, lysosomes, and the endoplasmic reticulum.

D

deoxyribonucleic acid (DNA)
A polymeric nucleic acid molecule composed of a linear chain of deoxyribonucleotides, each of which incorporates one of four canonical nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T). DNA is most often found in double-stranded form, where two chains or strands are paired together by hydrogen bonds between the individual nucleotides of each strand. This structure commonly occurs in the shape of a double helix. By storing and encoding genetic information in the sequence of its nucleotides, DNA serves as the universal molecular basis of biological inheritance and the fundamental template from which all proteins, cells, and living organisms are constructed.
desmosome
desynapsis
The failure of homologous chromosomes that have synapsed normally during pachynema to remain paired during diplonema. Desynapsis is usually caused by the improper formation of chiasmata. Contrast asynapsis.
developmental biology
diakinesis
In meiosis, the fifth and final substage of prophase I, following diplonema and preceding metaphase I. During diakinesis, the chromosomes are further condensed, the two centrosomes reach opposite poles of the cell, and the spindle apparatus begins to extend from the poles to the equator.
diplonema

Also diplotene stage.

In meiosis, the fourth of the five substages of prophase I, following pachynema and preceding diakinesis. During diplonema, the synaptonemal complex disassembles and the paired homologous chromosomes begin to separate from one another, though they remain tightly bound at the chiasmata where chromosomal crossover has occurred.
DNA
See deoxyribonucleic acid.

E

electron transport chain
embryo
endocytosis
endomembrane
Any membrane surrounding an intracellular organelle or vesicle, e.g. that of the endoplasmic reticulum, Golgi apparatus, lysosome, vacuole, nucleus (the nuclear envelope), etc.
endoplasmic reticulum (ER)
endosome
enucleate
To artificially remove the nucleus from a cell, e.g. by micromanipulation in the laboratory or by destroying it through irradiation with ultraviolet light, rendering the cell anucleate.
envagination
exocytosis
exosome
1.  (protein complex) An intracellular multi-protein complex which serves the function of degrading various types of RNA molecules.
2.  (vesicle) A type of membrane-bound extracellular vesicle produced in many eukaryotic cells by the inward budding of an endosome and the subsequent fusion of the endosome with the plasma membrane, causing the release of the vesicle into various extracellular spaces, including biological fluids such as blood and saliva, where they may serve any of a wide variety of physiological functions, from waste management to intercellular signaling.
extracellular
Outside the plasma membrane of a cell or cells; i.e. located or occurring externally to a cell. Contrast intracellular; see also intercellular.
extracellular matrix (ECM)

F

fermentation

G

G1
G2
gamete
A haploid cell that is the meiotic product of a progenitor germ cell and the final product of the germ line in sexually reproducing multicellular organisms. Gametes are the means by which an organism passes its genetic information to its offspring; during fertilization, two gametes (one from each parent) are fused into a single diploid zygote.
germ cell
Any cell that gives rise to the gametes of a sexually reproducing organism. Germ cells are the vessels for the genetic material which will ultimately be passed on to the organism's descendants and are usually distinguished from somatic cells, which are entirely separate from the germ line.
Golgi apparatus

H

Hayflick limit
histology
The study or analysis of the microscopic anatomy of biological tissues or of cells within tissues, particularly by making use of specialized techniques to distinguish structures and functions based on visual morphology and differential staining. In practice the term is sometimes used more broadly to include cytology.
hyaloplasm
See cytosol.

I

intercellular
Between two or more cells. Contrast intracellular; see also extracellular.
interkinesis

Also interphase II.

The abbreviated pause in activities related to cell division that occurs during meiosis in some species, between the first and second meiotic divisions (i.e. meiosis I and meiosis II). DNA replication does not occur during interkinesis, unlike during the normal interphase that precedes meiosis I and mitosis.
interphase
All stages of the cell cycle excluding cell division. A typical cell spends most of its life in interphase, during which it conducts everyday metabolic activities as well as the complete replication of its genome in preparation for mitosis or meiosis.
intracellular
Within a cell or cells; i.e. inside the plasma membrane. Contrast intercellular and extracellular.
invagination
The infolding of a membrane toward the interior of a cell or organelle, or of a sheet of cells toward the interior of a developing embryo, tissue, or organ, forming a distinct membrane-lined pocket. In the case of individual cells, the invaginated pocket may proceed to separate from the source membrane entirely, creating a membrane-bound vesicle within the cell, as in endocytosis.
ionophore
Any chemical compound or macromolecule that facilitates the movement of ions across biological membranes, or more specifically, any chemical species that reversibly binds electrically charged atoms or molecules. Many ionophores are lipid-soluble proteins that catalyze the transport of monovalent and divalent cations across the hydrophobic lipid bilayers surrounding cells and vesicles.

J

K

karyon
See nucleus.
kinetochore
A disc-shaped protein complex which assembles around the centromere of a chromosome during prometaphase of mitosis and meiosis, where it functions as the attachment point for microtubules of the spindle apparatus.
Krebs cycle
See citric acid cycle.

L

leptonema

Also leptotene stage.

In meiosis, the first of five substages of prophase I, following interphase and preceding zygonema. During leptonema, the replicated chromosomes condense from diffuse chromatin into long, thin strands that are much more visible within the nucleus.
lysis
The disruption and decomposition of the plasma membrane surrounding a cell, or more generally of any membrane-bound organelle or vesicle, especially by osmotic, enzymatic, or other chemical or mechanical processes which compromise the membrane's integrity and thereby cause the unobstructed interchange of the contents of intracellular and extracellular spaces. Lysis generally implies the complete and irreversible loss of intracellular organization as a result of the release of the cell's internal components and the dilution of the cytosol, and therefore the death of the cell. Such a cell is said to be lysed, and a fluid containing the contents of lysed cells (often including nucleic acids, proteins, and many other organic molecules) is called a lysate. Lysis may occur both naturally and artificially, and is a normal part of the cellular life cycle.
lysosome

M

M phase
See mitosis.
meiosis
metaphase
microtubule
mitochondrion
mitosis
mitotic spindle
See spindle apparatus.
motor protein

N

nuclear membrane
nucleolus
nucleus

O

occluding junction
organelle
oxidative phosphorylation

P

pachynema
phagocyte
phagocytosis
phagosome
phospholipid bilayer
plasma membrane
plastid
pluripotency
prometaphase
prophase
proton motive force

Q

R

ribosome

S

S phase
somatic cell
spindle apparatus
stem cell
syncytium

T

telophase
totipotency
transmembrane protein
tricarboxylic acid cycle (TCA)
See citric acid cycle.

U

V

vacuole
vesicle

W

X

Y

Z

See also



This page was last updated at 2023-03-27 07:14 UTC. Update now. View original page.

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