Life Sciences Glossary

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-10 sequence

The -10 sequence is the consensus sequence centered about 10 bp before the startpoint of a bacterial gene. It is involved in melting DNA during the initiation reaction.

Defined as key term in
Molecular Biology—Essentials  3.11.8 Promoter recognition depends on consensus sequences
Molecular Biology  3.9.12 Promoter recognition depends on consensus sequences

-35 sequence

The -35 sequence is the consensus sequence centered about 35 bp before the startpoint of a bacterial gene. It is involved in initial recognition by RNA polymerase.

Defined as key term in
Molecular Biology—Essentials  3.11.8 Promoter recognition depends on consensus sequences
Molecular Biology  3.9.12 Promoter recognition depends on consensus sequences

α-catenin

α-catenin is an adapter protein that binds to β-catenin and actin filaments in cadherin receptor complexes.

Defined as key term in
Cell Biology  6.14.22 Calcium-dependent cadherins mediate adhesion between cells
Cell Biology  6.14.22 Calcium-dependent cadherins mediate adhesion between cells

γ-tubulin

γ-tubulin is member of the tubulin protein superfamily. It is found at the centrosome, where it functions to nucleate microtubules as part of a complex with several other proteins. Many cells also contain γ-tubulin in other locations.

Defined as key term in
Cell Biology  4.7.7 Cells use microtubule organizing centers to nucleate microtubule assembly

γ-tubulin ring complex

The γ-tubulin ring complex (γTuRC) is a complex of about 10 proteins that includes γ-tubulin. It nucleates microtubules and is a component of centrosomes.

Defined as key term in
Cell Biology  4.7.7 Cells use microtubule organizing centers to nucleate microtubule assembly

att

att sites are the loci on a lambda phage and the bacterial chromosome at which recombination integrates the phage into, or excises it from, the bacterial chromosome.

Defined as key term in
Molecular Biology—Essentials  4.19.12 Specialized recombination in phage lambda involves specific sites
Molecular Biology  4.15.16 Specialized recombination involves specific sites

cis

cis configuration describes two sites on the same molecule of DNA.

Defined as key term in
Molecular Biology  1.1.25 Proteins are trans-acting but sites on DNA are cis-acting

cis face

The cis face of the Golgi is the side juxtaposed to the nucleus.

Defined as key term in
Molecular Biology  7.32.6 ER and Golgi

cis-acting

A cis-acting site affects the activity only of sequences on its own molecule of DNA (or RNA); this property usually implies that the site does not code for protein.

Defined as key term in
Molecular Biology—Essentials  1.2.12 Proteins are trans-acting but sites on DNA are cis-acting
Molecular Biology—Essentials  3.12.1 Introduction
Molecular Biology  1.1.25 Proteins are trans-acting but sites on DNA are cis-acting
Molecular Biology  3.10.1 Introduction

cis-dominant

A cis-dominant site or mutation affects the properties only of its own molecule of DNA. cis-dominance is taken to indicate that a site does not code for a diffusible product. (A rare exception is that a protein is cis-dominant when it is constrained to act only on the DNA or RNA from which it was synthesized.)

Defined as key term in
Genetics  2.6.21 Genetic changes can lead to loss of function or gain of function
Molecular Biology  3.10.7 cis-acting constitutive mutations identify the operator

cis-Golgi network

The cis, or entry, face of the Golgi apparatus is a reticulum of interconnected tubules called the cis-Golgi network.

Defined as key term in
Cell Biology  2.4.2 Overview of the exocytic pathway

In situ hybridization

In situ hybridization is performed by denaturing the DNA of cells squashed on a microscope slide so that reaction is possible with an added single-stranded RNA or DNA; the added preparation is radioactively labeled and its hybridization is followed by autoradiography.

Defined as key term in
Cell Biology  3.6.13 Polytene chromosomes form bands
Genetics  2.11.16 Physical mapping makes use of long-range restriction maps, large insert DNA clone maps, and the genome sequence
Molecular Biology—Essentials  1.6.9 Satellite DNAs often lie in heterochromatin
Molecular Biology—Essentials  6.28.8 Polytene chromosomes form bands that puff at sites of gene expression
Molecular Biology  1.4.11 Satellite DNAs often lie in heterochromatin
Molecular Biology  5.19.10 Polytene chromosomes form bands

In vitro complementation

In vitro complementation is a functional assay used to identify components of a process. The reaction is reconstructed using extracts from a mutant cell. Fractions from wild-type cells are then tested for restoration of activity.

Defined as key term in
Molecular Biology  4.14.1 Introduction

rec

rec mutations of E. coli cannot undertake general recombination.

Defined as key term in
Molecular Biology—Essentials  4.19.6 RecBCD generates free ends for recombination
Molecular Biology  4.15.8 The bacterial RecBCD system is stimulated by chi sequences

rut

rut is an acronym for rho utilization site, the sequence of RNA that is recognized by the rho termination factor.

Defined as key term in
Molecular Biology  3.9.22 How does rho factor work?

trans

trans configuration of two sites refers to their presence on two different molecules of DNA (chromosomes).

Defined as key term in
Molecular Biology—Essentials  1.2.12 Proteins are trans-acting but sites on DNA are cis-acting
Molecular Biology  1.1.25 Proteins are trans-acting but sites on DNA are cis-acting

trans face

The trans face of the Golgi is juxtaposed to the plasma membrane.

Defined as key term in
Molecular Biology  7.32.6 ER and Golgi

trans-acting

A trans-acting product can function on any copy of its target DNA. This implies that it is a diffusible protein or RNA.

Defined as key term in
Molecular Biology—Essentials  3.12.1 Introduction
Molecular Biology  3.10.1 Introduction

trans-dominant

trans-dominant mutant proteins are produced by dominant negative mutations.

Defined as key term in
Genetics  2.6.21 Genetic changes can lead to loss of function or gain of function

trans-Golgi network [advanced definition]

The trans, or exit, face of the Golgi apparatus is a reticulum of interconnected tubules called the trans-Golgi network. It serves as a sorting station where molecules destined for different locations are incorporated in different vesicles.

Defined as key term in
Introduction to Biology  3.12.6 The secretory pathway delivers new proteins and lipids to the cell surface
Cell Biology  2.4.17 Sorting of lysosomal proteins occurs in the trans-Golgi network
Cell Biology  2.4.2 Overview of the exocytic pathway

trans-Golgi network [simple definition]

The trans-Golgi network is the last part of the Golgi apparatus. It serves as a sorting station where molecules destined for different locations become packaged in different vesicles.

Defined as key term in
Introduction to Biology  3.12.6 The secretory pathway delivers new proteins and lipids to the cell surface
Cell Biology  2.4.17 Sorting of lysosomal proteins occurs in the trans-Golgi network
Cell Biology  2.4.2 Overview of the exocytic pathway

10 nm fiber

The 10 nm fiber is a linear array of nucleosomes, generated by unfolding from the natural condition of chromatin.

Defined as key term in
Cell Biology  3.6.20 The path of nucleosomes in the chromatin fiber
Molecular Biology—Essentials  6.29.8 The path of nucleosomes in the chromatin fiber
Molecular Biology  5.20.7 The path of nucleosomes in the chromatin fiber

19S regulatory complex

The 19S regulatory complex binds to one or both ends of the 20S proteasome and controls the entry of polypeptides into it.

Defined as key term in
Biochemistry  1.4.2 Overview of the ubiquitin-proteasome system

20S proteasome

The 20S proteasome is a cylindrical protein complex that forms the core of the 26S proteasome and contains its protease sites.

Defined as key term in
Biochemistry  1.4.2 Overview of the ubiquitin-proteasome system

26S proteasome

The 26S proteasome is a large complex of proteins that degrades polyubiquitinated proteins. It is composed of one copy of the 20S proteasome and either one or two copies of the 19S regulatory complex.

Defined as key term in
Biochemistry  1.4.2 Overview of the ubiquitin-proteasome system

30 nm fiber

The 30 nm fiber is a coiled coil of nucleosomes. It is the basic level of organization of nucleosomes in chromatin.

Defined as key term in
Cell Biology  3.6.20 The path of nucleosomes in the chromatin fiber
Molecular Biology—Essentials  6.29.8 The path of nucleosomes in the chromatin fiber
Molecular Biology  5.20.7 The path of nucleosomes in the chromatin fiber

45S RNA

45S RNA is a precursor that contains the sequences of both major ribosomal RNAs (28S and 18S rRNAs).

Defined as key term in
Molecular Biology  5.24.21 Production of rRNA requires cleavage events

5.8S RNA

5.8S RNA is an independent small RNA present on the large subunit of eukaryotic ribosomes. It is homologous to the 5′ end of bacterial 23S rRNA.

Defined as key term in
Molecular Biology  2.6.16 Ribosomal RNA pervades both ribosomal subunits

5S RNA

5S RNA is a 120 base RNA that is a component of the large subunit of the ribosome.

Defined as key term in
Molecular Biology  2.6.16 Ribosomal RNA pervades both ribosomal subunits

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